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Sequential methotrexate and 5-Fluorouracil in advanced ovarian carcinoma
GYNECOLOGIC
ONCOLOGY
27, 90-96 (1987)
Sequential Methotrexate and 5-Fluorouracil in Advanced Ovarian Carcinoma Ross C. DONEHOWER, M.D. ,’ NEIL B. ROSENSHEIN, M.D., JACOB ROTMENSCH, M.D., AND DAVID S. ETTINGER, M.D. Division
of Gynecologic Oncology and The Johns Hopkins Hospital Oncology Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
Received February 26, 1986 Experimental studies have demonstrated that the combined effects of methotrexate and 5-FU may be optimized in schedules of administration where the antifolate is administered prior to the fluoropyrimidine. Seventeen patients with ovarian carcinoma refractory to standard chemotherapy were treated with a sequence of moderate dose MTX (200 mg/m’) and S-FU. No responses were seen, although the hematologic and gastrointestinal toxicity which was observed was very mild. Because of prior nephrotoxic chemotherapy and the frequent presence of large amounts of “third space” fluid in the form of malignant ascites, patients with ovarian cancer are at high risk for MTX toxicity. In this study, eight patients with significant ascites had higher plasma MTX concentrations measured at 48 and 72 hr following drug administration than nine similar patients without ascites. This suggested delayed excretion of MTX in patients with ascites although this difference was not statistically significant. MTX concentrations in ascites exceeded those in plasma between 6 and 12 hr and remained near 1 pM for 24 hr. Although the lack of response is disappointing, the modest toxicity encountered with the careful drug level monitoring and the favorable pharmacologic findings suggest that this combination of drugs each with established activity in untreated ovarian cancer deserves further study in primary treatment. o 1987 Academic Press, Inc.
Patients with advanced epithelial ovarian carcinoma treated initially with any of several combination chemotherapy regimens have a 57 to 84% chance of achieving a partial or complete remission [I]. Patients who fail to respond to initial therapy with either single agents or combinations, or whose disease progresses after an initial response have a low likelihood of achieving a meaningful response to “second line” therapy. When a patient with alkylating agent resistant ovarian cancer is treated with standard combinations of hexamethylmelamine (HMM),
’ To whom correspondence should be addressed: Johns Hopkins Oncology Center, Room l-121, 600 North Wolfe Street, Baltimore, MD. 21205.
90 0090-8258/87$1.50 Copyright All rights
0 1987 by Academic Press, Inc. of reproduction in any form reserved
MTX
AND
5-FU
IN OVARIAN
CANCER
91
doxorubicin (DOX), and cyclophosphamide (CTX) [2] or HMM, DOX, CTX, and cisplatin [3], or DOX, cisplatin and 5fluorouracil (5FU) [4]; the response rates range from 17 to 48% with median survivals all less than 1.5months. These results are clearly less favorable than those documented for similar combinations in previously untreated patients. A large number of single agents have similarly shown very disappointing results when used following a failure on initial therapy. This includes several agents used successfully in the standard combinations such as HMM with an S-28% response rate of 2.5-5.8 months duration [5-71 and DOX where no meaningful activity has been demonstrated [8,9]. This lack of effective salvage therapy remains a major clinical problem, and emphasizes the need to optimize the initial attempt at therapy. Methotrexate (MTX) and 5-FU have been commonly used together in combination chemotherapy for a variety of diseases, including ovarian cancer [lO,ll]. However, it has only been in the last few years that efforts have been made to optimize their combined effects. Work in a number of experimental chemotherapy systems has indicated that schedules of drug administration in which MTX precedes 5FU result in enhanced cytotoxicity, and several of the biochemical features of this important drug interaction have been characterized [12-151. A detailed discussion of this interaction or an exhaustive list of references pertaining to it is beyond the scope of this paper. However, they do firmly establish the rationale for testing the sequential use of the drugs. A number of studies have been done many of them in colon, breast, and head and neck cancers with somewhat conflicting results [16-221. Some of the discrepancy may be accounted for by the wide variation in doses of the drugs employed and the interval between MTX and 5-FU administration. The original studies by Bertino et al. and Cadman et al. [12,15] suggested that an interval as short as 1 hr was sufficient to enhance the combined drug effects in rapidly growing murine tumors. However, the bulk of current clinical and laboratory evidence suggests that longer intervals are necessary in the more slowly growing human solid tumors [14]. No studies have been reported in ovarian cancer and since both agents have activity in this disease this study was undertaken. In patients with ovarian cancer there is an additional concern with the use of MTX. This drug has been shown to distribute to “third spaces” such as pleural fluid and ascites and it has been suggested this may slow the elimination of the drug and greatly increase the risk of increased drug toxicity. Only one pharmacologic study examining MTX concentrations in ascites has been reported in similar patients using very low MTX doses [23]. This study had several purposes. First was to evaluate the efficacy of sequential MTX and 5-FU in refractory ovarian cancer. Second was to characterize the toxicity of this therapy in a group of patients with several important risk factors for MTX toxicity. It was hoped that moderate dose MTX and 5-FU could be given with minimal toxicity to this group. This would enable incorporation of this regimen into primary therapy with other drugs with potentially overlapping toxicities on the marrow and gastrointestinal tract. Third was to define the pharmacology and drug distribution of MTX in these patients.
92
DONEHOWER
ET AL.
MATERIALS AND METHODS Elegible patients for this study were those with a histologic diagnosis of an epithelial carcinoma of the ovary. All had received prior chemotherapy with a combination of DOX, CTX, and cisplatin. All patients had measurable disease by physical exam or radiographic studies. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 3 or less, a life expectancy of 1 month or greater, adequate bone marrow function (WBCs greater than 4000/mm3 platelets greater than 100,000/mm3), a creatinine clearance greater than 40 cc/min, and no chemotherapy within the preceding 4 weeks. MTX (200 mg/m’) was administered intravenously on Day 1 as a 1-hr infusion, 24 hr later 5-FU (600 mg/m*) was administered as an intravenous bolus. Citrovorum factor (10 mg/m*) was given orally or intravenously 2 hr after the S-FU administration, then orally, every 6 hr for at least 48 hr. Cycles were repeated every 14-21 days. Toxicity and responses was graded using the Eastern Cooperative Oncology Group (ECOG) scale [24]. Blood samples were drawn at 2,24,48, and 72 hr following MTX for determination of MTX concentration. In patients with ascites an attempt was made to obtain several samples for MTX concentrations. It was not possible in all patients to obtain paired ascites samples at all times blood was drawn. MTX concentrations were determined using a commercially available radioimmunoassay. (Diagnostic Biochemicals; San Diego, Calif.). The practical limit of sensitivity for this assay is approximately 1 nM. RESULTS Seventeen patients, with epithelial ovarian carcinoma (10 Stage 111and 7 Stage IV) who failed initial treatment with DOX, CTX, and cisplatin were treated with sequential MTX and 5-FU. Nine patients had papillary adenocarcinoma, seven had undifferentiated carcinoma, and one had a malignant Brenner tumor. All patients had evaluable disease in the form of palpable pelvic and abdominal masses or had measurable disease by CAT scan or ultrasound. The median age was 57 years (range 34-74 years). Performance status was assessed at the time of entry into the study using the Eastern Cooperative Oncology Group classification. The median PS was 1 (range O-2). Serum creatinine in all patints ranged from 0.5 to 1.5 prior to initiation of chemotherapy. Eight of the 17 patients had significant ascites which was clinically apparent. No objective responses were seen in these patients and all but one patient was evaluable for at least one course of therapy. Disease progression was documented in one patient after 10 cycles, three after 5 cycles, one after 4 cycles, three after 3 cycles, six after 2 cycles, and three after 1 cycle of MTX/S-FU. The median time to progression was 42 days or 2-3 cycles of therapy (range 21 to 210 days). The median survival from initiation of therapy for all patients was 3.0 months (range 0.5 to 11.0 months). Sequential MTX and 5-FU was well tolerated when given in this fashion, and no dose modification was required. The median of the lowest WBC and platelet counts recorded during the courses were 6000/mm3 (range 2500-18,000) and 224
MTX
AND
5-FU
IN
24
OVARIAN
48
CANCER
93
72
HOURS
FIG. 1. Plasma methotrexate concentrations measured in patients treated on this study at 2, 24, 48, and 72 hr following methotrexate administration. Mean concentrations at each time point are indicated by bays. x 103/mm3 (range loo-380 x 103). These characteristically occurred on Day 8, but since blood counts were only done on a weekly basis, lower values could have been missed. Only four courses had grade 2 leucopenia on the ECOG scale (WBC 2000-3000/ mm3). Only 4 of the 17 patients had nausea and/or vomiting and required antiemetics. Four patients developed grade 1 or 2 mucositis on multiple courses. No treatment-related deaths occurred. The plasma concentrations of MTX achieved during the first course of therapy in these patients are shown in Fig. 1. Because of the limited number of points available no detailed pharmacokinetic analysis was appropriate. In the nine patients without obvious ascites the mean of the plasma concentrations of MTX at 48 and 72 hr was 45.5 + 37.6 nM and 14.4 & 11.6 nM, respectively. This compares to values obtained in the eight patients with significant ascites of 73.3 rt 50.3 nM and 24.9 + 17.8 nM for the same time points. Because of the small numbers involved these differences do not reach statistical significance but do indicate a trend for delayed excretion of MTX in patients with significant ascites. The relationship between plasma and ascites MTX concentrations was studied in detail in two patients (Fig. 2). In both cases ascites concentrations exceeded
O.O1 w
-
24
48
FIG. 2. Methotrexate concentrations measured in plasma (3 and ascitic fluid (X) of two patients with significant ascites.
94
DONEHOWER ET AL.
those measured in plasma between 6 and 12 hr following drug administration and remained higher over the period studied. Both patients had MTX concentrations in ascitic fluid near 1 pit4 at 24 hr. DISCUSSION
Despite a well-established biochemical rationale for the use of MTX and 5FU in this sequence, no activity was seen in previously treated advanced epithelial ovarian cancer in this study. With the number of patients treated, statistically there is less than a 5% chance that a true response rate of 20% in this disease was missed in our study. Because the toxicity was so minimal, this cannot be considered a definitive phase II study. Other investigators using comparable doses and schedules in other diseases have given a similar combination on a more frequent basis, occasionally with formidable toxicity. The lower frequency of drug administration used in this study does not, however, preclude antitumor activity as demonstrated by other studies [181. This study does demonstrate that this sequence of MTX and 5-FU can be given with minimal toxicity to heavily pretreated patients. The activity of these drugs in previously untreated patients and their successful use in combination therapy [ IO,1 I] suggests that this sequence might warrant examination in initial chemotherapy regimens in combination with other agents. MTX concentrations exceeding l-30 ti have been shown to inhibit DNA synthesis in marrow and gastrointestinal mucosa, the major toxic sites for MTX in man [25]. Our data suggest that women with ascites may have delayed excretion and are at risk for prolonged exposure to toxic MTX concentrations. At the time leucovorin was discontinued in our study (72 hr), only three patients had plasma concentrations in excess of 30 ti and no significant toxicity occurred. Thus, this regimen can be given safely to these patients. We believe the minimal toxicity observed is the result of this careful monitoring of MTX concentrations in these patients and continued leucovorin rescue until nontoxic concentrations are reached. The studies reported here of plasma and ascites MTX concentrations support the findings of Chabner et al. at lower MTX doses [23]. Concentrations approaching 1 @4 were observed in ascites for 24 hr following drug administration. This is a concentration inhibitory to many tumors systems and if one can assume this reflects in part the exposure of the intraabdominal tumor to drug it may give added impetus to the use of higher MTX doses in ovarian cancer. Moderate dose MTX, slightly higher than that used in this study (750 mg/m’), has been used with moderate success in both previously treated and untreated patients by Barlow and co-workers [26,27]. That work and this study suggest that moderate dose MTX with sequential 5-FU deserve further investigation in ovarian cancer. REFERENCES 1. Young, R. C., Knapp, R. C., Fuks, Z., and DiSaia, P. J. Cancer of the ovary, in Cancer: principles and practice of oncology (V. T. DeVita, S. Hellman, and S. A. Rosenberg, Eds.), J. B. Lippincott Co., Philadelphia, pp. 1083-1118 (1985). 2. Sessa, C., Bolis, G., Valente, I., et al. Hexamethylmelamine, doxorubicin, and cyclophosphamide in advanced ovarian cancer resistant to previous chemotherapy, Cancer Treat. Rep. 65, 530531 (1981).
MTX
AND
5-FU
IN
OVARIAN
CANCER
95
3. Bruckner, H. W., Cohen, C. J., Deppe, G., et al. Treatment of chemotherapy-resistant advanced ovarian cancer with a combination of cyclophosphamide, hexamethylmelamine, adriamycin, and cis-diamminedichloroplatinum (CHAP), Gyneco/. Oncol. 12, 150-153 (1981). 4. Alberts, D. S., Hilgers, R. D., Moon, T. E., Martimbeau, P. W., and Rivkin, S. Combination chemotherapy for alkylator-resistant ovarian carcinoma: a preliminary report of a southwest oncology group trial, Cancer Treat. Rep. 63, 301-305 (1979). 5. Bolis, G., D’Incalci, M., Belloni, C., and Mangioni, C. Hexamethylmelamine in ovarian cancer resistant to cyclophosphamide and adriamycin, Cancer Treat. Rep. 63, 1375-1377 (1979). 6. Johnson, B. L., Fisher, R. I., Bender, R. A., DeVita, V.T., Chabner, B. A., and Young, R. C. Hexamethylmelamine in alkylating agent-resistant ovarian carcinoma, Cancer 42, 2157-2161 (1978). 7. Omura, G. A., Greco, F. A., and Birch, R. Hexamethylmelamine in mustard-resistant ovarian adenocarcinoma, Cancer Treat. Rep. 65, 530-531 (1981). 8. Bolis, G., D’Incalci, M., Gramellini, F., et al. Adriamycin in ovarian cancer patients resistant to cyclophosphamide, Eur. J. Cancer 14, 1401 (1978). 9. Hubbard, S. M., Barkes, P., and Young, R. C. Adriamycin therapy for advanced ovarian cancer after chemotherapy, Cancer Treat. Rep. 62, 1375-1377 (1978). 10. Young, R. C., Chabner, B. A., Hubbard, S. P., et al. Prospective trial of melphalan versus combination chemotherapy (Hexa-CAF) in ovarian adenocarcinoma, N. Engl. J. Med. 299, 1261-1266 (1978). I I. Neijt, J. P., Vanlindert, A. C. M., Vendrijk, C. P. J., et al. Hexa-CAF combination chemotherapy and other multiple drug regimens in advanced ovarian cancer, Neth. J. Med. 22, 28-35 (1979). 12. Cadman, E. C., Heimer, R., and Davis, L. Enhanced 5-fluorouracil nucleotide formation following methotrexate: biochemical explanation for drug synergism, Science 205, 1135-1137 (1979). 13. Donehower, R. C., Allegra, J. C., Lippman, M. E., and Chabner, B. A. Combined effects of methotrexate and 5-fluoropyrimidines on human breast cancer cells in serum-free culture, Eur. J. Cancer 16, 655-661 (1980).
14. Benz, C., Schoenberg, M., Choti, M., et al. Schedule-dependent cytotoxicity of methotrexate and 5-fluorouracil in human colon and breast tumour cell lines, /. C/in. Invest. 66, 1162-l 165 (1980). 15. Bertino, J. R., Sawicki, W. L., Lindquist, C. A., et al. Schedule dependent antitumor effects of methotrexate and 5-fluorouracil, Cancer Res. 37, 327-328 (1977). 16. Pitman, S. W., Kowal, C. D., and Bertino, J. R. Methotrexate and 5-fluorouracil in sequence in squamous head and neck cancer, Semin. Oncol. 10 (Suppl. 2), 15-19 (1983). 17. Browman, G. P., Archibald, S. D., Young, J. E. M., et al. Prospective randomized trial of onehour sequential versus simultaneous methotrexate and 5-fluorouracil in advanced head and neck cancer, J. Clin. Oncol. 1, 787-792 (1983). 18. Allegra, J. C., Woodcock, T. M., Richman, S. P., et al. A phase II trial of tamoxifen, premarin, methotrexate and 5-fluorouracil in advanced breast cancer, Breast Cancer Res. Treat. 2, 9399 (1982).
19. Eisenhduer, E. E., Bowman, D. M., Pritchard, K. I., et al. Tamoxifen and conjugated estrogens followed by sequenced methotrexate and 5-FU in refractory advanced breast cancer, Cancer Treat. Rep. 68, 1421-1422 (1984). 20. Herrmann, R., Spehn, J., Beyer, J. H., et al. Sequential methotrexate and 5-fluorouracil: improved response rates in metastatic colorectal cancer, J. C/in. Oncol. 2, 591-594 (1984). 21. Weinerman, B., Schachter, B., Schipper, H., et al. Sequential methotrexate and 5-FU in the treatment of colorectal cancer, Cancer Treat. Rep. 66, 1553-1555 (1982). 22. Coates, A. J., Tattersall, M. H. N., Swanson, C., et al. Combination chemotherapy with methotrexate and 5-fluorouracil: a prospective randomized clinical trial of order of administration, J. C/in. Oncol. 2, 756-761 (1984).
23. Chabner, B. A., Stoller, R. G., Hande, K. R., et ul. Methotrexate disposition in humans: case studies in ovarian cancer and following high dose infusion, Drug Metab. Rev. 8, 107-117 (1978).
24. Oken, M., Creech, R. H., Tormey, D. C., et al. Toxicity and response criteria of the Eastern Cooperative Oncology Group, Amer. J. C/in. Oncol. 5, 549-655 (1982).
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ET AL.
25. Chabner, B. A., and Young R. C. Threshold methotrexate concentration for in viva inhibition of DNA synthesis in normal and tumorous target tissues, J. Clin. Invest. 52, 1804-1811 (1973). 26. Barlow, J. J., and Piver, M. S. Methotrexate with citrovorum factor rescue, alone and in combination with cyclophosphamide in ovarian cancer, Cancer Treat. Rep. 60, 527-533 (1976). 27. Barlow. J. J., and Lele, S. B. Cisplatin-MECY (methotrexate-leucovorin rescue plus cyclophosphamide) versus cisplatin-CHAD as initial chemotherapy in stage III-IV ovarian adenocarcinoma, Cancer Treat. Rep. 68, 1433-1438 (1984).
ONCOLOGY
27, 90-96 (1987)
Sequential Methotrexate and 5-Fluorouracil in Advanced Ovarian Carcinoma Ross C. DONEHOWER, M.D. ,’ NEIL B. ROSENSHEIN, M.D., JACOB ROTMENSCH, M.D., AND DAVID S. ETTINGER, M.D. Division
of Gynecologic Oncology and The Johns Hopkins Hospital Oncology Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
Received February 26, 1986 Experimental studies have demonstrated that the combined effects of methotrexate and 5-FU may be optimized in schedules of administration where the antifolate is administered prior to the fluoropyrimidine. Seventeen patients with ovarian carcinoma refractory to standard chemotherapy were treated with a sequence of moderate dose MTX (200 mg/m’) and S-FU. No responses were seen, although the hematologic and gastrointestinal toxicity which was observed was very mild. Because of prior nephrotoxic chemotherapy and the frequent presence of large amounts of “third space” fluid in the form of malignant ascites, patients with ovarian cancer are at high risk for MTX toxicity. In this study, eight patients with significant ascites had higher plasma MTX concentrations measured at 48 and 72 hr following drug administration than nine similar patients without ascites. This suggested delayed excretion of MTX in patients with ascites although this difference was not statistically significant. MTX concentrations in ascites exceeded those in plasma between 6 and 12 hr and remained near 1 pM for 24 hr. Although the lack of response is disappointing, the modest toxicity encountered with the careful drug level monitoring and the favorable pharmacologic findings suggest that this combination of drugs each with established activity in untreated ovarian cancer deserves further study in primary treatment. o 1987 Academic Press, Inc.
Patients with advanced epithelial ovarian carcinoma treated initially with any of several combination chemotherapy regimens have a 57 to 84% chance of achieving a partial or complete remission [I]. Patients who fail to respond to initial therapy with either single agents or combinations, or whose disease progresses after an initial response have a low likelihood of achieving a meaningful response to “second line” therapy. When a patient with alkylating agent resistant ovarian cancer is treated with standard combinations of hexamethylmelamine (HMM),
’ To whom correspondence should be addressed: Johns Hopkins Oncology Center, Room l-121, 600 North Wolfe Street, Baltimore, MD. 21205.
90 0090-8258/87$1.50 Copyright All rights
0 1987 by Academic Press, Inc. of reproduction in any form reserved
MTX
AND
5-FU
IN OVARIAN
CANCER
91
doxorubicin (DOX), and cyclophosphamide (CTX) [2] or HMM, DOX, CTX, and cisplatin [3], or DOX, cisplatin and 5fluorouracil (5FU) [4]; the response rates range from 17 to 48% with median survivals all less than 1.5months. These results are clearly less favorable than those documented for similar combinations in previously untreated patients. A large number of single agents have similarly shown very disappointing results when used following a failure on initial therapy. This includes several agents used successfully in the standard combinations such as HMM with an S-28% response rate of 2.5-5.8 months duration [5-71 and DOX where no meaningful activity has been demonstrated [8,9]. This lack of effective salvage therapy remains a major clinical problem, and emphasizes the need to optimize the initial attempt at therapy. Methotrexate (MTX) and 5-FU have been commonly used together in combination chemotherapy for a variety of diseases, including ovarian cancer [lO,ll]. However, it has only been in the last few years that efforts have been made to optimize their combined effects. Work in a number of experimental chemotherapy systems has indicated that schedules of drug administration in which MTX precedes 5FU result in enhanced cytotoxicity, and several of the biochemical features of this important drug interaction have been characterized [12-151. A detailed discussion of this interaction or an exhaustive list of references pertaining to it is beyond the scope of this paper. However, they do firmly establish the rationale for testing the sequential use of the drugs. A number of studies have been done many of them in colon, breast, and head and neck cancers with somewhat conflicting results [16-221. Some of the discrepancy may be accounted for by the wide variation in doses of the drugs employed and the interval between MTX and 5-FU administration. The original studies by Bertino et al. and Cadman et al. [12,15] suggested that an interval as short as 1 hr was sufficient to enhance the combined drug effects in rapidly growing murine tumors. However, the bulk of current clinical and laboratory evidence suggests that longer intervals are necessary in the more slowly growing human solid tumors [14]. No studies have been reported in ovarian cancer and since both agents have activity in this disease this study was undertaken. In patients with ovarian cancer there is an additional concern with the use of MTX. This drug has been shown to distribute to “third spaces” such as pleural fluid and ascites and it has been suggested this may slow the elimination of the drug and greatly increase the risk of increased drug toxicity. Only one pharmacologic study examining MTX concentrations in ascites has been reported in similar patients using very low MTX doses [23]. This study had several purposes. First was to evaluate the efficacy of sequential MTX and 5-FU in refractory ovarian cancer. Second was to characterize the toxicity of this therapy in a group of patients with several important risk factors for MTX toxicity. It was hoped that moderate dose MTX and 5-FU could be given with minimal toxicity to this group. This would enable incorporation of this regimen into primary therapy with other drugs with potentially overlapping toxicities on the marrow and gastrointestinal tract. Third was to define the pharmacology and drug distribution of MTX in these patients.
92
DONEHOWER
ET AL.
MATERIALS AND METHODS Elegible patients for this study were those with a histologic diagnosis of an epithelial carcinoma of the ovary. All had received prior chemotherapy with a combination of DOX, CTX, and cisplatin. All patients had measurable disease by physical exam or radiographic studies. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 3 or less, a life expectancy of 1 month or greater, adequate bone marrow function (WBCs greater than 4000/mm3 platelets greater than 100,000/mm3), a creatinine clearance greater than 40 cc/min, and no chemotherapy within the preceding 4 weeks. MTX (200 mg/m’) was administered intravenously on Day 1 as a 1-hr infusion, 24 hr later 5-FU (600 mg/m*) was administered as an intravenous bolus. Citrovorum factor (10 mg/m*) was given orally or intravenously 2 hr after the S-FU administration, then orally, every 6 hr for at least 48 hr. Cycles were repeated every 14-21 days. Toxicity and responses was graded using the Eastern Cooperative Oncology Group (ECOG) scale [24]. Blood samples were drawn at 2,24,48, and 72 hr following MTX for determination of MTX concentration. In patients with ascites an attempt was made to obtain several samples for MTX concentrations. It was not possible in all patients to obtain paired ascites samples at all times blood was drawn. MTX concentrations were determined using a commercially available radioimmunoassay. (Diagnostic Biochemicals; San Diego, Calif.). The practical limit of sensitivity for this assay is approximately 1 nM. RESULTS Seventeen patients, with epithelial ovarian carcinoma (10 Stage 111and 7 Stage IV) who failed initial treatment with DOX, CTX, and cisplatin were treated with sequential MTX and 5-FU. Nine patients had papillary adenocarcinoma, seven had undifferentiated carcinoma, and one had a malignant Brenner tumor. All patients had evaluable disease in the form of palpable pelvic and abdominal masses or had measurable disease by CAT scan or ultrasound. The median age was 57 years (range 34-74 years). Performance status was assessed at the time of entry into the study using the Eastern Cooperative Oncology Group classification. The median PS was 1 (range O-2). Serum creatinine in all patints ranged from 0.5 to 1.5 prior to initiation of chemotherapy. Eight of the 17 patients had significant ascites which was clinically apparent. No objective responses were seen in these patients and all but one patient was evaluable for at least one course of therapy. Disease progression was documented in one patient after 10 cycles, three after 5 cycles, one after 4 cycles, three after 3 cycles, six after 2 cycles, and three after 1 cycle of MTX/S-FU. The median time to progression was 42 days or 2-3 cycles of therapy (range 21 to 210 days). The median survival from initiation of therapy for all patients was 3.0 months (range 0.5 to 11.0 months). Sequential MTX and 5-FU was well tolerated when given in this fashion, and no dose modification was required. The median of the lowest WBC and platelet counts recorded during the courses were 6000/mm3 (range 2500-18,000) and 224
MTX
AND
5-FU
IN
24
OVARIAN
48
CANCER
93
72
HOURS
FIG. 1. Plasma methotrexate concentrations measured in patients treated on this study at 2, 24, 48, and 72 hr following methotrexate administration. Mean concentrations at each time point are indicated by bays. x 103/mm3 (range loo-380 x 103). These characteristically occurred on Day 8, but since blood counts were only done on a weekly basis, lower values could have been missed. Only four courses had grade 2 leucopenia on the ECOG scale (WBC 2000-3000/ mm3). Only 4 of the 17 patients had nausea and/or vomiting and required antiemetics. Four patients developed grade 1 or 2 mucositis on multiple courses. No treatment-related deaths occurred. The plasma concentrations of MTX achieved during the first course of therapy in these patients are shown in Fig. 1. Because of the limited number of points available no detailed pharmacokinetic analysis was appropriate. In the nine patients without obvious ascites the mean of the plasma concentrations of MTX at 48 and 72 hr was 45.5 + 37.6 nM and 14.4 & 11.6 nM, respectively. This compares to values obtained in the eight patients with significant ascites of 73.3 rt 50.3 nM and 24.9 + 17.8 nM for the same time points. Because of the small numbers involved these differences do not reach statistical significance but do indicate a trend for delayed excretion of MTX in patients with significant ascites. The relationship between plasma and ascites MTX concentrations was studied in detail in two patients (Fig. 2). In both cases ascites concentrations exceeded
O.O1 w
-
24
48
FIG. 2. Methotrexate concentrations measured in plasma (3 and ascitic fluid (X) of two patients with significant ascites.
94
DONEHOWER ET AL.
those measured in plasma between 6 and 12 hr following drug administration and remained higher over the period studied. Both patients had MTX concentrations in ascitic fluid near 1 pit4 at 24 hr. DISCUSSION
Despite a well-established biochemical rationale for the use of MTX and 5FU in this sequence, no activity was seen in previously treated advanced epithelial ovarian cancer in this study. With the number of patients treated, statistically there is less than a 5% chance that a true response rate of 20% in this disease was missed in our study. Because the toxicity was so minimal, this cannot be considered a definitive phase II study. Other investigators using comparable doses and schedules in other diseases have given a similar combination on a more frequent basis, occasionally with formidable toxicity. The lower frequency of drug administration used in this study does not, however, preclude antitumor activity as demonstrated by other studies [181. This study does demonstrate that this sequence of MTX and 5-FU can be given with minimal toxicity to heavily pretreated patients. The activity of these drugs in previously untreated patients and their successful use in combination therapy [ IO,1 I] suggests that this sequence might warrant examination in initial chemotherapy regimens in combination with other agents. MTX concentrations exceeding l-30 ti have been shown to inhibit DNA synthesis in marrow and gastrointestinal mucosa, the major toxic sites for MTX in man [25]. Our data suggest that women with ascites may have delayed excretion and are at risk for prolonged exposure to toxic MTX concentrations. At the time leucovorin was discontinued in our study (72 hr), only three patients had plasma concentrations in excess of 30 ti and no significant toxicity occurred. Thus, this regimen can be given safely to these patients. We believe the minimal toxicity observed is the result of this careful monitoring of MTX concentrations in these patients and continued leucovorin rescue until nontoxic concentrations are reached. The studies reported here of plasma and ascites MTX concentrations support the findings of Chabner et al. at lower MTX doses [23]. Concentrations approaching 1 @4 were observed in ascites for 24 hr following drug administration. This is a concentration inhibitory to many tumors systems and if one can assume this reflects in part the exposure of the intraabdominal tumor to drug it may give added impetus to the use of higher MTX doses in ovarian cancer. Moderate dose MTX, slightly higher than that used in this study (750 mg/m’), has been used with moderate success in both previously treated and untreated patients by Barlow and co-workers [26,27]. That work and this study suggest that moderate dose MTX with sequential 5-FU deserve further investigation in ovarian cancer. REFERENCES 1. Young, R. C., Knapp, R. C., Fuks, Z., and DiSaia, P. J. Cancer of the ovary, in Cancer: principles and practice of oncology (V. T. DeVita, S. Hellman, and S. A. Rosenberg, Eds.), J. B. Lippincott Co., Philadelphia, pp. 1083-1118 (1985). 2. Sessa, C., Bolis, G., Valente, I., et al. Hexamethylmelamine, doxorubicin, and cyclophosphamide in advanced ovarian cancer resistant to previous chemotherapy, Cancer Treat. Rep. 65, 530531 (1981).
MTX
AND
5-FU
IN
OVARIAN
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95
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