The present invention relates to novel human CD3 antigen-binding polypeptides and their preparation and use in the treatment and/or diagnosis of various diseases, and also relates to bispecific antibody molecules capable of activating immune effector cells and their use in diagnosis and/or treatment of various diseases.

It was discovered that the use of an antigen-binding molecule having a cancer-specific antigen-binding domain, and a TNF superfamily-binding domain or a TNF receptor superfamily-binding domain enables agonist activity against a factor belonging to the TNF superfamily or the TNF receptor superfamily to be exhibited only in the presence of cancer-specific antigen-expressing cells, thus leading to activation of immune cells and thereby maintain anti-tumor activity while avoiding side effects such as hepatotoxicity. It was also discovered that concomitant use of the antigen-binding molecule with an antigen-binding molecule having a cancer-specific antigen-binding domain and a T cell receptor complex-binding domain can avoid side effects while increasing the anti-tumor activity.

An antibody or antigen-binding portion thereof which binds to PSMA and comprises a heavy chain variable domain comprising the sequence given in SEQ ID NO:33, wherein SEQ ID NO:33 is: EVQLVQSGX.sup.9E X.sup.11KKPGASVKV SCKX.sup.24SGYTFT EYTIHWVX.sup.38QA X.sup.41 GKGLEWIGN INPNX.sup.55GGTTY NOKFEDRX.sup.68TX.sup.70 TVDKSTSTAY MELSSLRSED TAVYYCAAGW NFDYWGOGTT VTVSS wherein: X.sup.9 is A or P X.sup.11 is V or L X.sup.24 is A or T X.sup.38 is R or K X.sup.41 is P or H X.sup.55 is N or Q X.sup.68 is V or A; and X.sup.70 is I or L whereby the heavy chain variable domain comprises up to 3 amino acid sequence modification(s) between positions 1-30, 36-49, 67-98 and 105-115 of SEQ ID NO: 33. The invention also provides compounds that include the antibody or antigen-binding portion thereof, such as conjugates, and their use in the treatment or diagnosis of diseases, in particular cancers, particularly prostate cancer.

Mucin 16 (MUC16) is highly expressed in ovarian cancer and expression on cancer cells is shown to protect tumor cells from the immune system. The present invention provides novel full-length human IgG antibodies that bind to human and MUC16 (monospecific antibodies). The present invention also provides novel bispecific antibodies (bsAbs) that bind to both MUC16 and CD3 and activate T cells via the CD3 complex in the presence of MUC16-expressing tumors. According to certain embodiments, the present invention provides bispecific antigen-binding molecules comprising a first antigen-binding domain that specifically binds human and monkey CD3, and a second antigen-binding molecule that specifically binds human and monkey MUC16. In certain embodiments, the bispecific antigen-binding molecules of the present invention are capable of inhibiting the growth of tumors expressing MUC16. The bispecific antigen-binding molecules of the invention are useful for the treatment of diseases and disorders in which an upregulated or induced MUC16-targeted immune response is desired and/or therapeutically beneficial. For example, the bispecific antibodies of the invention are useful for the treatment of various cancers, including ovarian cancer. The present invention also includes anti-MUC16 antibody drug conjugates which inhibit tumor growth in vivo. In some embodiments, the anti-MUC16 antibodies are useful in diagnostic methods for identifying the presence of MUC16 in tissue and/or plasma samples.

Provided herein are trispecific and/or trivalent binding proteins comprising four polypeptide chains that form three antigen binding sites that specifically bind one or more target proteins, wherein a first pair of polypeptides forming the binding protein possess dual variable domains having a cross-over orientation, and wherein and a second pair of polypeptides possess a single variable domain forming a single antigen binding site. In some embodiments, the binding proteins comprise a binding site that binds a CD28 polypeptide, a binding site that binds a CD3 polypeptide, and a binding site that binds a third polypeptide, such as a tumor target protein. In some embodiments, the binding proteins comprise four polypeptide chains that form three antigen binding sites that specifically bind one or more HIV target proteins. The disclosure also relates to methods for making trispecific and/or trivalent binding proteins and uses of such binding proteins.

Provided are an anti-CD47/anti-PD-L1 antibody, a pharmaceutical composition of the anti-CD47/anti-PD-L1 antibody, and applications thereof. The anti-CD47/anti-PD-L1 antibody provides antitumor activity, is free of significant red blood cell toxicity, and is applicable in preparing an antitumor medicament.

The present invention concerns antigen binding proteins directed against PRAME protein-derived antigens. The invention in particular provides antigen binding proteins which are specific for the tumor expressed antigen PRAME, wherein the tumor antigen comprises or consists of SEQ ID NO: 50 and is in a complex with a major histocompatibility complex (MHC) protein. The antigen binding proteins of the invention contain, in particular, the complementary determining regions (CDRs) of novel engineered T cell receptors (TCRs) that specifically bind to said PRAME peptide. The antigen binding proteins of the invention are for use in the diagnosis, treatment and prevention of PRAME expressing cancerous diseases. Further provided are nucleic acids encoding the antigen binding proteins of the invention, vectors comprising said nucleic acids, recombinant cells expressing the antigen binding proteins and pharmaceutical compositions comprising the antigen binding proteins of the invention.

Provided herein are heterodimeric bispecific antibodies that can mediate cytolysis of a target cell by an immune effector cell, nucleic acids encoding such antibodies, methods of making such antibodies, and methods of using such antibodies. These antibodies comprise two different polypeptide chains, each comprising two immunoglobulin variable regions and, optionally, a half life-extending moiety.

The present invention relates to a bispecific antibody, which is a tetravalent symmetrical bispecific antibody with a structure of F(ab).sub.2-(Fv).sub.2-Fc and comprises two identical fusion heavy chains and two identical fusion light chains.

The present application provides a recombinant fusion protein containing an anti-PD-L1 antibody or an antibody fragment thereof, with each paratope of the anti-PD-L1 antibody or antibody fragment thereof linked via a linker to an extracellular Ig-like domain of a signal-regulatory protein (SIRP) at N-terminus of a heavy chain variable region or a light chain variable region constituting the paratope, wherein the recombinant fusion protein can bind to CD47, PD-L1 and FcR simultaneously. The present application also provides a nucleic acid molecule encoding the recombinant fusion protein, an expression vector containing the nucleic acid molecule, a method for producing the recombinant fusion protein and a method for treating a disease associated with over-expression of CD47 and/or PD-L1 using the recombinant fusion protein.