COMBINATION OF GOLD COMPLEXES WITH OLAPARIB OR OTHER PARP1/2 INHIBITORS FOR USE IN THE TREATMENT OF CANCER RESISTANT TO SAID PARP1/2 INHIBITORS

Abstract

The present application is concerned with gold complexes for use in treating cancer which is resistant to a known therapy. In some embodiments, the cancer is resistant to a first PARP inhibitor and/or the gold complex is for use in combination with a second PARP inhibitor.

Claims

1. A gold complex for use in treating a cancer which is resistant to a known cancer therapy.

2. The gold complex for use in accordance with claim 1, wherein the gold complex is a compound of Formula I, Formula II, Formula III, Formula IV or Formula V: ##STR00004## wherein R.sup.1 to R.sup.5 are each OR.sup.6, SR.sup.6, NR.sup.6R.sup.7 or SR.sup.8, and at least one of R.sup.1 to R.sup.5 is SR.sup.8; R.sup.6 and R.sup.7 are each independently H, COR.sup.9, a C.sub.1-C.sub.6 alkyl, a C.sub.1-C.sub.6 alkenyl or a C.sub.2-C.sub.6 alkynyl; R.sup.8 is Au or AuPR.sup.10R.sup.11R.sup.12; and R.sup.9 to R.sup.12 are each independently H, a C.sub.1-C.sub.6 alkyl, a C.sub.2-C.sub.6 alkenyl or a C.sub.2-C.sub.6 alkynyl; or a pharmaceutically acceptable salt, solvate, tautomeric form or polymorphic form thereof.

3. The gold complex for use according to claim 2, wherein the gold complex is a compound of Formula (I).

4. The gold complex for use according to claim 3, wherein the compound of Formula (I) is a compound of Formula (Ia): ##STR00005##

5. The gold complex for use according to claim 3 or claim 4, wherein R.sup.1 to R.sup.4 are each OR.sup.6.

6. The gold complex for use according to any one of claims 3 to 5, wherein R.sup.6, each time it occurs, is independently H or COR.sup.9 and R.sup.9, each time it occurs, is a C.sub.1-C.sub.3 alkyl.

7. The gold complex for use according to claim 6, wherein R.sup.6, each time it occurs, is COCH.sub.3.

8. The gold complex for use according to claim 6, wherein R.sup.6, each time it occurs, is H.

9. The gold complex for use according to any one of claims 3 to 8, wherein R.sup.8 is AuPR.sup.10R.sup.11R.sup.12 and R.sup.10 to R.sup.12 are each a C.sub.2-C.sub.4 alkyl.

10. The gold complex for use according to any one of claims 3 to 8, wherein R.sup.8 is Au.

11. The gold complex for use according to claim 1, wherein the gold complex is auranofin or aurothioglucose or a pharmaceutically acceptable salt, solvate, tautomeric form or polymorphic form thereof.

12. The gold complex for use according to any preceding claim, wherein the cancer is a solid tumour or solid cancer.

13. The gold complex for use according to any preceding claim, wherein the cancer is blood cancer, bowel cancer, brain cancer, breast cancer, cervical cancer, endometrial cancer, gastric cancer, liver cancer, lung cancer, ovarian cancer, pancreatic cancer, prostate cancer or skin cancer.

14. The gold complex for use according to any preceding claim, wherein the cancer is a cancer which is resistant to treatment by a first PARP inhibitor.

15. The gold complex for use according to claim 14, wherein a patient suffering from the cancer has previously been treated with the first PARP inhibitor.

16. The gold complex for use according to either claim 14 or claim 15, wherein the first PARP inhibitor is a first PARP1 inhibitor.

17. The gold complex for use according to any preceding claim, wherein the gold complex is for use in combination with a second PARP inhibitor.

18. The gold complex for use according to claim 17, wherein the second PARP inhibitor is a second PARP1 inhibitor.

19. The gold complex for use according to claim 18, wherein the second PARP1 inhibitor is aurothiomalate, aurothioglucose (ATG), rucaparib, olaparib, nirparib, talazoparib, veliparib, pamiparib, 2X-121 or auranofin.

20. The gold complex for use according to claim 19, wherein the second PARP1 inhibitor is rucaparib, olaparib, nirparib, talazoparib, veliparib or pamiparib.

21. A pharmaceutical composition for treating cancer comprising (i) a gold complex, (ii) a second PARP inhibitor, and (iii) a pharmaceutically acceptable vehicle.

22. A process for making the composition of claim 21, the process comprising contacting a therapeutically effective amount of (i) a gold complex, (ii) a second PARP inhibitor and (iii) a pharmaceutically acceptable vehicle.

Description

[0074] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying Figures, in which:—

[0075] FIG. 1 provides graphs showing the ability of (A) auranofin, (B) olaparib, (C) niraparib and (D) talazoparib to inhibit cell proliferation of wild type A2780 cells at different concentrations;

[0076] FIG. 2 provides graphs showing the ability of (A) auranofin, (B) olaparib, (C) niraparib and (D) talazoparib to inhibit cell proliferation of olaparib resistant A2780 cells at different concentrations;

[0077] FIG. 3 provides graphs showing the ability of the combination of auranofin and olaparib to inhibit cell proliferation of olaparib resistant A2780 cells at different concentrations;

[0078] FIG. 4 provides graphs showing the ability of the combination of auranofin and (A) niraparib or (B) talazoparib to inhibit cell proliferation of olaparib resistant A2780 cells at different concentrations;

[0079] FIG. 5 provides graphs showing the ability of (A) auranofin and (B) olaparib to inhibit cell proliferation of olaparib resistant HCC1937 cells at different concentrations;

[0080] FIG. 6 provides a graph showing the ability of the combination of auranofin and olaparib to inhibit cell proliferation of olaparib resistant HCC1937 cells at different concentrations;

[0081] FIG. 7 is a graph showing the ability of aurothioglucose (ATG) to inhibit cell proliferation of olaparib resistant A2780 cells at different concentrations; and

[0082] FIG. 8 provides graphs showing the ability of the combination of ATG at a concentration of 123.46 nM in combination with various concentration of (A) olaparib, (B) niraparib and (C) talazoparib to inhibit cell proliferation of olaparib resistant A2780 cells.

EXAMPLE 1—MEASURING THE ABILITY OF AURANOFIN AND VARIOUS PARP INHIBITORS (PARPIS) TO INHIBIT OLAPARIB RESISTANT A2780 OVARIAN CANCER CELLS

Methods

Preparing Cells Resistant to Olaparib

[0083] A2780 ovarian cancer cells (wild-type “WT”) were cultured in RPMI 1640 Medium with 10% Fetal Bovine Serum (FBS).

[0084] The A2780 cell line is an ovarian cancer cell line that was established from an ovarian endometroid adenocarcinoma tumour. The patient from whom the A2780 cell line was established, did not receive treatment for their tumour before tissue was taken, and so the cell line has not been exposed to any anticancer drugs or chemicals. It is commonly used as a model to observe the effects of, and test the potency of various chemicals, methods of delivery and treatments for ovarian cancer.

[0085] To obtain cells resistant to olaparib, the cells were cultured in cell culture medium (RPMI 1640 Medium with 10% FBS) supplemented with 20 μM olaparib for one month in order to generate A2780 cells resistant to olaparib (“R”). After a month the cells were continuously cultured in the cell culture medium (RPMI 1640 Medium with 10% FBS) supplemented with 10 μM olaparib prior to use and for up to two months to maintain the resistance.

Cell Seeding

[0086] The cells were harvested from a flask into cell culture medium (RPMI 1640 Medium with 10% FBS) and then counted. The cells were diluted with culture medium and 40 μL of cell suspension (1000 cells/well) was added into each well of a 384-well cell culture plate. The plate was covered with a lid and left at room temperature without shaking for 30 minutes. The plate was then transferred to an incubator at 37° C. and 5% CO.sub.2 and left overnight.

Compound Preparation and Treatment

[0087] Test compounds were dissolved at a concentration of 30 mM in DMSO to create a stock solution. 45 μL of the stock solution was transferred to a 384 pp-plate. A 3-fold, 10-point dilution was performed by transferring 15 μL of the compound solution into 30 μL DMSO by using TECAN (EVO200) liquid handler. The plate was then spun at room temperature at 1,000 RPM for 1 minute. 40 nL of the diluted compound was then transferred from the compound source plate into the cell plate. The cell plate was then covered with a lid and placed in an incubator at 37° C. and 5% CO.sub.2 and left for 120 hours. 72 hours after treatment with the compound detection was conducted as discussed below.

Detection

[0088] CellTiter Glo® reagents were thawed and equilibrated to room temperature. The cell plate was then removed from the incubator and equilibrated at room temperature for 15 minutes. 30 μL of the CellTiter Glo® reagents were then added into each well (at 1:1 to culture medium). The contents was mixed for 2 minutes on an orbital shaker to induce cell lysis and then the plates were allowed to incubate at room temperature for 30 minutes. Luminescence was then measured on an Envision reader (Perkin Elmer).

Data Analysis

[0089] The inhibition activity was calculated using the following formula:

Inhibition (%)=100×(Lum.sub.vehicle−Lum.sub.sample)/(Lum.sub.vehicle−Lum.sub.blank),

where Lum.sub.vehicle is the luminescence of cells treated with 0.1% DMSO and Lum.sub.blank is cells in the culture medium.

[0090] The IC.sub.50 was calculated by fitting the curve using Xlfit (v5.3.1.3), equation 201:

Y=Bottom+(Top−Bottom)/(1+10{circumflex over ( )}((Log IC50−X)*HillSlope))

Results

[0091] The results are shown in Tables 1 to 4 and FIGS. 1 and 2.

TABLE-US-00001 TABLE 1 Inhibition of proliferation of wildtype A2780 ovarian cancer cells by auranofin and olaparib Test Mean Inhibition (n = 3)/% Conc./nM Auranofin Olaparib Niraparib Talazoparib 0.06 0.39 0.69 0.17 −3.72 −0.65 0.51 −0.34 2.86 1.52 −1.87 0.36 0.03 6.64 4.57 −0.74 1.77 0.18 23.37 13.72 2.52 2.98 0.97 35.80 41.15 21.08 5.00 −0.46 46.34 123.46 56.32 12.51 3.18 56.34 370.37 86.25 11.87 12.27 64.48 1,111.11 98.39 24.63 25.03 71.38 3,333.33 100.15 39.88 48.63 76.54 10,000 100.17 62.69 66.23 77.63 30,000 100.20 70.80 73.33 78.90

TABLE-US-00002 TABLE 2 Inhibition of proliferation of olaparib resistant A2780 ovarian cancer cells by auranofin, olaparib, niraparib and talazoparib Test Mean Inhibition (n = 3)/% Conc./nM Auranofin Olaparib Niraparib Talazoparib 0.06 −1.98 5.28 0.17 0.32 −0.08 0.51 −2.36 6.18 1.52 4.64 1.01 2.95 2.33 4.57 3.42 2.74 −0.19 3.63 13.72 12.34 1.78 −1.43 4.9 41.15 41.07 1.43 0.1 −1.18 123.46 78.31 5.53 −0.8 2.95 370.37 96.38 5.11 −0.56 9.21 1,111.11 96.82 2.24 −1.37 15.45 3,333.33 100.13 6.97 5.54 34.89 10,000 100.19 9.9 18.95 49.04 30,000 100.17 16.23 43.86 64.27

TABLE-US-00003 TABLE 3 IC.sub.50 for auranofin, olaparib, niraparib and talazoparib in wildtype and olaparib resistance A2780 cells Auranofin Olaparib Niraparib Talazoparib IC.sub.50 in wild-type 101 3,889 2,087 19 A2780 cells/nM IC.sub.50 in olaparib 55 >30,000 17,272 4,314 resistant A2780 cells/nM

TABLE-US-00004 TABLE 4 Maximum proliferation inhibition for auranofin, olaparib, niraparib and talazoparib for concentration ranges between 0.06 nM and 30,000 nM in wildtype and olaparib resistance A2780 cells Auranofin Olaparib Niraparib Talazoparib Maximum 100 72 75 80 inhibition observed in wild-type A2780 cells/% Maximum 100 23 47 66 inhibition observed in olaparib resistant A2780 cells/%

[0092] Surprisingly, auranofin appears to be a better inhibitor of proliferation of the olaparib resistant cells than of the wildtype cells, and achieved 100% inhibition for both.

[0093] Meanwhile, it is clear from the data provided above that the olaparib resistant cells are also resistant to niraparib and talazoparib. This is due to the same resistance mechanism occurring for all three inhibitors in this case. Accordingly, switching a patient from olaparib monotherapy to niraparib or talazoparib monotherapy would not be successful in this case.

EXAMPLE 2—MEASURING THE ABILITY OF A COMBINATION OF AURANOFIN AND A PARPI TO INHIBIT THE PROLIFERATION OF OLAPARIB RESISTANT A2780 OVARIAN CANCER CELLS

Methods

[0094] The methods were as described in example 1. In each test, the cells were treated with a combination or auranofin and olaparib. The concentration of auranofin was kept constant while the concentration of olaparib was varied.

[0095] All tests were run in triplicate and the mean inhibition calculated.

Data Analysis

[0096] Synergy or antagonism in mixtures may be assessed using the Colby approach. Using this approach calculates an expected result (E) for a mixture of A and B if there is no synergy or antagonism. E may be calculated using the following equation:

E=X+Y−XY/100

[0097] Where X is the observed result for compound A and Y is the observed result for compound B. If the observed value is greater than E then this demonstrates synergy.

Results

[0098] The results are shown in Tables 5 and 6 and FIGS. 3 and 4.

TABLE-US-00005 TABLE 5 Inhibition of proliferation of olaparib resistant A2780 ovarian cancer cells by the combination of auranofin and olaparib Olaparib in Olaparib in Olaparib in combination with combination with combination with Test 13.72 nM auranofin 41.15 nM auranofin 123.46 nM auranofin Conc. of Expected Observed Expected Observed Expected Observed Olaparib/nM Inhibition/% Inhibition/% Inhibition/% Inhibition/% Inhibition/% Inhibition/% 0.06 20.68 53.14 87.16 0.17 18.37 57.27 85.15 0.51 27.82 59.03 90.67 1.52 13.23 16.27 41.67 59.59 78.53 86.37 4.57 14.74 27.26 42.68 53.07 78.90 86.16 13.72 13.90 19.23 42.12 58.18 78.70 87.48 41.15 13.59 26.16 41.91 56.57 78.62 88.04 123.46 17.19 12.31 44.33 54.50 79.51 88.87 370.37 16.82 24.90 44.08 52.41 79.42 86.8o 1,111.11 14.30 23.42 42.39 52.55 78.80 88.85 3,333.33 18.45 23.22 45.18 56.45 79.82 88.29 10,000 21.02 35.24 46.90 51.71 80.46 87.61 30,000 26.57 35.97 50.63 60.26 81.83 88.08

TABLE-US-00006 TABLE 6 Inhibition of proliferation of olaparib resistant A2780 ovarian cancer cells by the combination of auranofin and niraparib or talazoparib Niraparib in Talazoparib in combination with combination with Test 123.46 nM auranofin 123.46 nM auranofin Conc. of Expected Observed Expected Observed PARPi/nM Inhibition/% Inhibition/% Inhibition/% Inhibition/% 0.06 77.88 90.25 83.59 85.86 0.17 78.38 89.77 78.23 90.04 0.51 77.80 89.04 84.49 86.88 1.52 78.95 86.82 80.64 87.09 4.57 78.27 86.43 81.94 89.75 13.72 78.00 86.92 83.21 85.08 41.15 78.33 88.11 77.13 87.26 123.46 78.14 85.74 81.26 89.90

[0099] The observed proliferation inhibition for the combination of auranofin and a PARPi was consistently higher than the expected values. This indicates that the combination of auranofin and a PARAi exhibits a synergistic effect on the olaparib resistant cells.

[0100] The expected values could not be calculated for lower concentrations of olaparib, due to no tests having been conducted to provide the percentage inhibition for olaparib as the sole active agent at these concentrations. However, the observed inhibition is still relatively high, indicating that a synergistic effect is observed down to concentrations of 60 pM olaparib. This conclusion is reinforced by the observed values being significantly higher than the expected values for the lower concentrations of niraparib and talazoparib.

[0101] The above results are particularly surprising given that you would not expect cells which are resistant to a PARPi when used alone to display sensitivity to it in combination with a second active agent.

EXAMPLE 3—MEASURING THE ABILITY OF A COMBINATION OF AURANOFIN AND OLAPARIB TO INHIBIT OLAPARIB RESISTANT HCC1937 TRIPLE NEGATIVE BREAST CANCER CELLS

Methods

[0102] The methods were as described in examples 1 and 2, except the HCC1937 cell line was used.

[0103] The HCC1937 cell line was established from a primary breast carcinoma from a 24-year-old patient with a germ-line BRCA1 mutation. It is an example of a triple-negative breast cancer (TNBC) cell line. Breast cancer patients routinely have the expression of estrogen receptor (ER), progesterone receptor (PR), and amplification of HER-2/Neu evaluated. These markers allow classification of breast cancer tumours as hormone receptor positive tumours, HER-2/Neu amplified tumours, and those tumours which do not express ER, PR, and do not have HER-2/Neu amplification. The latter group is referred to as triple-negative breast cancer based on the lack of these three molecular markers. TNBC represents approximately 10-15% of all breast cancers and patients with TNBC have a poor outcome compared to the other subtypes of breast cancer.

Results

[0104] The results are shown in Tables 7 and 8 and FIGS. 5 and 6.

TABLE-US-00007 TABLE 7 Inhibition of proliferation of olaparib resistant HCC1937 triple negative breast cancer cells by auranofin and olaparib Test Mean Inhibition (n = 3)/% Conc./nM Auranofin Olaparib 1.52 −8.11 −6.55 4.57 0.54 −1.82 13.72 −0.91 −3.47 41.15 0.49 −0.93 123.46 0.54 1.32 370.37 13.11 4.41 1,111.11 59.64 3.09 3,333.33 98.95 4.90 10,000 100.03 17.02 30,000 99.97 11.84

TABLE-US-00008 TABLE 8 Inhibition of proliferation of olaparib resistant HCC1937 triple negative breast cancer cells by auranofin at a concentration of 370.37 nM and olaparib at varying concentrations Test Conc. of Expected Observed Olaparib/nM Inhibition/% Inhibition/% 1.52 7.42 17.01 4.57 11.53 13.23 13.72 10.09 21.04 41.15 12.30 16.65 123.46 14.26 26.96 370.37 16.94 17.08 1,111.11 15.79 23.22 3,333.33 17.37 28.82 10,000 27.90 26.40 30,000 23.40 49.22

[0105] Similar to the results observed in Example 2, a synergistic effect is also observed for the combination of olaparib and auranofin. It is noted that this effect is not observed for the results where olaparib was used at a concentration of 10,000 nM. However, since a synergistic effect is observed at both higher and lower concentrations of olaparib, it is thought that this one result is most likely due to experimental error.

[0106] Accordingly, the results show that the combination of auranofin and a PARPi may be used synergistically to inhibit proliferation of multiple cancer cell lines.

EXAMPLE 4—MEASURING THE ABILITY OF A COMBINATION OF AUROTHIOGLUCOSE AND PARPIS TO INHIBIT PROLIFERATION OF OLAPARIB RESISTANT A2780 OVARIAN CANCER CELLS

Methods

[0107] The methods were as described in examples 1 and 2, except aurothioglucose was used instead of auranofin was used.

Results

[0108] The ability of olaparib, niraparib and talazoparib to inhibit proliferation of olaparib resistant A2780 ovarian cancer cells is provided in table 2 (above). Meanwhile, the ability of aurothioglucose (ATG) to inhibit these cells is provided in Table 9 and FIG. 7.

TABLE-US-00009 TABLE 9 Inhibition of proliferation of olaparib resistant A2780 ovarian cancer cells by aurothioglucose Mean Inhibition Test Conc./nM (n = 3)/% 1.52 1.52 4.57 −11.62 13.72 1.10 41.15 6.50 123.46 11.16 370.37 18.52 1,111.11 23.75 3,333.33 16.36 10,000 19.40 30,000 29.94

[0109] The inhibitor effect of ATG in combination with a PARPi was also investigated and the results are provided in Table 10 and FIG. 8.

TABLE-US-00010 TABLE 10 Inhibition of proliferation of olaparib resistant A2780 ovarian cancer cells by aurothioglucose at a concentration of 123.46 nM in combination with a PARPi at various concentrations Olaparib in Niraparib in Talazoparib in combination with combination with combination with Test 123.46 nM ATG 123.46 nM ATG 123.46 nM ATG Conc. of Expected Observed Expected Observed Expected Observed PARPi/nM Inhibition/% Inhibition/% Inhibition/% Inhibition/% Inhibition/% Inhibition/% 0.06 33.43 29.51 25.33 0.17 25.52 28.18 20.25 0.51 30.68 27.23 32.03 1.52 12.06 20.97 13.78 27.95 13.23 25.49 4.57 13.59 37.97 10.99 25.94 14.38 26.63 13.72 12.74 32.22 9.89 24.16 15.51 25.74 41.15 12.43 31.69 11.25 20.61 10.11 23.68 123.46 16.07 28.99 10.45 22.60 13.78 27.40 370.37 15.70 28.48 10.66 27.00 19.34 32.25 1,111.11 13.15 23.90 9.94 27.03 24.89 32.24 3,333.33 17.35 28.82 16.08 26.67 42.16 43.05 10,000 19.96 40.20 28.00 35.25 54.73 57.40 30,000 25.58 40.90 50.13 50.90 68.26 66.71

[0110] Again, a clear synergistic effect is observed. This indicates that the synergistic effect is not limited to auranofin, but may be extended to further gold complexes in combination with a PARPi.