Combination therapy for ovarian cancer

Abstract

The present invention provides a method of treating ovarian cancer in a mammal in need of such treatment comprising administering an effective amount of a combination of gemcitabine, cisplatin or carboplatin, and 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine.

Claims

1. A method of treating ovarian cancer in a mammal comprising administering to said mammal a combination of gemcitabine, a platinum agent selected from the group consisting of cisplatin and carboplatin, and 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine or a pharmaceutically acceptable salt thereof.

2. The method of claim 1 wherein gemcitabine and the platinum agent are administered up to 2 days after 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine or a pharmaceutically acceptable salt thereof is administered and gemcitabine is administered again up to 7 days later.

3. The method according to claim 1 wherein the administration is during a 21-day treatment cycle.

4. The method according to claim 1 wherein the pharmaceutically acceptable salt is dimethanesulfonate salt.

5. The method according to claim 2 wherein the administration is during a 21-day treatment cycle.

6. The method according to claim 2 wherein the pharmaceutically acceptable salt is dimethanesulfonate salt.

7. The method according to claim 2 wherein the 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H -imidazol-4-yl]-3-(2,2-dimethylpropyl)-3H-imidazo[4,5-b]pyridine-2-ylamine or the salt thereof is administered at 200 mg or 300 mg.

8. The method according to claim 7 wherein gemcitabine is administered at 1000 mg/m.sup.2 intravenously over 30 minutes on days 3 and 10 and the platinum agent is carboplatin AUC 4 and is administered intravenously over 30 minutes on day 3.

9. The method according to claim 2 wherein the 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H -imidazol-4-yl]-3-(2,2-dimethylpropyl)-3H-imidazo[4,5-b]pyridine-2-ylamine or the salt thereof is administered at 200 mg every 12 hours on days 1-10 of a 21-day treatment cycle.

10. The method according to claim 9 wherein gemcitabine is administered at 100 mg/m.sup.2 intravenously over 30 minutes on days 3 and 10 and the platinum agent is carboplatin AUC 4 and is administered intravenously over 30 minutes on day 3.

Description

REFERENCE EXAMPLE 1

5-[2-tert-Butyl-5-(4-fluorophenyl)-1H-imidazol-4-yl]-3-(2,2-dimethylpropyl)imidazo[4,5-b]pyridin-2-amine dimethanesulfonate or 5-[2-tert-Butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine dimethansulfonate

(1) ##STR00006##

(2) 1-[2-Amino-3-(2,2-dimethylpropyl)imidazo[4,5-b]pyridin-5-yl]-2-(4-fluorophenyl)ethane-1,2-dione (354 g, 1 mol) is mixed with ethanol (2.8 L), ammonium acetate (550.0 g, 7.1 mol), and trimethyl acetaldehyde (110 g, 1.3 mol). The reaction is heated at about 70° C. (the reaction temperature is kept below refluxing to help suppress the sublimation of NH.sub.4OAc) until the disappearance of the dione as monitored by HPLC or LC-MS. After the completion of the reaction (usually overnight), the mixture is concentrated under vacuum. Ethyl acetate (5.3 L) and water (3.5 L) are added, followed by 1 N NaOH (1.4 L). The mixture is stirred for 20-30 minutes at room temperature. The phases are separated and the aqueous phase is extracted with ethyl acetate (2.8 L). The combined ethyl acetate portions are washed twice with 10 volumes of brine. The ethyl acetate solution is evaporated to about 1.2 L (about 3 volumes). Ethanol (2.8 L) is added and the mixture heated to about 65° C. Methanesulfonic acid (240.0 g, 2.5 mol) in ethyl acetate (600 mL) is added in a fast dropwise fashion. The mixture is maintained at about 65° C. for 3 hours. The heat source is removed and the reaction is cooled to room temperature with stirring for 2 hours more. The solid product is collected by filtration, rinsed with ethyl acetate (500 mL), and dried in a vacuum oven at about 45° C. to obtain the title compound (490 g, 80%). ES/MS m/z 421.5 (M+1). .sup.1H NMR (300 MHz, DMSO-d.sub.6): δ 8.99 (s, 2H), 7.90 (d, 1H, J=9.0 Hz); 7.86 (d, 1H, J=9.0 Hz); 7.60 (dd, 2H, J=9.0 Hz), 7.34 (dd, 2H, J=9.0 Hz); 3.68 (s, 2H); 2.35 (s, 6H); 1.51 (s, 9H); 0.71 (s, 9H).

(3) The following Examples illustrate improved efficacy of the triple combination administration of the compounds, 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine (dimethanesulfonate salt (Compound A)), gemcitabine, and a platinum agent over the dual combination of gemcitabine and a platinum agent in mouse xenograft studies of human ovarian cancer. It should be understood that the Examples are set forth by way of illustration and not limitation, and that various modifications may be made by one of ordinary skill in the art.

EXAMPLE 1

In Vivo Triple Combination with Compound a, Gemcitabine, and Cisplatin

(4) The purpose of this study is to compare the dual combination treatment of gemcitabine and cisplatin and the triple combination treatment (including Compound A) in a xenograft mouse model of human ovarian cancer to determine which is more efficacious.

(5) Human tumor mouse xenografts are generated from early passages of the following ovarian cancer cell lines: A-2780 (National Cancer Institute), SK-OV-3x.luc (SK-OV-3 cell line modified to express luciferase (#1, medium expressing), Indiana University). A-2780 ovarian cancer cells are grown in RPMI 1640 with L-glutamine, 25 mM HEPES (Invitrogen 22400-089) supplemented with 1 mM pyruvate and 10% Certified Fetal Bovine Serum (Gibco 16000, FBS). SK-OV-3x.luc cells (ovarian cancer cells) are grown in McCoy's 5A Medium with L-glutamine (Invitrogen 16600-082) supplemented with non-essential amino acids, 1 mM pyruvate and 10% FBS.

(6) Harlan athymic nude mice (6-7 weeks old) are housed with ad libitum feed and water, and are acclimated for one week prior to subcutaneous xenograft implantation in the right rear flank with a defined number of cells. A-2780 or SK-OV-3x.luc implants consist of 0.1 mL of cells (2 or 5×10.sup.6 cells, respectively) in serum-free media with 0.1 mL MATRIGEL® (BD Biosciences) for a final volume of 0.2 mL. Tumors are allowed to develop to a volume of 120-150 mm.sup.3 and are then randomized into treatment groups to attain a consistent average tumor size across all groups. Each treatment group of the SK-OV-3x.luc study is 12 animals; each group of the A-2780 study is 20 animals.

(7) Compound A is prepared weekly in hydroxyethylcellulose (HEC) 1%/TWEEN® 80 0.25%/Antifoam 0.05% (HEC/TWEEN®) and stored at 4° C. A dose of 30 mg/kg Compound A for the SK-OV-3x.luc treatment group (or 10 mg/kg for the A-2780 treatment group), or its vehicle, is administered orally by gastric gavage three times daily (TID) in a volume of 0.2 mL for 3 weeks. The treatment protocol includes a two day initial treatment with Compound A prior to introduction of the gemcitabine and cisplatin treatments.

(8) Cisplatin and gemcitabine are diluted in PBS, prepared and administered weekly as 0.2 mL intraperitoneal injections. The volume is administered as a constant as illustrated in Table 1.

(9) TABLE-US-00001 TABLE 1 Gemcitabine 100 mg/kg  0.2 mL 50 mg/kg  0.2 mL 25 mg/kg  0.2 mL Cisplatin at: 4 mg/kg 0.2 mL 2 mg/kg 0.2 mL 1 mg/kg 0.2 mL

(10) Once weekly (QW) treatments of gemcitabine and cisplatin are given commencing on the third day at 0.5 and 1 hour, respectively, after the 7th dose (corresponding to just over two full days of Compound A dosing) of Compound A or vehicle each week. The highest doses of gemcitabine and cisplatin are selected based on efficacy as single agents, and fixed ratio dilutions of these are dosed in combination (sequential administration as separate compounds): 100 mg/kg gemcitabine+4 mg/kg cisplatin (100+4); 50 mg/kg gemcitabine+2 mg/kg cisplatin (50+2); or 25 mg/kg gemcitabine+1 mg/kg cisplatin (25+1). The SK-OV-3x.luc and A-2780 treatment groups are administered the triple combination therapy according to the following dosing regimens. Corresponding vehicles are employed where no treatment is indicated. 1. HEC/TWEEN®, 0.2 mL, oral, TID×21/PBS, 0.2 mL+0.2 mL, IP, QW×3 2. Compound A, 10 (or 30) mg/kg, oral, TID×21/PBS, 0.2+0.2 mL, IP, QW×3 3. HEC/TWEEN®, 0.2 mL, oral, TID×21/gemcitabine+cisplatin (25+1) mg/kg, IP, QW×3 4. HEC/TWEEN®, 0.2 mL, oral, TID×21/gemcitabine+cisplatin (50+2) mg/kg, IP, QW×3 5. HEC/TWEEN®, 0.2 mL, oral, TID×21/gemcitabine+cisplatin (100+4) mg/kg, IP, QW×3 6. Compound A, 10 (or 30) mg/kg, oral, TID×21/gemcitabine+cisplatin, 25+1 mg/kg, IP, QW×3 7. Compound A, 10 (or 30) mg/kg, oral, TID×21/gemcitabine+cisplatin, 50+2 mg/kg, IP, QW×3 8. Compound A, 30 mg/kg, oral, TID×21/gemcitabine+cisplatin, 100+4 mg/kg, IP, QW×3* *SK-OV-3x.luc study only

(11) Tumor volume and body weight are recorded and analyzed twice weekly using a data capture and analysis tool. Tumor volume (mm.sup.3) is estimated by using the formula: ν=l×w.sup.2×0.536 where l=larger of measured diameter and w=smaller of perpendicular diameter. Antitumor activity is calculated as a percent reduction of treated (T) tumor volume relative to untreated control (C) tumor volume [1−(T/C)]×100. Tumor volume data are transformed to a log scale to equalize variance across time and treatment groups. The log volume data are analyzed with a two-way repeated measures analysis of variance by time and treatment using the MIXED procedures in SAS software (version 8.2). The correlation model for the repeated measures is spatial power. Treated groups are compared to the control group at each time point. The MIXED procedure is also used separately for each treatment group to calculate adjusted mean and standard error at each time point. Both analyses account for the autocorrelation within each animal and the loss of data that occurs when animals with large tumors are removed from the study early. The adjusted mean and standard error are plotted for each treatment group versus time. By convention, p-values ≦0.05 indicate significant differences in tumor growth. Maximal percentage of weight loss and final tumor volume measurements are presented with the resultant statistical comparison of tumor growth inhibition between the individual and combination treatments.

(12) The final average tumor volume of SK-OV-3x.luc xenografts treated for 3 weeks with Compound A alone, or with lower dose combinations of gemcitabine and cisplatin (25+1, 50+2) administered on a once weekly schedule, is not significantly different from vehicle control (Table 2). The highest gemcitabine+cisplatin combination (100+4) yields tumor growth inhibition relative to vehicle control. The co-treatment of each of the gemcitabine+cisplatin treated animals with Compound A results in an enhancement of tumor growth inhibition. The combinations of 25+1, 50+2 and 100+4 with Compound A achieve or surpass the anti-tumor response to the 100+4 combination.

(13) The triple combination treatment of each of the 25+1 and 50+2 gemcitabine+cisplatin treated animals with Compound A results in an improvement of tumor growth inhibition over the dual combination of gemcitabine+cisplatin as shown in Table 2. Specifically, the combinations of 25+1, 50+2, and 100+4 with Compound A significantly surpass the anti-tumor response to their respective 25+1, 50+2, and 100+4 dual combination.

(14) TABLE-US-00002 TABLE 2 SK-OV-3x.luc tumor growth inhibition with gemcitabine, cisplatin and Compound A combination treatments Max % final tumor significance (p values) final wt. loss volume vehicle A (G + C).sup.1 n vehicle 0.0 505 ± 51 — — — 12 A 1.4 522 ± 54 NS — — 10  25 + 1 5.2 407 ± 39 NS NS — 12  50 + 2 4.1 524 ± 54 NS NS — 12 100 + 4 13.7 337 ± 43 0.010 0.007 — 11  25 + 1/A 5.4 253 ± 42 <0.001 <0.001 0.002 11  50 + 2/A 7.7 364 ± 30 0.030 0.021 0.017 10 100 + 4/A 13.1 202 ± 15 <0.001 <0.001 0.001 11 .sup.1Each gemcitabine + cisplatin (G + C)/A combination is compared to its matched combination (G + C) only.

(15) In a second model, A2780 ovarian tumor model, the triple combination treatment of each of the gemcitabine+cisplatin treated animals with Compound A results in an improvement of tumor growth inhibition over the dual combination of gemcitabine+cisplatin, as shown in Table 3. Specifically, the combinations of 25+1 and 50+2 with Compound A significantly surpass the anti-tumor response to the 25+1 and 50+2 dual combination.

(16) TABLE-US-00003 TABLE 3 A-2780 tumor growth inhibition with gemcitabine, cisplatin and Compound A combination treatments Max % final tumor significance (p values) final wt. loss volume vehicle A (G + C).sup.1 n vehicle 1.8 2257 ± 279 — — — 20 A 3.0 1828 ± 208 NS — — 20  25 + 1 4.6 536 ± 58 <0.001 <0.001 — 19  50 + 2 5.1 381 ± 39 <0.001 <0.001 — 19 100 + 4 7.4 219 ± 22 <0.001 <0.001 — 20  25 + 1/A 7.9 361 ± 34 <0.001 <0.001 0.009 19  50 + 2/A 8.6 218 ± 14 <0.001 <0.001 <0.001 20 .sup.1Each gemcitabine + cisplatin (G + C)/A combination is compared to its matched combination (G + C) only. (100 + 4) is not evaluated in combination with Compound A.

EXAMPLE 2

In vivo Triple Combination Therapy with Compound A, Gemcitabine, and Carboplatin

(17) Carboplatin (25 mg/kg-100 mg/kg) may be substituted for cisplatin essentially as described in Example 1.

(18) The compounds described in the present invention are preferably formulated as pharmaceutical compositions administered by a variety of routes. Most preferably, such compositions are for oral, intravenous, or intraperitoneal administration. Such pharmaceutical compositions and processes for preparing the same are well known in the art. See, e.g., REMINGTON: THE SCIENCE AND PRACTICE OF PHARMACY (D. Troy, et al., eds., 21.sup.st ed., Lippincott Williams & Wilkins, 2005).

(19) The compounds of the present invention are generally effective over a wide dosage range. The amount of 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine administered normally falls within the range of about 100-420 mg every 12 hours for 10 days, more preferably 100-300 mg every 12 hours for 10 days, and most preferably 200 mg every 12 hours for 10 days or alternatively 300 mg every 12 hours for 10 days. It is anticipated that 5-[2-tert-butyl-5-(4-fluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl- propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine will be administered for at least two days prior to the initiation of the gemcitabine and cisplatin or gemcitabine and carboplatin regimen.

(20) According to the FDA approved dosing regimen, the combination administration of gemcitabine and carboplatin should be administered intravenously at a dose of 1000 mg/m2 over 30 minutes on days 1 and 8 of each 21-day treatment cycle. Carboplatin AUC 4 should be administered intravenously on day 1 after gemcitabine administration. Patients should be monitored prior to each dose with a complete blood count, including differential counts. Patients should have an absolute granulocyte count >1500×106/L and a platelet count >100,000×106/L prior to each cycle.

(21) Dose Modifications

(22) Gemcitabine dosage adjustment for hematological toxicity within a cycle of treatment is based on the granulocyte and platelet counts taken on day 8 of therapy. If marrow suppression is detected, gemcitabine dosage should be modified according to guidelines in Table 4.

(23) TABLE-US-00004 TABLE 4 Day 8 Dosage Reduction Guidelines for Gemcitabine in Combination with Carboplatin Absolute granulocyte Platelet count % of full count (×10.sub.6/L) (×10.sub.6/L) dose ≧1500 and ≧100,000 100 1000-1499 and/or 75,000-99,999  50 <1000 and/or  <75,000 Hold

(24) In general, for severe (Grade 3 or 4) non-hematological toxicity, except nausea/vomiting, therapy with gemcitabine should be held or decreased by 50% depending on the judgment of the treating physician. For carboplatin dosage adjustment, see manufacturer's prescribing information.

(25) Dose adjustment for gemcitabine in combination with carboplatin for subsequent cycles is based upon observed toxicity. The dose of gemcitabine in subsequent cycles should be reduced to 800 mg/m.sup.2 on days 1 and 8 in case of any of the following hematologic toxicities: Absolute granulocyte count <500×10.sup.6/L for more than 5 days Absolute granulocyte count <100×10.sup.6/L for more than 3 days febrile neutropenia Platelets <25,000×10.sup.6/L Cycle delay of more than one week due to toxicity

(26) If any of the above toxicities recur after the initial dose reduction, for the subsequent cycle, gemcitabine should be given on day 1 only at 800 mg/m.sup.2.

(27) It is believed that cisplatin could be administered in a similar manner to carboplatin.

(28) In some instances dosage levels below the lower limit of the aforesaid range may be more than adequate, while in other cases still larger doses may be employed without causing any harmful side effect, and therefore the above dosage range is not intended to limit the scope of the invention in any way. It will be understood that the amount of the compound actually administered will be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound or compounds administered, the age, weight, and response of the individual patient, and the severity of the patient's symptoms.