Soluble fibroblast growth factor receptor 3 (SFGFR3) polypeptides and uses thereof
11697678 · 2023-07-11
Assignee
- Pfizer Inc. (New York, NY)
- INSERM (Institut National de la Santé et de la Recherche Médicale) (Paris, FR)
- Université Côte d'Azur (Nice, FR)
Inventors
Cpc classification
International classification
Abstract
The invention features soluble fibroblast growth factor receptor 3 (sFGFR3) polypeptides. The invention also features methods of using sFGFR3 polypeptides to treat skeletal growth regardation disorders, such as achondroplasia.
Claims
1. A polynucleotide encoding a soluble fibroblast growth factor receptor 3 (sFGFR3) polypeptide comprising the amino acid sequence of SEQ ID NO: 33.
2. The polynucleotide of claim 1, wherein the polynucleotide comprises a nucleic acid sequence at least 80% identical to nucleotides 58-1104 of SEQ ID NO: 37.
3. The polynucleotide of claim 1, wherein the polynucleotide comprises the nucleic acid sequence of nucleotides 58-1104 of SEQ ID NO: 37.
4. The polynucleotide of claim 1, wherein the polynucleotide comprises a nucleic acid sequence at least 80% identical to nucleotides 52-1098 of SEQ ID NO: 21.
5. The polynucleotide of claim 1, wherein the polynucleotide comprises the nucleic acid sequence of nucleotides 52-1098 of SEQ ID NO: 21.
6. The polynucleotide of claim 1, wherein the sFGFR3 polypeptide binds to fibroblast growth factor 1 (FGF1), fibroblast growth factor 2 (FGF2), fibroblast growth factor 9 (FGF9), fibroblast growth factor 18 (FGF18), fibroblast growth factor 19 (FGF19), or fibroblast growth factor 21 (FGF21).
7. The polynucleotide of claim 6, wherein the binding is characterized by a K.sub.d of about 1 nM to about 10 nM.
8. A vector comprising the polynucleotide of claim 1.
9. The vector of claim 8, wherein the vector comprises the nucleic acid sequence of nucleotides 58-1104 of SEQ ID NO: 37.
10. The vector of claim 8, wherein the vector comprises the nucleic acid sequence of SEQ ID NO: 37.
11. The vector of claim 8, wherein the vector comprises the nucleic acid sequence of nucleotides 52-1098 of SEQ ID NO: 21.
12. The vector of claim 8, wherein the vector is a plasmid, an artificial chromosome, a viral vector or a phage vector.
13. A method of producing a soluble fibroblast growth factor receptor 3 (sFGFR3) polypeptide, the method comprising: (i) culturing a host cell comprising the polynucleotide of claim 1 in a culture medium under conditions suitable for expression of the sFGFR3 polypeptide; and (ii) recovering the sFGFR3 polypeptide from the culture medium.
14. The method of claim 13, wherein the polynucleotide comprises the nucleic acid sequence of nucleotides 58-1104 of SEQ ID NO: 37, or the nucleic acid sequence of nucleotides 52-1098 of SEQ ID NO: 21.
15. The method of claim 13, wherein the host cell is a HEK293 cell or CHO cell.
16. A method of producing a soluble fibroblast growth factor receptor 3 (sFGFR3) polypeptide, the method comprising: (i) culturing a host cell comprising the vector of claim 8 in a culture medium under conditions suitable for expression of the sFGFR3 polypeptide; and (ii) recovering the sFGFR3 polypeptide from the culture medium.
17. The method of claim 16, wherein the vector comprises the nucleic acid sequence of nucleotides 58-1104 of SEQ NO: 37, or the nucleic acid sequence of nucleotides 52-1098 of SEQ ID NO: 21.
18. The method of claim 16, wherein the vector comprises the nucleic acid sequence of SEQ ID NO: 37.
19. The method of claim 16, wherein the host cell is a HEK293 cell or CHO cell.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
(22) We have discovered that soluble fibroblast growth factor receptor 3 (sFGFR3) polypeptides and variants thereof can be used to treat skeletal growth retardation disorders, such as achondroplasia, in a patient (e.g., a human, particularly an infant, a child, or an adolescent). In particular, sFGFR3 polypeptides of the invention feature a deletion of, e.g., amino acids 289 to 400 of SEQ ID NO: 5 or amino acids 311 to 422 of SEQ ID NO: 32, to provide the following exemplary sFGFR3 polypeptides: sFGFR3_Del4 including an amino acid substitution of a cysteine residue with a serine residue at position 253 (sFGFR3_Del4-C253S; SEQ ID NO: 2) and sFGFR3_Del4 including an extended Ig-like C2-type domain 3 (sFGFR3_Del4-D3; SEQ ID NO: 33) and variants thereof, such as a sFGFR3 polypeptide having the amino acid sequence of SEQ ID NO: 4. Additionally, the sFGFR3 polypeptides may include a signal peptide, such as a sFGFR3 polypeptide having the amino acid sequence of SEQ ID NO: 18 or 34. See U.S. Provisional Application No. 62/276,222 and International Application No. PCT/US16/12553 for a description of sFGFR3_Del4 (SEQ ID NO: 1), each of which is hereby incorporated herein by reference in their entirety.
(23) For example, sFGFR3 polypeptides and variants thereof having at least 85% sequence identity (e.g., at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) to the amino acid sequence of SEQ ID NO: 1 can include an amino acid substitution that removes a cysteine residue at position 253 of SEQ ID NO: 1 (e.g. sFGFR3_Del4-C253S; a polypeptide having the amino acid sequence of SEQ ID NO: 2). In particular, an sFGFR3 polypeptide of the invention can include a substitution of a cysteine residue at position 253 of SEQ ID NO: 1 with, e.g., a serine residue. For example, the cysteine residue at position 253 is substituted with a serine residue or, e.g., another conservative amino acid substitution, such as alanine, glycine, proline, or threonine.
(24) The sFGFR3 polypeptides can also include a polypeptide sequence having at least 90% (e.g., at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) amino acid sequence identity to amino acid residues 23 to 357 of SEQ ID NO: 32, in which the polypeptide lacks a signal peptide and a transmembrane domain of FGFR3 and (i) is less than 500 amino acids in length; (ii) comprises 200 consecutive amino acids or fewer of an intracellular domain of FGFR3; and/or (iii) lacks a tyrosine kinase domain of FGFR3 (e.g., sFGFR3_Del4-D3; a polypeptide having the amino acid sequence of SEQ ID NO: 33). Methods for administering the sFGFR3 polypeptides of the invention to treat skeletal growth retardation disorders (e.g., achondroplasia) in a patient (e.g., a human, particularly an infant, a child, or an adolescent) are also described.
(25) The sFGFR3 polypeptides, methods of production, methods of treatment, compositions, and kits of the invention are described herein.
(26) Soluble Fibroblast Growth Factor Receptor 3 (sFGFR3) Polypeptides
(27) The invention features sFGFR3 polypeptides and variants thereof formulated for the treatment of skeletal growth retardation disorders (e.g., achondroplasia). In particular, the sFGFR3 polypeptides can have at least 85% sequence identity (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) to the amino acid sequence of SEQ ID NO: 1, in which the sFGFR3 polypeptide includes an amino acid substitution that removes a cysteine residue at position 253 of SEQ ID NO: 1 (e.g. sFGFR3_Del4-C253S; a polypeptide having the amino acid sequence of SEQ ID NO: 2). For example, the cysteine residue at position 253 of SEQ ID NO: 1 is substituted with a serine residue or a conservative amino acid substitution, such as alanine, glycine, proline, or threonine.
(28) The sFGFR3 polypeptides and variants thereof can also include fragments of the amino acid sequence of SEQ ID NO: 2 (e.g., at least amino acids 1 to 200, 1 to 205, 1 to 210, 1 to 215, 1 to 220, 1 to 225, 1 to 235, 1 to 230, 1 to 240, 1 to 245, 1 to 250, 1 to 253, 1 to 255, 1 to 260, 1 to 265, 1 to 275, 1 to 280, 1 to 285, 1 to 290, or 1 to 300, of SEQ ID NO: 2) having at least 50% sequence identity (e.g., 55%, 60%, 65%, 70%, 75%, 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) to SEQ ID NO: 2. Additionally, sFGFR3 polypeptides can include amino acids 1 to 301 of SEQ ID NO: 1, in which the sFGFR3 polypeptide includes an amino acid substitution of a cysteine residue with a serine residue at position 253 of SEQ ID NO: 1 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 2).
(29) The sFGFR3 polypeptides and variants thereof can also include fragments of the amino acid sequence of SEQ ID NO: 33 (e.g., at least amino acids 1 to 200, 1 to 210, 1 to 220, 1 to 230, 1 to 240, 1 to 250, 1 to 260, 1 to 270, 1 to 280, 1 to 290, 1 to 300, 1 to 310, 1 to 320, 1 to 330, 1 to 340, 1 to 340, or 1 to 345 of SEQ ID NO: 33) having at least 50% sequence identity (e.g., 55%, 60%, 65%, 70%, 75%, 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) to SEQ ID NO: 33. In addition, the cysteine residue at position 253 of SEQ ID NO: 4 or 33 and/or position 316 of SEQ ID NO: 4, if present, can be substituted with a serine residue or a conservative amino acid substitution, such as alanine, glycine, proline, or threonine.
(30) Given the results described herein, the invention is not limited to a particular sFGFR3 polypeptide or variants thereof. In addition to the exemplary sFGFR3 polypeptides and variants thereof discussed above, any polypeptide that binds one or more FGFs (e.g., FGF1 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 13), FGF2 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 14), FGF9 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 15), FGF18 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 16), FGF19 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 38), and/or FGF21 (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 39)) with similar binding affinity as the sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be used in the methods, such as for treating a skeletal growth retardation disorder, e.g., achondroplasia. The sFGFR3 polypeptides can be, for example, fragments of FGFR3 isoform 2 lacking exons 8 and 9 encoding the C-terminal half of the Ig-like C2-type domain 3 and exon 10 including the transmembrane domain (e.g., fragments of the amino acid sequence of SEQ ID NO: 5 or 32), corresponding to fragments of FGFR3 transcript variant 2 (Accession No. NM_022965).
(31) An sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4)) can include a signal peptide at the N-terminal position. An exemplary signal peptide can include, but is not limited to, amino acids 1 to 22 of SEQ ID NO: 6 (e.g., MGAPACALALCVAVAIVAGASS) or amino acids 1 to 19 of SEQ ID NO: 35 (e.g., MMSFVSLLLVGILFHATQA). Accordingly, the sFGFR3 polypeptides include both secreted forms, which lack the N-terminal signal peptide, and non-secreted forms, which include the N-terminal signal peptide. For instance, a secreted sFGFR3 polypeptide can include the amino acid sequence of SEQ ID NOs: 2, 4, or 33. Alternatively, the sFGFR3 polypeptide does include a signal peptide, such the amino acid sequence of SEQ ID NOs: 18, 19, or 34. One skilled in the art will appreciate that the position of the N-terminal signal peptide will vary in different sFGFR3 polypeptides and can include, for example, the first 5, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 30, or more amino acid residues on the N-terminus of the polypeptide. One of skill in the art can predict the position of a signal sequence cleavage site, e.g., by an appropriate computer algorithm such as that described in Bendtsen et al. (J. Mol. Biol. 340(4):783-795, 2004) and available on the Web at cbs.dtu.dk/services/SignalP/.
(32) Additionally, sFGFR3 polypeptides (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) of the invention can be glycosylated. In particular, a sFGFR3 polypeptide can be altered to increase or decrease the extent to which the sFGFR3 polypeptide is glycosylated. Addition or deletion of glycosylation sites to an sFGFR3 polypeptide can be accomplished by altering the amino acid sequence such that one or more glycosylation sites is created or removed. For example, N-linked glycosylation, in which an oligosaccharide is attached to the amide nitrogen of an asparagine residue, can occur at position Asn76, Asn148, Asn169, Asn 203, Asn240, Asn272, and/or Asn 294 of the amino acid sequence of sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 4 or 33), and variants thereof. One or more of these Asn residues can also be substituted to remove the glycosylation site. For instance, O-linked glycosylation, in which an oligosaccharide is attached to an oxygen atom of an amino acid residue, can occur at position Ser109, Thr126, Ser199, Ser274, Thr281, Ser298, Ser299, and/or Thr301 of the amino acid sequence of sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), variants thereof (SEQ ID NO: 4), and sFGFR3 polypeptides including a signal peptide (SEQ ID NO: 18 or 34). Additionally, O-linked glycosylation can occur at position Ser310 and/or Ser321 of sFGFR3_Del4-D3 (SEQ ID NO: 33) and variants thereof (SEQ ID NO: 4). One or more of these Ser or Thr residues can also be substituted to remove the glycosylation site.
(33) sFGFR3 Fusion Polypeptides
(34) sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be fused to a functional domain from a heterologous polypeptide (e.g., a fragment crystallizable region of an immunoglobulin (Fc region; such as a polypeptide having the amino acid sequence of SEQ ID NOs: 25 and 26) or human serum albumin (HSA; such as a polypeptide having the amino acid sequence of SEQ ID NO: 27)) to provide a sFGFR3 fusion polypeptide. Optionally, a flexible linker, can be included between the sFGFR3 polypeptide and the heterologous polypeptide (e.g., an Fc region or HSA), such as a serine or glycine-rich sequence (e.g., a poly-glycine or a poly-glycine/serine linker, such as SEQ ID NOs: 28 and 29).
(35) For example, the sFGFR3 polypeptides (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be a fusion polypeptide including, e.g., an Fc region of an immunoglobulin at the N-terminal or C-terminal domain. In particular, useful Fc regions can include the Fc fragment of any immunoglobulin molecule, including IgG, IgM, IgA, IgD, or IgE and their various subclasses (e.g., IgG-1, IgG-2, IgG-3, IgG-4, IgA-1, IgA-2) from any mammal (e.g., a human). For instance, the Fc fragment human IgG-1 (SEQ ID NO: 25) or a variant of human IgG-1, such as a variant including a substitution of asparagine at position 297 of SEQ ID NO: 25 with alanine (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 26). The Fc fragments of the invention can include, for example, the CH2 and CH3 domains of the heavy chain and any portion of the hinge region. The sFGFR3 fusion polypeptides of the invention can also include, e.g., a monomeric Fc, such as a CH2 or CH3 domain. The Fc region may optionally be glycosylated at any appropriate one or more amino acid residues known to those skilled in the art. An Fc fragment as described herein may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 50, or more additions, deletions, or substitutions relative to any of the Fc fragments described herein.
(36) Additionally, the sFGFR3 polypeptides (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be conjugated to other molecules at the N-terminal or C-terminal domain for the purpose of improving the solubility and stability of the protein in aqueous solution. Examples of such molecules include human serum albumin (HSA), PEG, PSA, and bovine serum albumin (BSA). For instance, the sFGFR3 polypeptides can be conjugated to human HSA (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 27) or a fragment thereof.
(37) The sFGFR3 fusion polypeptides can include a peptide linker region between the sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) and the heterologous polypeptide (e.g., an Fc region or HSA). The linker region may be of any sequence and length that allows the sFGFR3 to remain biologically active, e.g., not sterically hindered. Exemplary linker lengths are between 1 and 200 amino acid residues, e.g., 1-5, 6-10, 11-15, 16-20, 21-25, 26-30, 31-35, 36-40, 41-45, 46-50, 51-55, 56-60, 61-65, 66-70, 71-75, 76-80, 81-85, 86-90, 91-95, 96-100, 101-110, 111-120, 121-130, 131-140, 141-150, 151-160, 161-170, 171-180, 181-190, or 191-200 amino acid residues. For instance, linkers include or consist of flexible portions, e.g., regions without significant fixed secondary or tertiary structure. Preferred ranges are 5 to 25 and 10 to 20 amino acids in length. Such flexibility is generally increased if the amino acids are small and do not have bulky side chains that impede rotation or bending of the amino acid chain. Thus, preferably the peptide linker of the present invention has an increased content of small amino acids, in particular of glycines, alanines, serines, threonines, leucines and isoleucines.
(38) Exemplary flexible linkers are glycine-rich linkers, e.g., containing at least 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or even 100% glycine residues. Linkers may also contain, e.g., serine-rich linkers, e.g., containing at least 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or even 100% serine residues. In some cases, the amino acid sequence of a linker consists only of glycine and serine residues. For example, the linker can be the amino acid sequence of GGGGAGGGG (SEQ ID NO: 28) or GGGGSGGGGSGGGGS (SEQ ID NO: 29). A linker can optionally be glycosylated at any appropriate one or more amino acid residues. The linker can also be absent, in which the FGFR3 polypeptide and the heterologous polypeptide (e.g., an Fc region or HSA) are fused together directly, with no intervening residues.
(39) Polynucleotides Encoding the sFGFR3 Polypeptides
(40) The invention further includes polynucleotides encoding the sFGFR3 polypeptides (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) that can be used to treat skeletal growth retardation disorders (e.g., achondroplasia) in a patient (e.g., a human, such as an infant, a child, or an adolescent), such as SEQ ID NOs: 20, 21, 36, or 37. For example, the polynucleotide can be the nucleic acid sequence of SEQ ID NO: 20 or 36, which encode sFGFR3_Del4-C253S (SEQ ID NO: 2), or a variant having at least 85% sequence identity (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) to the nucleic acid sequence of SEQ ID NO: 20 or 36. Additionally, the polynucleotide can be the nucleic acid sequence of SEQ ID NO: 21 or 37, which encodes sFGFR3_Del4-D3 (SEQ ID NO: 33), having at least 85% sequence identity (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more sequence identity) to the nucleic acid sequence of SEQ ID NO: 21 or 37. The invention also includes polynucleotides encoding sFGFR3 fusion polypeptides (e.g., a sFGFR3 polypeptide fused to a heterologous polypeptide, such as a Fc region or HSA) and polynucleotides encoding sFGFR3 polypeptides without a signal peptide (e.g., polypeptides having the amino acid sequence of SEQ ID NOs: 2, 4, and 33) or with a signal peptide (e.g., polypeptides having the amino acid sequence of SEQ ID NOs: 18, 19, and 34). Additionally, the invention includes polynucleotides include one or more mutations to alter any of the glycosylation sites described herein.
(41) Optionally, the sFGFR3 polynucleotides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be codon optimized to alter the codons in the nucleic acid, in particular to reflect the typical codon usage of the host organism (e.g., a human) without altering the sFGFR3 polypeptide encoded by the nucleic acid sequence of the polynucleotide. Codon-optimized polynucleotides (e.g., a polynucleotide having the nucleic acid sequence of SEQ ID NO: 20, 21, 36, or 37) can, e.g., facilitate genetic manipulations by decreasing the GC content and/or for expression in a host cell (e.g., a HEK 293 cell or a CHO cell). Codon-optimization can be performed by the skilled person, e.g. by using online tools such as the JAVA Codon Adaption Tool (www.jcat.de) or Integrated DNA Technologies Tool (www.eu.idtdna.com/CodonOpt) by simply entering the nucleic acid sequence of the polynucleotide and the host organism for which the codons are to be optimized. The codon usage of different organisms is available in online databases, for example, www.kazusa.or.jp/codon.
(42) Host Cells for Expression of the sFGFR3 Polypeptides
(43) Mammalian cells can be used as host cells for expression of the sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Exemplary mammalian cell types useful in the methods include, but are not limited to, human embryonic kidney (HEK; e.g., HEK 293) cells, Chinese Hamster Ovary (CHO) cells, L cells, C127 cells, 3T3 cells, BHK cells, COS-7 cells, HeLa cells, PC3 cells, Vero cells, MC3T3 cells, NSO cells, Sp2/0 cells, VERY cells, BHK, MDCK cells, W138 cells, BT483 cells, Hs578T cells, HTB2 cells, BT20 cells, T47D cells, NSO cells, CRL7O3O cells, and HsS78Bst cells, or any other suitable mammalian host cell known in the art. Alternatively, E. coli cells can be used as host cells for expression of the sFGFR3 polypeptides. Examples of E. coli strains include, but are not limited to, E. coli 294 (ATCC®31,446), E. coli A 1776 (ATCC®31,537, E. coli BL21 (DE3) (ATCC® BAA-1025), E. coli RV308 (ATCC®31,608), or any other suitable E. coli strain known in the art.
(44) Vectors Including Polynucleotides Encoding the sFGFR3 Polypeptides
(45) The invention also features recombinant vectors including any one or more of the polynucleotides described above. The vectors of the invention can be used to deliver a polynucleotide encoding a sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), which can include mammalian, viral, and bacterial expression vectors. For example, the vectors can be plasmids, artificial chromosomes (e.g. BAG, PAC, and YAC), and virus or phage vectors, and may optionally include a promoter, enhancer, or regulator for the expression of the polynucleotide. The vectors can also contain one or more selectable marker genes, such as an ampicillin, neomycin, and/or kanamycin resistance gene in the case of a bacterial plasmid or a resistance gene for a fungal vector. Vectors can be used in vitro for the production of DNA or RNA or used to transfect or transform a host cell, such as a mammalian host cell for the production of a sFGFR3 polypeptide encoded by the vector. The vectors can also be adapted to be used in vivo in a method of gene therapy.
(46) Exemplary viral vectors that can be used to deliver a polynucleotide encoding a sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) include a retrovirus, adenovirus (e.g., Ad2, Ad5, Ad11, Ad12, Ad24, Ad26, Ad34, Ad35, Ad40, Ad48, Ad49, Ad50, and Pan9 (also known as AdC68)), parvovirus (e.g., adeno-associated viruses), coronavirus, negative strand RNA viruses such as orthomyxovirus (e.g., influenza virus), rhabdovirus (e.g., rabies and vesicular stomatitis virus), paramyxovirus (e.g. measles and Sendai), positive strand RNA viruses, such as picornavirus and alphavirus, and double stranded DNA viruses including adenovirus, herpesvirus (e.g., Herpes Simplex virus types 1 and 2, Epstein-Barr virus, cytomegalovirus), and poxvirus (e.g., vaccinia, modified vaccinia Ankara (MVA), fowlpox and canarypox). Other viruses useful for delivering polynucleotides encoding sFGFR3 polypeptides include Norwalk virus, togavirus, flavivirus, reoviruses, papovavirus, hepadnavirus, and hepatitis virus. Examples of retroviruses include avian leukosis-sarcoma, mammalian C-type, B-type viruses, D-type viruses, HTLV-BLV group, lentivirus, and spumavirus (Coffin, J. M., Retroviridae: The viruses and their replication, In Fundamental Virology, Third Edition, B. N. Fields, et al., Eds., Lippincott-Raven Publishers, Philadelphia, 1996).
(47) Methods of Production
(48) Polynucleotides encoding sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be produced by any method known in the art. For instance, a polynucleotide is generated using molecular cloning methods and is placed within a vector, such as a plasmid, an artificial chromosome, a viral vector, or a phage vector. The vector is used to transform the polynucleotide into a host cell appropriate for the expression of the sFGFR3 polypeptide.
(49) Nucleic Acid Vector Construction and Host Cells
(50) The sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be produced from a host cell. The polynucleotides (e.g., polynucleotides having the nucleic acid sequence of SEQ ID NO: 20, 21, 36, or 37 and variants thereof) encoding sFGFR3 polypeptides can be included in vectors that can be introduced into the host cell by conventional techniques known in the art (e.g., transformation, transfection, electroporation, calcium phosphate precipitation, direct microinjection, or infection). The choice of vector depends in part on the host cells to be used. Generally, host cells are of either prokaryotic (e.g., bacterial) or eukaryotic (e.g., mammalian) origin.
(51) A polynucleotide encoding an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be prepared by a variety of methods known in the art. These methods include, but are not limited to, oligonucleotide-mediated (or site-directed) mutagenesis and PCR mutagenesis. A polynucleotide encoding an sFGFR3 polypeptide can be obtained using standard techniques, e.g., gene synthesis. Alternatively, a polynucleotide encoding a wild-type sFGFR3 polypeptide (e.g., a polypeptide having the amino acid sequence of SEQ ID NO: 5 or 32) can be mutated to contain specific amino acid substitutions (e.g., an amino acid substitution of a cysteine residue with a serine residue or a conservative amino acid substitution, such as alanine, glycine, proline, or threonine, at position 253 of SEQ ID NO: 33 and/or position 316 of SEQ ID NO: 4) using standard techniques in the art, e.g., QuikChange™ mutagenesis. Polynucleotides encoding an sFGFR3 polypeptide can be synthesized using, e.g., a nucleotide synthesizer or PCR techniques.
(52) Polynucleotides encoding sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be inserted into a vector capable of replicating and expressing the polynucleotide in prokaryotic or eukaryotic host cells. Exemplary vectors useful in the methods can include, but are not limited to, a plasmid, an artificial chromosome, a viral vector, and a phage vector. For example, a viral vector can include the viral vectors described above, such as a retroviral vector, adenoviral vector, or poxviral vector (e.g., vaccinia viral vector, such as Modified Vaccinia Ankara (MVA)), adeno-associated viral vector, and alphaviral vector)) containing the nucleic acid sequence of a polynucleotide encoding the sFGFR3 polypeptide. Each vector can contain various components that may be adjusted and optimized for compatibility with the particular host cell. For example, the vector components may include, but are not limited to, an origin of replication, a selection marker gene, a promoter, a ribosome binding site, a signal sequence, the nucleic acid sequence of the polynucleotide encoding the sFGFR3 polypeptide, and/or a transcription termination sequence.
(53) The above-described vectors may be introduced into appropriate host cells (e.g., HEK 293 cells or CHO cells) using conventional techniques in the art, e.g., transformation, transfection, electroporation, calcium phosphate precipitation, and direct microinjection. Once the vectors are introduced into host cells for the production of an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), host cells are cultured in conventional nutrient media modified as appropriate for inducing promoters, selecting transformants, or amplifying the polynucleotides (e.g. SEQ ID NOs: 20 and 21 and variants thereof) encoding the sFGFR3 polypeptide. Methods for expression of therapeutic proteins, such as sFGFR3 polypeptides, are known in the art, see, for example, Paulina Balbas, Argelia Lorence (eds.) Recombinant Gene Expression: Reviews and Protocols (Methods in Molecular Biology), Humana Press; 2nd ed. 2004 (Jul. 20, 2004) and Vladimir Voynov and Justin A. Caravella (eds.) Therapeutic Proteins: Methods and Protocols (Methods in Molecular Biology) Humana Press; 2nd ed. 2012 (Jun. 28, 2012), each of which is hereby incorporated by reference in its entirety.
(54) sFGFR3 Polypeptide Production, Recovery, and Purification
(55) Host cells (e.g., HEK 293 cells or CHO cells) used to produce the sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be grown in media known in the art and suitable for culturing of the selected host cells. Examples of suitable media for mammalian host cells include Minimal Essential Medium (MEM), Dulbecco's Modified Eagle's Medium (DMEM), Expi293™ Expression Medium, DMEM with supplemented fetal bovine serum (FBS), and RPMI-1640. Examples of suitable media for bacterial host cells include Luria broth (LB) plus necessary supplements, such as a selection agent, e.g., ampicillin. Host cells are cultured at suitable temperatures, such as from about 20° C. to about 39° C., e.g., from 25° C. to about 37° C., preferably 37° C., and CO.sub.2 levels, such as 5 to 10% (preferably 8%). The pH of the medium is generally from about 6.8 to 7.4, e.g., 7.0, depending mainly on the host organism. If an inducible promoter is used in the expression vector, sFGFR3 polypeptide expression is induced under conditions suitable for the activation of the promoter.
(56) An sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be recovered from the supernatant of the host cell. Alternatively, the sFGFR3 polypeptide can be recovered by disrupting the host cell (e.g., using osmotic shock, sonication, or lysis), followed by centrifugation or filtration to remove the sFGFR3 polypeptide. Upon recovery of the sFGFR3 polypeptide, the sFGFR3 polypeptide can then be further purified. An sFGFR3 polypeptide can be purified by any method known in the art of protein purification, such as protein A affinity, other chromatography (e.g., ion exchange, affinity, and size-exclusion column chromatography), centrifugation, differential solubility, or by any other standard technique for the purification of proteins (see Process Scale Purification of Antibodies, Uwe Gottschalk (ed.) John Wiley & Sons, Inc., 2009, hereby incorporated by reference in its entirety).
(57) Optionally, the sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be conjugated to a detectable label for purification. Examples of suitable labels for use in purification of the sFGFR3 polypeptides include, but are not limited to, a protein tag, a fluorophore, a chromophore, a radiolabel, a metal colloid, an enzyme, or a chemiluminescent, or bioluminescent molecule. In particular, protein tags that are useful for purification of the sFGFR3 polypeptides can include, but are not limited to, chromatography tags (e.g., peptide tags consisting of polyanionic amino acids, such as a FLAG-tag, or a hemagglutinin “HA” tag), affinity tags (e.g., a poly(His) tag, chitin binding protein (CBP), maltose binding protein (MBP), or glutathione-S-transferase (GST)), solubilization tags (e.g., thioredoxin (TRX) and poly(NANP)), epitope tags (e.g., V5-tag, Myc-tag, and HA-tag), or fluorescence tags (e.g., GFP, GFP variants, RFP, and RFP variants).
(58) Methods of Treatment
(59) Provided herein are methods for treating a skeletal growth retardation disorder in a patient, such as a patient having achondroplasia (e.g., a human having achondroplasia). In particular, the patient is one that exhibits or is likely to develop one or more symptoms of a skeletal growth retardation disorder (e.g., achondroplasia). The method involves administering an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) to the patient having a skeletal growth retardation disorder, such as a patient having achondroplasia (e.g., a human having achondroplasia). In particular, the method involves administering sFGFR3_Del4-C253S (SEQ ID NO: 2) or sFGFR3_Del4-D3 (SEQ ID NO: 33) to the patient having a skeletal growth retardation disorder, such as a patient having achondroplasia (e.g., a human having achondroplasia). For example, the patient is an infant or child having a skeletal growth retardation disorder, such as an infant, a child, or an adolescent having achondroplasia (e.g., a human having achondroplasia).
(60) The patient (e.g., a human) can be treated before symptoms of a skeletal growth retardation disorder (e.g., achondroplasia) appear or after symptoms of a skeletal growth retardation disorder (e.g., achondroplasia) develop. In particular, patients that can be treated with a sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) are those exhibiting symptoms including, but not limited to, short limbs, short trunk, bowlegs, a waddling gait, skull malformations, cloverleaf skull, craniosynostosis, wormian bones, anomalies of the hands, anomalies of the feet, hitchhiker thumb, and/or chest anomalies. Furthermore, treatment with an sFGFR3 polypeptide can result in an improvement in one or more of the aforementioned symptoms of a skeletal growth retardation disorder (e.g., relative to an untreated patient), such as achondroplasia.
(61) The patient (e.g., a human) can be diagnosed with a skeletal growth retardation disorder, such as achondroplasia, before administration of an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Additionally, the patient having a skeletal growth retardation disorder, such as achondroplasia, can be one that has not previously been treated with an sFGFR3 polypeptide.
(62) Skeletal Growth Retardation Disorders
(63) Skeletal growth retardation disorders can be treated by administering an sFGFR3 polypeptide as described herein to a patient (e.g., a human) in need thereof. The method involves administering to the patient (e.g., a human) having the skeletal growth retardation disorder an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Skeletal growth retardation disorders that can be treated with the sFGFR3 polypeptides are characterized by deformities and/or malformations of the bones and can include, but are not limited to, FGFR3-related skeletal diseases. In particular, the patient is treated with sFGFR3_Del4-C253S (SEQ ID NO: 2) or sFGFR3_Del4-D3 (SEQ ID NO: 33).
(64) Administration of an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can treat a skeletal growth retardation disorder including, but not limited to, achondroplasia, achondrogenesis, acrodysostosis, acromesomelic dysplasia, atelosteogenesis, camptomelic dysplasia, chondrodysplasia punctata, rhizomelic type of chondrodysplasia punctata, cleidocranial dysostosis, congenital short femur, Crouzon syndrome, Apert syndrome, Jackson-Weiss syndrome, Pfeiffer syndrome, Crouzonodermoskeletal syndrome, dactyly, brachydactyly, camptodactyly, polydactyly, syndactyly, diastrophic dysplasia, dwarfism, dyssegmental dysplasia, enchondromatosis, fibrochondrogenesis, fibrous dysplasia, hereditary multiple exostoses, hypophosphatasia, hypophosphatemic rickets, Jaffe-Lichtenstein syndrome, Kniest dysplasia, Kniest syndrome, Langer-type mesomelic dysplasia, Marfan syndrome, McCune-Albright syndrome, micromelia, metaphyseal dysplasia, Jansen-type metaphyseal dysplasia, metatrophic dysplasia, Morquio syndrome, Nievergelt-type mesomelic dysplasia, neurofibromatosis (such as type 1 (e.g., with bone manifestations or without bone manifestations), type 2, or schwannomatosis), osteoarthritis, osteochondrodysplasia, osteogenesis imperfecta, perinatal lethal type of osteogenesis imperfecta, osteopetrosis, osteopoikilosis, peripheral dysostosis, Reinhardt syndrome, Roberts syndrome, Robinow syndrome, short-rib polydactyly syndromes, short stature, spondyloepiphyseal dysplasia congenita, and spondyloepimetaphyseal dysplasia.
(65) For instance, the sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be used to treat symptoms associated with a skeletal growth retardation disorder, including the disorders described above, such as achondroplasia. Non-limiting examples of symptoms of skeletal growth retardation disorders that can be treated with the sFGFR3 polypeptides, include short limbs and trunk, bowlegs, a waddling gait, skull malformations (e.g., a large head), cloverleaf skull, craniosynostosis (e.g., premature fusion of the bones in the skull), wormian bones (e.g., abnormal thread-like connections between the bones in the skull), anomalies of the hands and feet (e.g., polydactyly or extra fingers), “hitchhiker” thumbs and abnormal fingernails and toenails, and chest anomalies (e.g., pear-shaped chest or narrow thorax). Additional symptoms that can treated by administering sFGFR3 polypeptides can also include non-skeletal abnormalities in patients having skeletal growth retardation disorders, such as anomalies of the eyes, mouth, and ears, such as congenital cataracts, myopia, cleft palate, or deafness; brain malformations, such as hydrocephaly, porencephaly, hydranencephaly, or agenesis of the corpus callosum; heart defects, such as atrial septal defect, patent ductus arteriosus, or transposition of the great vessels; developmental delays; or mental disabilities.
(66) Treatment with the sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can also increase survival of patients (e.g., humans) with skeletal growth retardation disorders (e.g., achondroplasia). For example, the survival rate of patients treated with the sFGFR3 polypeptides can increase by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or more relative to, e.g., an untreated patient with a skeletal growth retardation disorder (e.g., achondroplasia), over a treatment period of days, months, years, or longer. In particular, administration of sFGFR3_Del4-D3 can increase survival of patients (e.g., humans) with skeletal growth retardation disorders (e.g., relative to an untreated patient), such as achondroplasia.
(67) Any skeletal growth retardation disorder that is a FGFR3-related skeletal disease (e.g., caused by or associated with overactivation of FGFR3 as result of a gain-of-function FGFR3 mutation) can be treated by administering an sFGFR3 polypeptide of the invention ((e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) to a patient (e.g., a human). For example, FGFR3-related skeletal diseases can include, but are not limited to, achondroplasia, thanatophoric dysplasia type I (TDI), thanatophoric dysplasia type II (TDII), severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN), hypochondroplasia, and craniosynostosis (e.g., Muenke syndrome, Crouzon syndrome, and Crouzonodermoskeletal syndrome).
(68) Patients (e.g., humans) with mutations in the FGFR3 gene associated with different FGFR3-related skeletal disorders, such as achondroplasia, hypochondroplasia, SADDAN, TDI, and TDII, can be treated with sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). For example, the sFGFR3 polypeptides can be administered to treat achondroplasia resulting from the G380R, G375C, G346E or S279C mutations of the FGFR3 gene. Administration of the sFGFR3 polypeptides can be used to treat the following exemplary FGFR3-related skeletal disorders: hypochondroplasia resulting from the G375C, G346E or S279C mutations of the FGFR3 gene; TDI resulting from the R248C, S248C, G370C, S371C, Y373C, X807R, X807C, X807G, X8075, X807W and K650M mutations of the FGFR3 gene; TDII resulting from the K650E mutation of the FGFR3 gene; and SADDAN resulting from the K650M mutation of the FGFR3 gene.
(69) Any of the aforementioned mutations in the FGFR3 gene (e.g., the G380R mutation of the FGFR3 gene) can be detected in a sample from the patient (e.g., a human with achondroplasia, hypochondroplasia, SADDAN, TDI, and TDII) prior to or after treatment with an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Additionally, the parents of the patient and/or fetal samples (e.g., fetal nucleic acid obtained from maternal blood, placental, or fetal samples) can be tested by methods known in the art for the mutation in the FGFR3 gene to determine their need for treatment.
(70) Achondroplasia
(71) Achondroplasia is the most common cause of dwarfism in humans and can be treated by administering sFGFR3 polypeptides as described herein. In particular, achondroplasia can be treated by administering an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Accordingly, administration of the sFGFR3 polypeptides can result in an improvement in symptoms including, but not limited to, growth retardation, skull deformities, orthodontic defects, cervical cord compression (with risk of death, e.g., from central apnea or seizures), spinal stenosis (e.g., leg and lower back pain), hydrocephalus (e.g., requiring cerebral shunt surgery), hearing loss due to chronic otitis, cardiovascular disease, neurological disease, respiratory problems, fatigue, pain, numbness in the lower back and/or spine, and/or obesity.
(72) Patients treated using the sFGFR3 polypeptides of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can include infants, children, and adults with achondroplasia. In particular, infants are often diagnosed with achondroplasia at birth, and thus, treatment with the sFGFR3 polypeptides can begin as early as possible in the patient's life, e.g., shortly after birth, or prior to birth (in utero).
(73) Symptoms of achondroplasia in patients (e.g., humans) can also be monitored prior to or after a patient is treated with an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). For instance, symptoms of achondroplasia can be monitored prior to treatment to assess the severity of achondroplasia and condition of the patient prior to performing the methods.
(74) The methods can include diagnosis of achondroplasia in a patient and monitoring the patient for changes in the symptoms of achondroplasia, such as changes in body weight and skull size (e.g., skull length and/or skull width) of the patient. Changes in body weight and skull size can be monitored over a period of time, e.g., 1, 2, 3, 4 or more times per month or per year or approximately every 1, 2, 3, 4, 5, 6, 7, 8, 12 or 16 weeks over the course of treatment with the sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Body weight and/or skull size of the patient having achondroplasia can also be determined at treatment specific events, such as before and/or after administration of the sFGFR3 polypeptide.
(75) For example, body weight and/or skull size can be measured in response to administration of the sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)). Body weight can be measured by weighing the patient having achondroplasia on a scale, preferably in a standardized manner, such as with the same or no clothes or at a certain time of the day, preferably in a fasting state (e.g., in the morning before breakfast or after at least 1, 2, 3, 4, 5 or more hours of fasting). Skull size can be represented by length, height, width, and/or circumference of the skull. Measurements can be performed using any known or self-devised standardized method. For a human subject, the measurement of skull circumference is preferred, which can be measured using a flexible and non-stretchable material, such as a tape, wrapped around the widest possible circumference of the head (e.g. from the most prominent part of the forehead around to the widest part of the back of the head). The height of the skull of the subject (e.g., human) can also be determined from the underside of the chin to the uppermost point of the head. Preferably, any measurement is performed more than once, e.g. at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more times.
(76) Administration of sFGFR3 Polypeptides
(77) An sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be administered by any route known in the art, such as by parenteral administration, enteral administration, or topical administration. In particular, the sFGFR3 polypeptide can be administered to the patient having a skeletal growth retardation disorder (e.g., achondroplasia) subcutaneously (e.g., by subcutaneous injection), intravenously, intramuscularly, intra-arterially, intrathecally, or intraperitoneally.
(78) An sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be administered to a patient (e.g., a human) at a predetermined dosage, such as in an effective amount to treat a skeletal growth retardation disorder (e.g., achondroplasia), without inducing significant toxicity. For example, sFGFR3 polypeptides can be administered to a patient having skeletal growth retardation disorders (e.g., achondroplasia) in individual doses ranging from about 0.002 mg/kg to about 50 mg/kg (e.g., from 2.5 mg/kg to 30 mg/kg, from 0.002 mg/kg to 20 mg/kg, from 0.01 mg/kg to 2 mg/kg, from 0.2 mg/kg to 20 mg/kg, from 0.01 mg/kg to 10 mg/kg, from 10 mg/kg to 100 mg/kg, from 0.1 mg/kg to 50 mg/kg, 0.5 mg/kg to 20 mg/kg, 1.0 mg/kg to 10 mg/kg, 1.5 mg/kg to 5 mg/kg, or 0.2 mg/kg to 3 mg/kg). In particular, the sFGFR3 polypeptide can be administered in individual doses of, e.g., 0.001 mg/kg to 50 mg/kg, such as 2.5 mg/kg to about 10 mg/kg.
(79) Exemplary doses of an sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) for administration to a patient (e.g., a human) having a skeletal growth retardation disorder (e.g., achondroplasia) include, e.g., 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, or 50 mg/kg. These doses can be administered one or more times (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 or more times) per day, week, month, or year. For example, an sFGFR3 polypeptide can be administered to patients in a weekly dosage ranging, e.g., from about 0.0014 mg/kg/week to about 140 mg/kg/week, e.g., about 0.14 mg/kg/week to about 105 mg/kg/week, or, e.g., about 1.4 mg/kg/week to about 70 mg/kg/week (e.g., 2.5 mg/kg/week, 5 mg/kg/week, 10 mg/kg/week, 20 mg/kg/week, 30 mg/kg/week, 40 mg/kg/week, or 50 mg/kg/week).
(80) Gene Therapy
(81) An sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can also be delivered through gene therapy, where a polynucleotide encoding the sFGFR3 polypeptide is delivered to tissues of interest and expressed in vivo. Gene therapy methods are discussed, e.g., in Verme et al. (Nature 389: 239-242, 1997), Yamamoto et al. (Molecular Therapy 17: S67-S68, 2009), and Yamamoto et al., (J. Bone Miner. Res. 26: 135-142, 2011), each of which is hereby incorporated by reference.
(82) An sFGFR3 polypeptide of the invention (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)) can be produced by the cells of a patient (e.g., a human) having a skeletal growth retardation disorder (e.g., achondroplasia) by administrating a vector (e.g., a plasmid, an artificial chromosome (e.g. BAG, PAC, and YAC), or a viral vector) containing the nucleic acid sequence of a polynucleotide encoding the sFGFR3 polypeptide. For example, a viral vector can be a retroviral vector, adenoviral vector, or poxviral vector (e.g., vaccinia viral vector, such as Modified Vaccinia Ankara (MVA)), adeno-associated viral vector, or alphaviral vector. The vector, once inside a cell of the patient (e.g., a human) having a skeletal growth retardation disorder (e.g., achondroplasia), by, e.g., transformation, transfection, electroporation, calcium phosphate precipitation, or direct microinjection, will promote expression of the sFGFR3 polypeptide, which is then secreted from the cell. The invention further includes cell-based therapies, in which the patient (e.g., a human) is administered a cell expressing the sFGFR3 polypeptide.
(83) Pharmaceutical Compositions
(84) Pharmaceutical compositions of the invention can include an sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotide, vector, and/or host cell of the invention. Compositions including an sFGFR3 polypeptide, polynucleotide, vector, and/or host cell can be formulated at a range of dosages, in a variety of formulations, and in combination with pharmaceutically acceptable excipients, carriers, or diluents.
(85) A pharmaceutical composition including an sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotide, vector, and/or host cell of the invention can be formulated at a specific dosage, such as a dosage that is effective for treating a patient (e.g., a human) skeletal growth retardation disorder (e.g., achondroplasia), without inducing significant toxicity. For example, the compositions can be formulated to include between about 1 mg/mL and about 500 mg/mL of the sFGFR3 polypeptide (e.g., between 10 mg/mL and 300 mg/mL, 20 mg/mL and 120 mg/mL, 40 mg/mL and 200 mg/mL, 30 mg/mL and 150 mg/mL, 40 mg/mL and 100 mg/mL, 50 mg/mL and 80 mg/mL, or 60 mg/mL and 70 mg/mL of the sFGFR3 polypeptide).
(86) The pharmaceutical compositions including an sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotide, vector, and/or host cell of the invention can be prepared in a variety of forms, such as a liquid solution, dispersion or suspension, powder, or other ordered structure suitable for stable storage. For example, compositions including an sFGFR3 polypeptide intended for systemic or local delivery can be in the form of injectable or infusible solutions, such as for parenteral administration (e.g., subcutaneous, intravenous, intramuscular, intra-arterial, intrathecal, or intraperitoneal administration). sFGFR3 compositions for injection (e.g., subcutaneous or intravenous injection) can be formulated using a sterile solution or any pharmaceutically acceptable liquid as a vehicle. Pharmaceutically acceptable vehicles include, but are not limited to, sterile water, physiological saline, and cell culture media (e.g., Dulbecco's Modified Eagle Medium (DMEM), α-Modified Eagles Medium (α-MEM), F-12 medium). Formulation methods are known in the art, see e.g., Banga (ed.) Therapeutic Peptides and Proteins: Formulation, Processing and Delivery Systems (2nd ed.) Taylor & Francis Group, CRC Press (2006), which is hereby incorporated by reference in its entirety.
(87) Compositions including an sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotide, vector, and/or host cell of the invention can be provided to patients (e.g., humans) having skeletal growth retardation disorders (e.g. achondroplasia) in combination with pharmaceutically acceptable excipients, carriers, or diluents. Acceptable excipients, carriers, or diluents can include buffers, antioxidants, preservatives, polymers, amino acids, and carbohydrates. Aqueous excipients, carriers, or diluents can include water, water-alcohol solutions, emulsions or suspensions including saline, buffered medical parenteral vehicles including sodium chloride solution, Ringer's dextrose solution, dextrose plus sodium chloride solution, Ringer's solution containing lactose, and fixed oils. Examples of non-aqueous excipients, carriers, or diluents are propylene glycol, polyethylene glycol, vegetable oil, fish oil, and injectable organic esters.
(88) Pharmaceutically acceptable salts can also be included in the compositions including an sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotide, vector, and/or host cell of the invention. Exemplary pharmaceutically acceptable salts can include mineral acid salts (e.g., hydrochlorides, hydrobromides, phosphates, and sulfates) and salts of organic acids (e.g., acetates, propionates, malonates, and benzoates). Additionally, auxiliary substances, such as wetting or emulsifying agents and pH buffering substances, can be present. A thorough discussion of pharmaceutically acceptable excipients, carriers, and diluents is available in Remington: The Science and Practice of Pharmacy, 22.sup.nd Ed., Allen (2012), which is hereby incorporated by reference in its entirety.
(89) Pharmaceutical compositions including an sFGFR3 polypeptide (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotide, vector, and/or host cell of the invention can also be formulated with a carrier that will protect the sFGFR3 polypeptide against rapid release, such as a controlled release formulation, including implants and microencapsulated delivery systems. For example, the sFGFR3 composition can be entrapped in microcapsules prepared by coacervation techniques or by interfacial polymerization, such as hydroxymethylcellulose, gelatin, or poly-(methylmethacylate) microcapsules; colloidal drug delivery systems (e.g., liposomes, albumin microspheres, microemulsions, nano-particles, or nanocapsules); or macroemulsions. Additionally, an sFGFR3 composition can be formulated as a sustained-release composition. For example, sustained-release compositions can include semi-permeable matrices of solid hydrophobic polymers containing the sFGFR3 polypeptides, polynucleotides, vectors, or host cells of the invention, in which the matrices are in the form of shaped articles, such as films or microcapsules.
(90) Kits
(91) Kits of the invention can include one or more sFGFR3 polypeptides (e.g. sFGFR3_Del4-C253S (SEQ ID NO: 2), sFGFR3_Del4-D3 (SEQ ID NO: 33), and variants thereof (SEQ ID NO: 4) or a sFGFR3 polypeptide including a signal peptide (SEQ ID NO: 18 or 34)), polynucleotides, vectors, and/or cells of the invention as described herein. For example, the sFGFR3 polypeptide, polynucleotide, vector, and/or cell can be present in a container (e.g., a glass vial) in liquid form (e.g., in water or a buffered salt solution, such as, 2 mM to 20 mM of sodium phosphate, pH 6.5 or 7.0, and 25 mM to 250 mM sodium chloride). Alternatively, the sFGFR3 polypeptide, polynucleotide, and/or vector is present in a container (e.g., a glass vial) in lyophilized form, which can optionally include a diluent (e.g., water or a buffered salt solution) for reconstitution of the lyophilized sFGFR3 polypeptide, polynucleotide, vector, and/or cell into liquid form prior to administration. The sFGFR3 polypeptide, polynucleotide, vector, and/or cell can also be present in a kit in another formulation as described herein. The kit components can be provided in dosage form to facilitate administration, and optionally, can include materials required for administration and/or instructions for patient treatment consistent with the methods. For example, the kit can include instructions for use, which guides the user (e.g., the physician) with respect to the administration of the sFGFR3 polypeptide, polynucleotide, vector, and/or cell.
EXAMPLES
(92) The following examples are intended to illustrate, rather than limit, the disclosure. These studies feature the administration of the sFGFR3 polypeptides of sFGFR3_Del4-C253S (SEQ ID NO: 2) and sFGFR3_Del4-D3 (SEQ ID NO: 33) to patients (e.g., humans) having achondroplasia, to treat achondroplasia and symptoms associated therewith.
Example 1: Production of sFGFR3 Polypeptides
(93) sFGFR3_Del4-C253S (SEQ ID NO: 2) and sFGFR3_Del4-D3 (SEQ ID NO: 33) were produced by transient transfection in three different suspension cell types: HEK 293 freestyle, CHO—S freestyle cells and Expi CHO—S cells. For production in HEK 293 freestyle and CHO—S freestyle cells, transfection was performed using polyethylenimine (PEIpro®—Polyplus-transfection), according to the manufacturer's directions. Proteins were harvested after three days. For sFGFR3 polypeptide production in Expi CHO—S cells, transfection was performed using Expifectamine as described by the manufacturer using the High Titer production protocol. A time course was performed and sFGFR3 polypeptides were optimally harvested after 12 days. Western blots were then performed using 50 ng of sFGFR3 polypeptide. Classical western blot protocols were used with B9 as a primary antibody (anti FGFR3, sc-13121, Santa Cruz) diluted 1:2000 in blocking buffer and anti-mouse IgG secondary antibody (Anti-mouse IgG, #7076, Cell signaling) diluted 1:5000 in blocking buffer.
Example 2: Purification of sFGFR3 Polypeptides
(94) sFGFR3_Del4-C253S and sFGFR3_Del4-D3 were each purified using a two-step purification process including ion exchange chromatography and size exclusion chromatography.
(95) For ion exchange chromatography, 300 mL of culture supernatant was purified by cross flow filtration (ÄKTA™ flux, GE Healthcare) using 5 μm and 0.2 μm capsules (KGF-A0504 TT and KMP-HEC 9204 TT, GE Healthcare, respectively). The purified sample including sFGFR3_Del4-C253S or sFGFR3_Del4-D3 was then loaded on an equilibrated column at 20 mL/min, after adjusting the sample's conductivity to 14 mS/cm (ÄKTA™ pure 25 (GE Healthcare)). Columns used were HiPrep Q FF 26/10 (GE Healthcare) with a bed volume of 53 mL. The binding buffer was 1×PBS and the elution buffer was PBS 1×+1 M NaCl. The column was washed with four column volumes of 1×PBS. Elution of sFGFR3_Del4-C253S and sFGFR3_Del4-D3 was performed by two steps of 5% NaCl and 10% NaCl using four column volumes of each. Both 5% NaCl and 10% NaCl were pooled and concentrated by cross flow filtration (ÄKTA™ flux, GE Healthcare). The remaining volume was then concentrated on a 30 kDa filter by centrifugation at 4° C., 3,900 g for 10 min (MILLLIPORE® UFC903024 AMICON® Ultra-15 Centrifugal Filter Concentrator). For size exclusion chromatography, the remaining volume was loaded on a HiLoad 26/600 SUPERDEX™ 200 prep grade (28-9893-36, GE Healthcare) with a bed volume of 320 mL. Loading volume did not exceed 12.8 mL. Elution was performed in 1×PBS.
Example 3: Kinetic Assays and Dissociation Constant (K.SUB.d.) Measurements of sFGFR3 Polypeptides
(96) Calibration Free Concentration Analysis and kinetic assays of sFGFR3_Del4-C253S and sFGFR3_Del4-D3 were performed with a Sensor Chip CM5 (GE Healthcare). Human FGF2 (hFGF2) was covalently immobilized to the Sensor Chip CM5 at a level of about 5000 RU by amine coupling. To achieve 5000 RU, hFGF2 was immobilized for 420 seconds at a flow rate 10 μI/min and a concentration 25 μg/ml. Running buffer was HBS-EP+ Buffer (GE Healthcare). Regeneration buffer was 100 mM sodium acetate with 2M sodium chloride pH 4.5. FGF binding, dissociation constant (K.sub.d) measurements, and kinetic parameters were determined by Surface Plasmon Resonance using a BIACORE™ T200 (GE Healthcare). The model used for kinetic assays and K.sub.d determination was a 1:1 binding algorithm.
Example 4: Proliferation Assays of sFGFR3 Polypeptides
(97) Both ATDC5 and ATDC5 FGFR3.sup.G380R cell lines were seeded at a density of 25,000 cells/cm.sup.2 in NUNC™ MICROWELL™ 96-Well Optical-Bottom Plates with Polymer Base (ThermoFisher Scientific, Catalog No. 165305). After a 24 hour incubation period, cells were depleted for 48 hour in 0.5% BSA and then stimulated for 72 hour with sFGFR3_Del4-C253S or sFGFR3_Del4-D3 with and without hFGF2 (Peprotech). Cell proliferation was then measured using the CyQUANT® Direct Cell Proliferation Assay (Molecular Probes, Catalog No. C35012). After stimulation, 10 μL of CyQUANT® Direct Cell Proliferation (Invitrogen; 1 mL 1×PBS, 250 μL background suppressor, and 50 μL nuclear stain) was added per well. ATDC5 and ATDC5 FGFR3.sup.G380R cells were then incubated at room temperature in the dark for 2 hours.
(98) Fluorescence was read using the VARIOSKAN™ LUX multimode microplate reader (ThermoFisher Scientific).
Example 5: Luciferase Assays of sFGFR3 Polypeptides
(99) Serum Response Element-Luciferase (SRE-Luc) HEK cells expressing FGFR3.sup.G380R were seeded at a density of 100,000 cells/cm.sup.2 in a standard culture 96 well plate. Cells were then depleted for 24 hours with 0.5% heat inactivated Fetal Bovine Serum (hiFBS), before being treated with sFGFR3_Del4-D3 at concentrations of 0 nm, 70 nm, and 280 nm with or without 1 ng/ml of hFGF2 for 24 h. The culture plate was equilibrated to room temperature for 15 minutes prior to adding 100 μL per well of Firefly Luc One-Step Glow Assay Working Solution (ThermoFisher Scientific, Catalog No. 16197), then shaken at 600 rpm for 3 minutes. The plate was incubated at room temperature for 10 minutes and each cell lysate was transferred to a white opaque 96 well plate to increase luminescence signal and decrease cross contamination. The luminescence signal was read using the VARIOSKAN™ LUX multimode microplate reader (Thermo Fisher Scientific).
Example 6: In Vivo Efficacy Study of sFGFR3 Polypeptides
(100) Experiments were performed on transgenic Fgfr3.sup.ach/+ animals in which expression of the mutant FGFR3 is driven by the Col2a1 promoter/enhancer. Mice were exposed to a 12 hour light/dark cycle and had free access to standard laboratory food and water. Genotypes were verified by PCR of genomic DNA using the primers 5′-AGGTGGCCTTTGACACCTACCAGG-3′ (SEQ ID NO: 30) and 5′-TCTGTTGTGTTTCCTCCCTGTTGG-3′ (SEQ ID NO: 31), which amplify 360 bp of the FGFR3 transgene.
(101) sFGFR3_Del4-D3 produced using CHO cells was evaluated at a subcutaneous dose of 0.25 mg/kg twice weekly. At day 3, all newborn mice from a single litter received the same dose. Control litters received 10 μl of PBS (vehicle). Thereafter, subcutaneous injections of sFGFR3_Del4-D3 (0.25 mg/kg) were administered twice a week for three weeks, alternatively on the left and right sides of the back. Mice were observed daily with particular attention to locomotion and urination alterations. Breeding was performed to generate litters with half wild type and half heterozygous Fgfr3.sup.ach/+ mice. To avoid bias due to phenotype penetrance variations, experiments were performed on at least two litters (one treated and one control) from the same breeders. Previous data indicated there was no statistical difference between males and females, and thus, males and females were considered one group for all analyses.
(102) At day 22, all animals were sacrificed by lethal injection of pentobarbital, and gender was determined. All subsequent measurements and analyses were performed without knowledge of mice genotype to avoid investigator bias. Genotyping was performed at the end of the study to reveal the correspondence of data with a specific genotype. Since achondroplasia is a disease with phenotypic variability, all animals were included in the study. Animals dead before day 22 were used to investigate the impact of treatment on premature death. Surviving animals at day 22 were used for all analyses. All experiments and data measurements were performed by blinded experimenters at all time points.
(103) Following sacrifice at day 22, body weights were measured. Cadavers were carefully skinned, eviscerated, and skeletal measurements were performed based on X-rays. Organs were harvested, weighed, and stored in 10% formalin for further histological analysis using standard paraffin-embedded techniques. Organs were then observed for macroscopic abnormalities, such as modification of color or texture and presence of nodules. The Principles of Laboratory Animal Care (NIH publication no. 85-23, revised 1985; grants1.nih.gov/grants/olaw/references/phspol.htm) and the European commission guidelines for the protection of animals used for scientific purposes (ec.europa.eu/environment/chemicals/lab_animals/legislation_en.htm) were followed during all animal experiments. All procedures were approved by the Institutional Ethic Committee for the use of Laboratory Animals (CIEPAL Azur) (approval #NCE-2012-52).
Example 7: The Cell Line Used to Produce sFGFR3 Polypeptides Did not Impact Activity
(104) The FGF2 binding activity, Kd, and effect on cellular signaling of sFGFR3_Del1 (SEQ ID NO: 7), sFGFR3_Del4 (SEQ ID NO: 1), and sFGFR3_Del4-LK1-LK2 (SEQ ID NO: 10) produced in suspension HEK 293 cells or CHO cells were compared. HEK 293 cells or CHO cells differ in post-translation modification of proteins. Expression of the sFGFR3 polypeptides in different cell lines did not impact Kd, binding activity, or the effect of the sFGFR3 polypeptides on intracellular signaling inhibition (
Example 8: Improved Production of sFGFR3_Del4-C2538 and sFGFR3_Del4-D3
(105) The sFGFR3 polypeptides of sFGFR3_Del1 (SEQ ID NO: 7), sFGFR3_Del4 (SEQ ID NO: 1), and sFGFR3_Del4-LK1-LK2 (SEQ ID NO: 10) were each modified to include either an amino acid substitution of a cysteine residue with a serine residue at position 253 or an extended Ig-like C2-type domain 3 (SEQ ID NO: 33). These modifications of sFGFR3_Del1 and sFGFR3_Del4-LK1-LK2 had no or minimal effect on production of the sFGFR3 polypeptides, since aggregation was still visible (
(106) Additionally, sFGFR3_Del4, sFGFR3_Del4-C253S, and sFGFR3_Del4-D3 exhibited similar Kd and were not affected by cell type specific changes in post translational modifications. In Expi CHO cells, the Kd of sFGFR3_Del4 was 0.8 nM, the Kd of sFGFR3_Del4-C253S was 0.6 nM, and the Kd of sFGFR3_Del4-D3 was 0.7 nM (
(107) TABLE-US-00001 TABLE 1 Dissociation constant (Kd) of sFGFR3 polypeptides. SFGFR3 Polypeptide Kd (nM) sFGFR3_Del4 0.8 sFGFR3_Del4-C253S 0.6 sFGFR3_Del4-D3 0.7
Example 9: sFGFR3_Del4-C253S and sFGFR3_Del4-D3 are Equally Active In Vitro
(108) sFGFR3_Del4, sFGFR3_Del4-C253S, and sFGFR3_Del4-D3 restored proliferation of ATDC5 cells genetically modified to overexpress the FGFR3.sup.ach mutation (ATDC5 FGFR3.sup.G380R cell lines). At a dose of 36 nM, sFGFR3_Del4 produced using HEK 293 cells increased proliferation to 115.5%, sFGFR3_Del4 produced using CHO—S cells increased proliferation to 116%, sFGFR3_Del4-C253S produced using CHO—S cells increased proliferation to 114.4%, and sFGFR3_Del4-D3 using CHO—S cells increased proliferation to 120.1% (
(109) sFGFR3_Del4-D3 was also tested in the FGFR3.sup.G380R expressing SRE(-Luc) HEK cell line at doses of 0 nM, 70 nM, and 280 nM with or without 1 ng/ml of hFGF2 (
Example 10: sFGFR3_Del4-D3 Restores Bone Growth, Prevents Mortality, and Restores Foramen Magnum Shape in Mice with Achondroplasia
(110) An in vivo efficacy study was performed as in Example 6 using a low dose (0.25 mg/kg) of sFGFR3_Del4-D3. A total of 60 mice were included in the vehicle group, with 32 wild type (wt) mice and 28 Fgfr3.sup.ach/+ mice. The treated group included 40 mice, with 19 wt mice and 21 Fgfr3.sup.ach/+ mice. Surprisingly, the low dose of sFGFR3_Del4-D3 almost completely prevented the premature death of mice with achondroplasia (
(111) sFGFR3_Del4-D3 also partially restored bone growth with correction of the initial discrepancy between wt and Fgfr3.sup.ach/+ mice on the axial and appendicular skeleton (Table 2). In contrast to prior results of treatment with a low dose of sFGFR3 Del1, treatment with low dose of sFGFR3_Del4-D3 restored normal foramen magnum shape.
(112) TABLE-US-00002 TABLE 2 In vivo results of administering a high dose of sFGFR3_Del1, a low dose of sFGFR3_Del1, and a low dose of sFGFR3_Del4-D3 to mice with achondroplasia 2.5 mg/kg 0.25 mg/kg sFGFR3_Del1 sFGFR3_Del1 0.25 mg/kg (Garcia et al.) (Garcia et al.) sFGFR3_Del4-D3 Mortality 12% 20% 4.8% Axial correction 77% 24% 10% Appendicular 150-215% 18-42% 11-42% correction Foramen shape Not Not 111% correction determined determined (ratio W/H)
Example 11: Treatment of Achondroplasia by Administration of sFGFR3_Del4-C253S
(113) A human patient (e.g., an infant, child, adolescent, or adult) suffering from achondroplasia can be treated by administering sFGFR3_Del4-C253S (
Example 12: Treatment of Achondroplasia by Administration of sFGFR3_Del4-D3
(114) Additionally, a human patient (e.g., an infant, child, adolescent, or adult) suffering from achondroplasia can be treated by administering the sFGFR3 polypeptide of sFGFR3_Del4-D3 (SEQ ID NO: 33) by an appropriate route (e.g., by subcutaneous injection) at a particular dosage (e.g., between 0.0002 mg/kg/day to about 20 mg/kg/day, such as 0.001 mg/kg/day to 7 mg/kg/day) over a course of days, weeks, months, or years. The progression of achondroplasia that is treated with sFGFR3_Del4-D3 can be monitored by one or more of several established methods. A physician can monitor the patient by direct observation in order to evaluate how the symptoms of achondroplasia exhibited by the patient have changed in response to treatment. For instance, a physician may monitor changes in body weight, skull length, and/or skull width of the patient over a period of time, e.g., 1, 2, 3, 4 or more times per month or per year or approximately every 1, 2, 3, 4, 5, 6, 7, 8, 12, or 16 weeks over the course of treatment with sFGFR3_Del4-D3. Body weight and/or skull size of the patient or changes thereof can also be determined at treatment specific events, e.g. before and/or after administration of sFGFR3_Del4-D3. For example, body weight and/or skull size are measured in response to administration of sFGFR3_Del4-D3.
Example 13: Production of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S
(115) The sFGFR3_Del4-D3 and sFGFR3_Del4-C253S polypeptides were purified as described in Example 2. Modification of sFGFR3 Del4 to include either an extended Ig-like C2-type domain 3 (FGFR3_Del4-D3) or an amino acid substitution of a cysteine residue with a serine residue at position 253 (sFGFR3_Del4-C253S) improved production of the sFGFR3 polypeptides. In particular, there was less than about 2% aggregation of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S (as observed upon loading using a concentration of 2.3 mg/ml or 23 mg/ml for FGFR3_Del4-D3 and 1.5 mg/ml and 15 mg/ml of sFGFR3_Del4-C253S) under both reducing and non-reducing conditions using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE;
Example 14: Pharmacokinetics and Tissue Distribution of sFGFR3_Del4-D3 In Vivo
(116) In vivo studies were performed to investigate the pharmacokinetic parameters of sFGFR3_Del4-D3, the uptake of sFGFR3_Del4-D3 across the blood brain barrier, and the tissue distribution of sFGFR3_Del4-D3 in kidney, liver, spleen, lung, and heart. The studies described herein included four arms with five groups of C57BL/6J mice per arm and a total of four mice (n=4) per group (Table 3). Mice were male and weighed 25 to 30 grams.
(117) TABLE-US-00003 TABLE 3 Overview of mice used in studies of sFGFR3_Del4-D3. sFGFR3_Del4- Tissue Arm D3 (mg/kg) Route PK BBB distribution 1 0.25 SC yes no no 2 2.5 SC yes no yes 3 2.5 IV yes Yes yes 4 10 SC yes no no
(118) Group 1 was sampled at 1 minute, 15 minutes, and 30 minutes; group 2 was sampled at 4 hours; group 3 was sampled at 24 hours; group 4 was sampled at 36 hours; and group 5 was sampled at 48 hours. For Group 1, an indwelling intra-arterial catheter (PE-10) was inserted into one common carotid artery under isoflurane anesthesia and used for repeated blood sampling at the 30 minute final sampling time point. For intravenous injection, .sup.125I-sFGFR3_Del4-D3 was injected intravenously into the jugular vein, which was exposed by skin incision under isoflurane anesthesia. Group 1 mice remained anesthetized throughout the experiments. Repeated blood samples (2×-50 μL) were drawn from the arterial catheter at 1 minute and 15 minutes after intravenous injection. For groups 2 to 5, after injection of .sup.125I-sFGFR3_Del4-D3, the skin was closed with a surgical clip, and the mice were allowed to wake up and returned to the cage. At 5 minutes before termination time for group 3, mice were re-anesthetized and received an intravenous bolus of .sup.3H-albumin into the jugular vein. The .sup.3H tracer dose was targeted to yield a ratio of .sup.125I to .sup.3H in blood, which is suitable for double isotope labeling with a lower dose at later sampling times. At the terminal sampling time (2 hours, 3 hours, 24 hours, 36 hours, and 48 hours), a blood sample was collected, and the animal was euthanized. The brain was sampled for homogenization and determination of tissue concentration of tracers. Endpoints of the studies included pharmacokinetic parameters for sFGFR3_Del4-D3 (terminal half life), uptake of sFGFR3_Del4-D3 across the blood brain barrier, and the tissue distribution of sFGFR3_Del4-D3 in kidney, liver, spleen, lung, and heart.
Example 15: Thermal and Plasma Stability of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S
(119) The thermal stability of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S in mouse plasma was investigated using differential scanning colorimetry. For sFGFR3_Del4-D3, two buffers (20 mM phosphate, 40 mM NaCl, pH 7.5, and 20 mM citrate, 40 mM NaCl, pH 6.5) were added to polypeptide samples. For sFGFR3_Del4-C253S, two buffers (20 mM phosphate, 40 mM NaCl, pH 7.5, and 40 mM citrate, 40 mM NaCl, pH 6.5) were added to polypeptide samples. The melting temperature (T.sub.m) for sFGFR3_Del4-C253S in the 20 mM phosphate, 40 mM NaCl, pH 7.5 buffer was 52° C. and 56° C., and the T.sub.m for sFGFR3_Del4-C253S in the 40 mM citrate, 40 mM NaCl, pH 6.5 buffer was 55° C. and 60° C. (
(120) The ex vivo plasma stability of sFGFR3_Del4-D3 with a Histidine tag was determined by labeling purified sFGFR3_Del4-D3 with .sup.125I-tracer using the Bolton-Hunter method, followed by purification on PD-10 (Sephadex® G-25) columns. The trichloroacetic acid (TCA) precipitability of peak fractions was also determined to confirm stability of the .sup.125I-tracer. Mouse plasma (n=4) pre-warmed to 37° C. was spiked with the .sup.125I-sFGFR3_Del4-D3 to a concentration of ˜10 cpm/mL and then vortexed. The plasma samples were incubated with the .sup.125I-sFGFR3_Del4-D3 in an Eppendorf ThermoMixer® under gentle rotation (300 rpm). Aliquots were then collected for TCA precipitation (10 μl sample and 100 μl 2% BSA) and for injection onto an Fast Performance Liquid Chromatography (FPLC) column (20 μl sample and 150 μl 10 mM PBS, pH 7.4) at intervals of 0, 30, 60, 120, 180, and 360 minutes. Aliquots were stored on ice until TCA precipitation or FPLC injection was performed.
(121) For TCA precipitation, 1 mL ice cold 10% TCA was added to plasma samples, incubated for 10 minutes on ice, centrifuged at 4,000 g for 5 minutes, and then the supernatant and pellet were separated and both were counted in a gamma counter. For evaluation of the ex vivo plasma stability, 100 μl of the sample was injected on an FPLC column (Superdex® 200 10/300 GL) and eluted at a rate of 0.75 ml/min for 1.5 column volumes. Fractions of 1 ml were collected from the column and then measured in a gamma counter. The plasma stability of sFGFR3_Del4-D3 at 37° C. was determined to be 95% at 0 minutes, 95% at 2 hours, and ˜92% at 24 hours with only minor aggregation (
(122) The in vivo stability of sFGFR3_Del4-D3 in plasma after administration by intravenous and subcutaneous injection was also determined. sFGFR3_Del4-D3 was labeled with .sup.125I-tracer using the Bolton-Hunter method, followed by purification on PD-10 (Sephadex® G-25) columns. The .sup.125I-labeled sFGFR3_Del4-D3 (10 μCi in ˜50 μL PBS) was administered by intravenous or subcutaneous injection into anesthetized C57BI/6 mice. The .sup.125I-tracer protein dose (approximately 0.1 mg/kg) was complemented with unlabeled protein to a total dose of 2.5 mg/kg. Rat serum albumin used as a vascular marker was labeled with [.sup.3H]-NSP (N-succininidyl[2,3-.sup.3H]Propionate; Perkin Elmer) and purified on PD-10 (Sephadex® G25) columns.
(123) For the stability of sFGFR3_Del4-D3 in plasma after intravenous bolus injection, FPLC elution profiles showed no degradation products in plasma up to 15 minutes (
Example 16: Ligand Binding Activity of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S
(124) Experiments were performed to characterize the binding affinity of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S for human FGF2. The dissociation constant (Kd) of sFGFR3_Del4-D3 and Kd of sFGFR3_Del4-C253S for FGF2 were determined as described in Example 3 with a regeneration buffer of 20 mM phosphate, 40 mM NaCl, pH 7.5. Concentrations of 13 nM, 6.5 nM, 3.25 nM, and 1.75 nM were tested for both sFGFR3_Del4-D3 and sFGFR3_Del4-C253S. The Kd of sFGFR3_Del4-D3 was determined to be ˜3.6 nm, and the Kd of sFGFR3_Del4-C253S was determined to be ˜6.9 nm. These results indicate that sFGFR3_Del4-D3 and sFGFR3_Del4-C253S have binding activity for FGF2 in the low nM range.
Example 17: sFGFR3_Del4-D3 and sFGFR3_Del4-C253S Exhibit Functional Activity In Vitro
(125) Functional activity of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S was tested using a proliferation assay. Proliferation assays using ATDC5 cells genetically modified to overexpress the FGFR3.sup.ach mutation (ATDC5 FGFR3.sup.G380R cell lines) were performed as described in Example 4 with concentrations of 1 ug/ml, 10 ug/ml, and 50 ug/ml for sFGFR3_Del4-D3 and sFGFR3_Del4-C253S. At each of these concentrations, sFGFR3_Del4-C253S and sFGFR3_Del4-D3 restored proliferation of the FGFR3.sup.G380R cells (
Example 18: Pharmacokinetic Profile of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S
(126) The pharmacokinetic (PK) profile of sFGFR3_Del4-D3 administered subcutaneously or intravenously at a dose of 2.5 mg/kg was used to determine the terminal elimination half-life of sFGFR3_Del4-D3 (
Example 19: The Kidney and Liver are the Main Clearance Routes of sFGFR3_Del4-D3
(127) Clearance of sFGFR3_Del4-D3 was evaluated in kidney, liver, spleen, lung, and heart tissue after 30 minutes, 120 minutes, and 1440 minutes following intravenous administration of 2.5 mg/kg sFGFR3_Del4-D3 and after 30 minutes, 120 minutes, 240 minutes, 480 minutes, and 1440 minutes following subcutaneous administration of 2.5 mg/kg sFGFR3_Del4-D3. The liver and kidney were the major route of sFGFR3_Del4-D3 clearance for intravenous administration (
Example 20: sFGFR3_Del4-D3 does not Cross the Blood Brain Barrier
(128) Pharmacokinetic studies were also performed to determine the uptake of sFGFR3_Del4-D3 across the blood brain barrier in wild-type mice. After intravenous bolus injection, brain tissue uptake of sFGFR3_Del4-D3 was measured at three time points (30 minutes, 2 hours, and 24 hours). sFGFR3_Del4-D3 was injected as radiolabeled tracer (.sup.125I-sFGFR3_Del4-D3) with 2.5 mg/kg unlabeled sFGFR3_Del4-D3. The injected dose of .sup.125I-sFGFR3_Del4-D3 was about 10 μCi per animal, which corresponds to less than 0.1 mg/kg. After euthanizing the mice at 30 minutes, 2 hours, and 24 hours, the concentration of .sup.125I-sFGFR3_Del4-D3 in organs and plasma was measured by liquid scintillation counting.
(129) The .sup.125I-sFGFR3_Del4-D3 concentration was corrected for metabolism in plasma and in brain samples by measuring the fraction of trichloroacetic acid (TCA) precipitable material (e.g., intact tracer). The validity of the TCA correction was also confirmed by injecting samples on a size exclusion fast protein liquid chromatography (FPLC) column. The organ concentration of .sup.125I-sFGFR3_Del4-D3 was corrected for intravascular content (V.sub.0) by injecting radiolabeled albumin (.sup.3H-RSA) shortly before sacrificing the animal. The apparent organ volume of distribution of RSA represents V.sub.0. The dose of albumin was negligible (on the order of 1% of the physiological concentration). For all organs other than the brain, the concentrations were calculated by subtracting the vascular content and taking into account the TCA precipitable fraction in plasma. However, no correction was made for the uptake of degraded material into these organs other than the brain because no TCA precipitation was performed.
(130) The brain concentrations were calculated by the following formula: C.sub.brain(corr.)=[V.sub.d(sFGFR3_Del4-D3)−V.sub.0]×C.sub.plasma (terminal), in which V.sub.d(sFGFR3_Del4-D3) is the volume of distribution of sFGFR3_Del4-D3 in brain (calculated as C.sub.brain/C.sub.plasma), V.sub.0 is the volume of albumin distributed in the brain, and C.sub.plasma(terminal) is the plasma concentration of sFGFR3_Del4-D3 at the terminal sampling time. All concentrations were expressed as the percent of injected dose per gram or ml (% ID/g or % ID/mL), respectively, and the dose of the intravenous bolus equals 100%. These values can be converted to [mg/g] or [mg/mL] by multiplication with the injected dose: (body weight in g/1000 g)×2.5 mg. All body weights were in the range of 25 g-30 g.
(131) There was no detectable brain uptake of .sup.125I-sFGFR3_Del4-D3, as indicated by corrected brain concentrations (after correction for vascular content and degradation (TCA precipitability)) at at any of the measured time points (
Example 21: In Vivo Efficacy of sFGFR3_Del4-D3 for the Treatment of Achondroplasia
(132) sFGFR3_Del4-D3 and sFGFR3_Del4-C253S were each evaluated at a subcutaneous dose of 2.5 mg/kg once or twice weekly or 10 mg/kg twice weekly. Breeding was performed to generate 30 litters with half wild type and half heterozygous Fgfr3.sup.ach/+ mice (Table 4).
(133) TABLE-US-00004 TABLE 4 Subcutaneous administration of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S to wild type (WT) and Fgfr3.sup.ach/+ mice. PBS 2.5 mg 2.5 mg 10 mg (pooled) 1 × week 2 × week 2 × week sFGFR3_Del4- WT 65 26 22 23 D3 Fgfr3.sup.ach/+ 43 26 25 30 total N = 260 sFGFR3_Del4- WT 65 26 22 23 C253S Fgfr3.sup.ach/+ 27 22 18 28 total N = 231 % 62.8 84.6 72.0 93.3 survival % 37.2 15.4 28.0 6.7 mortality
(134) At day 3, all newborn mice from a single litter received the same dose. Control litters received 10 μl of PBS (vehicle). Thereafter, subcutaneous injections of sFGFR3_Del4-D3 and sFGFR3_Del4-C253S were administered at doses of 2.5 mg/kg once or twice weekly or 10 mg/kg twice a week for three weeks, alternatively on the left and right sides of the back. Mice were observed daily with particular attention to locomotion and urination alterations and weighed on days of injection. Mice with complications were observed twice a day for surveillance. Previous data indicated there was no statistical difference between males and females, and thus, males and females were considered one group for all analyses.
(135) At day 22, all animals were sacrificed by lethal injection of pentobarbital, and gender was determined. All subsequent measurements and analyses were performed without knowledge of mice genotype to avoid investigator bias. Genotyping was performed at the end of the study to reveal the correspondence of data with a specific genotype. Since achondroplasia is a disease with phenotypic variability, all animals were included in the study. Animals dead before day 22 were used to investigate the impact of treatment on premature death. Surviving animals at day 22 were used for all analyses. All experiments and data measurements were performed by blinded experimenters at all time points.
(136) Subcutaneous administration of sFGFR3_Del4-D3 at 2.5 mg/kg once or twice weekly or 10 mg/kg twice weekly increased survival of Fgfr3.sup.ach/+ mice relative to Fgfr3.sup.ach/+ mice receiving PBS (
(137) TABLE-US-00005 TABLE 5 P-values for subcutaneous administration of sFGFR3_Del4-D3 to wild type (WT) and Fgfr3.sup.ach/+ mice. Group Comparison P Value Wt vs ach *** Fgfr3.sup.ach/+ PBS vs Fgfr3.sup.ach/+ 2.5 mg/kg, 1× *** Fgfr3.sup.ach/+ PBS vs Fgfr3.sup.ach/+ 2.5 mg/kg, 2× * Fgfr3.sup.ach/+ PBS vs Fgfr3.sup.ach/+ 10 mg/kg, 2× *** Wt PBS vs Fgfr3.sup.ach/+ 10 mg/kg, 2× ns
(138) Subcutaneous administration of sFGFR3_Del4-D3 at 2.5 mg/kg once or twice weekly or 10 mg/kg twice weekly also decreased the severity and frequency of locomotor problems and complications in abdominal breathing in Fgfr3.sup.ach/+ mice relative to Fgfr3.sup.ach/+ mice receiving PBS (
(139) Subcutaneous administration of sFGFR3_Del4-D3 also significantly increased total body length, including axial length and tail length, and long bones (p=0.07) in Fgfr3.sup.ach/+ mice receiving 2.5 mg/kg sFGFR3_Del4-D3 once or twice weekly or 10 mg/kg sFGFR3_Del4-D3 twice weekly relative to Fgfr3.sup.ach/+ mice receiving PBS (
(140) Subcutaneous administration of sFGFR3_Del4-D3 also resulted in a dose-dependent improvement in cranial ratio (length/width (L/VV)) in Fgfr3.sup.ach/+ mice relative to Fgfr3.sup.ach/+ mice receiving PBS (
(141) TABLE-US-00006 TABLE 6 Bone measurements (presented in mm and mean ± SEM) for body length, tail, femur, tibia, and cranial ratio of WT and Fgfr3.sup.ach/+ mice administered subcutaneously sFGFR3_Del4-D3. Efficacy of sFGFR3_Del4-D3 PBS in Fgfr3.sup.ach/+ 2.5 mg/kg 2.5 mg/kg 10 mg/kg WT mice once weekly twice weekly twice weekly Body length 144.8 ± 0.53 129.2 ± 1.98 135 ± 1.48 135.5 ± 1.75 135.2 ± 1.58 Tail 77.65 ± 0.39 70.25 ± 1.1 73.37 ± 1.66 73.69 ± 1.5 74.95 ± 0.91 Femur 10.94 ± 0.05 10.14 ± 0.13 10.47 ± 0.08 10.58 ± 0.09 10.63 ± 0.10 Tibia 14.19 ± 0.05 13.67 ± 0.14 14.02 ± 0.10 14.09 ± 0.12 14.25 ± 0.12 Cranial ratio 1.99 ± 0.01 1.79 ± 0.01 1.83 ± 0.02 1.85 ± 0.01 1.86 ± 0.02
(142) Additionally, comparison of the bone measurements for Fgfr3.sup.ach/+ mice administered sFGFR3 Del1 at a dosage of 2.5 mg/kg twice weekly show that administration sFGFR3_Del4-D3 at a dosage of 2.5 mg/kg twice weekly was comparable to or more effective in increasing the bone, tail, femur, and tibia length and improving the cranial ratio of Fgfr3.sup.ach/+ mice (Table 7). In particular, the body length of Fgfr3.sup.ach/+ mice administered sFGFR3_Del4-D3 improved to 135.5±1.75 mm relative to 134.4±1.17 mm for Fgfr3.sup.ach/+ mice administered sFGFR3_Del1; the tail length of Fgfr3.sup.ach/+ mice administered sFGFR3_Del4-D3 improved to 73.69±1.5 mm relative to 71.58±0.86 mm for Fgfr3.sup.ach/+ mice administered sFGFR3_Del1; the femur length of Fgfr3.sup.ach/+ mice administered sFGFR3_Del4-D3 improved to 10.58±0.09 mm relative to 10.01±0.06 mm for Fgfr3.sup.ach/+ mice administered sFGFR3_Del1; the tibia length of Fgfr3.sup.ach/+ mice administered sFGFR3_Del4-D3 improved to 14.09±0.12 mm relative to 13.27±0.31 mm for Fgfr3.sup.ach/+ mice administered sFGFR3_Del1; and the cranial ratio of Fgfr3.sup.ach/+ mice administered sFGFR3_Del4-D3 improved to 1.85±0.01 mm relative to 1.81±0.02 mm for Fgfr3.sup.ach/+ mice administered sFGFR3 Del1.
(143) TABLE-US-00007 TABLE 7 Bone measurements (presented in mm and mean ± SEM) for body length, tail, femur, tibia, and cranial ratio of WT and Fgfr3.sup.ach/+ mice administered subcutaneously sFGFR3_Del1 (data described in Garcia et al. Sci. Transl. Med. 5:203ra124, 2013). Efficacy of sFGFR3_Del1 PBS in Fgfr3.sup.ach/+ 0.25 mg/kg 2.5 mg/kg WT mice twice weekly twice weekly body length 133.9 ± 0.8 118.5 ± 1.76 132.4 ± 1.26 134.4 ± 1.17 tail 71.9 ± 0.49 64.48 ± 1.1 71.05 ± 0.99 71.58 ± 0.86 femur 10.05 ± 0.17 9.67 ± 0.16 9.85 ± 0.10 10.01 ± 0.06 tibia 13.43 ± 0.19 12.62 ± 0.18 12.87 ± 0.14 13.27 ± 0.31 cranial ratio 1.94 ± 0.01 1.75 ± 0.01 1.77 ± 0.02 1.81 ± 0.02
Example 22: No Organ Toxicity Associated with Administration of sFGFR3_Del4-D3
(144) Histopathological studies were performed to characterize organ toxicity associated with sFGFR3_Del4-D3 administration. Wild type mice (6 males and 6 females per dose) were administered PBS, 2.5 mg/kg sFGFR3_Del4-D3 once weekly, 2.5 mg/kg sFGFR3_Del4-D3 twice weekly, or 10 mg/kg sFGFR3_Del4-D3 twice weekly. Organs investigated included the kidney, skin, salivary glands, mandibular lymph nodes, gall bladder, spleen, pancreas, lungs, heart, aorta, jejunum, colon, and liver. There were no histopathological results indicating organ toxicity in wild-type mice administered any of the doses of sFGFR3_Del4-D3. These results indicate that there was no toxicity associated with administration of sFGFR3_Del4-D3 up 10 mg/kg twice weekly.
Example 23: Determination of Binding Affinity of sFGFR3_Del4-D3 to Fibroblast Growth Factors
(145) We determined that sFGFR3_Del4-D3 binds to Fibroblast Growth Factors (FGF) ligands and acts as a decoy to prevent the binding of FGFs to the membrane bound FGFR3. Surface Plasmon Resonance was performed using a BIACORE™ T200 (GE Healthcare) to determine the K.sub.d values for different human FGFs (hFGFs) binding to immobilized sFGFR3_Del4-D3. In particular, K.sub.d values for the paracrine hFGFs of hFGF1 (
(146) TABLE-US-00008 TABLE 8 Summary of K.sub.d determination and values for human, paracrine FGFs (hFGF1, hFGF2, hFGF9, and hFGF18) and human, endocrine FGFs (hFGF19 and hFGF21). Chi.sup.2 K.sub.D (M) Chi.sup.2 Paracrine k.sub.a1 k.sub.a2 K.sub.D (M) (RU.sup.2) Steady (RU.sup.2) FGFs Binding (1/Ms) (1/Ms) k.sub.d1 (1/s) k.sub.d2 (1/s) Kinetic average state average FGF1 2:1 2.0* 10.sup.+11 1.2* 10.sup.−3 1610 6.4 * 10.sup.−4 2.6* 10.sup.−9 0.138 5.7* 10.sup.−9 0.247 binding (+/− 1.9*10.sup.−9, (+/− 2.1 *10.sup.−9, & n = 3) n = 3) steady state FGF2 1:1 9.0* 10.sup.+5 4.75* 10.sup.−4 6.1* 10.sup.−10 13.6 binding (+/− 1.7*10.sup.−10, n = 3) FGF9 2:1 2.3* 10.sup.+6 3.0* 10.sup.−2 2.6* 10.sup.−2 3.6* 10.sup.−3 1.8* 10.sup.−9 0.14 3.6* 10.sup.−9 0.25 binding (+/− (n = 1) & 0.25*10.sup.−9, steady n = 3) state FGF18 1:1 2.0* 10.sup.+5 9.1* 10.sup.−3 4.5* 10.sup.−9 9.7 6.4*10.sup.−9 11.8 binding (+/− 2.5*10.sup.−9, (+/− & n = 3) 0.89*10.sup.−9, steady n = 4) state Endocrine FGFs FGF19 2:1 5.4* 10.sup.+4 7.3* 10.sup.−3 1.5* 10.sup.−1 3.6* 10.sup.−3 4.8* 10.sup.−7 0.05 binding (+/− 3.2*10.sup.−7, n = 3) FGF21 2:1 258 1.8* 10.sup.−2 5.5* 10.sup.−3 1.4* 10.sup.−3 2.8* 10.sup.−5 0.56 binding (n = 2)
(147) For FGF2 and FGF18, a good fit was achieved with a 1:1 binding model, which is the most direct model of binding affinity. This model describes a 1:1 binding interaction at the surface of the chip with immobilized SFGFR3_DEL4-D3 binding different FGFs: A+B=AB with single on- and off rate. The 2:1 model also describes a 1:1 interaction of FGF binding to SFGFR3_DEL4-D3, but also assumes a conformational change that stabilizes the complex: A+B=AB=AB* and represents two on- and off-rates. This model assumes that the conformationally changed complex (SFGFR3_DEL4-D3 bound to FGF) can only dissociate by reversing the conformational change. The experimental data for hFGF1, hFGF9, hFGF19, and hFGF21 were determined to fit the 2:1 model very well, and thus, K.sub.d for hFGF1, hFGF9, hFGF19, and hFGF21 were derived from the 2:1 model.
(148) Despite hFGF1, hFGF9, hFGF19, and hFGF21 all having a K.sub.d in the low nM range, the kinetic profiles of these hFGFs differed significantly. For example, FGF1 binds sFGFR3_Del4-D3 with a very fast on-rate and off-rate, while FGF2 does not bind sFGFR3_Del4-D3 with as fast of an on-rate or off-rate as FGF1, resulting in an overall smaller K.sub.d for FGF2 compared to FGF1 (Table 8). A significantly lower affinity was measured between sFGFR3_Del4-D3 and hFGF19 or hFGF21, which are members of the endocrine FGF15/FGF19 subfamily, relative to the paracrine hFGFs (Table 8 and
(149) These results demonstrate that there was a high affinity interaction of sFGFR3_Del4-D3 with hFGF1, hFGF2, hFGF9, and hFGF18, while there was a low affinity interaction of sFGFR3_Del4-D3 with FGF19 and FGF21. The low affinity of sFGFR3_Del4-D3 for FGF19 and FGF21 is advantageous as sFGFR3_Del4-D3 will have a low probability of interfering with the function of these FGFs in vivo.
Example 24: In Vitro Proliferation Assay of sFGFR3_Del4-D3
(150) Following binding of FGFs, FGFR3 dimerizes to initiate signaling cascades. Several downstream signaling pathways are associated with FGF signaling. In chondrocytes, dimerized FGFR3 results in an anti-proliferative signal/early differentiation signal into the chondrocyte, which eventually leads to inhibition of bone growth. For example, the RAS/MAPK pathway propagates signals to negatively affect proliferation, terminal differentiation, and post-mitotic matrix synthesis, and the STAT1 pathway mediates the inhibition of chondrocyte proliferation in concert with the cell cycle regulators p107 and 130 and cell cycle inhibitor p21Waf/Cip1. Gene expression studies suggest a number of other pathways are also involved in down-regulation of growth-promoting molecules or induction of anti-proliferative functions.
(151) To study FGFR3-decoy induced inhibition of FGFR3.sup.G380R in a chondrocytic cell model, studies were performed to determine the effect of sFGFR3_Del4-D3 on the proliferation of ATDC5 cells genetically modified to overexpress the FGFR3.sup.ach mutation (ATDC5 FGFR3.sup.G380R cells). The chondrocytic cell line ATDC5 cell, which was first isolated from the differentiating teratocarcinoma stem cell line AT805, is commonly used as a model for in vitro chondrocyte research. ATDC5 cells were first infected with a retroviral expression vector and a stable cell line expressing FGFR3.sup.G380R was generated. The expression of FGFR3.sup.G380R in the ATDC5 cell line was determined via Western blot (
OTHER EMBODIMENTS
(152) All publications, patents, and patent applications mentioned in the above specification are hereby incorporated by reference to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. Various modifications and variations of the described methods, pharmaceutical compositions, and kits of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific embodiments, it will be understood that it is capable of further modifications and that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention that are obvious to those skilled in the art are intended to be within the scope of the invention. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure come within known customary practice within the art to which the invention pertains and may be applied to the essential features herein before set forth.