A phase II study of high dose tamoxifen and weekly cisplatin in patients with metastatic melanoma.

We have previously demonstrated that the combination of tamoxifen and cisplatin has activity in patients with metastatic melanoma. In vitro studies have demonstrated that tamoxifen and cisplatin exhibit cytotoxic synergy in human melanoma cells and that this interaction is dependent on a tamoxifen effect. The mechanism of this effect is currently under investigation in in vitro studies. In an attempt to improve the complete response rate of this regimen, we initiated a phase II trial to determine the effect of the use of high dose tamoxifen and weekly cisplatin on the complete response rate, disease-free survival and overall survival. Tamoxifen was started on day 1 initially at a dose of 240 mg/day and continued until the patient was taken off treatment. This dose was subsequently lowered to 200 mg/day. Cisplatin (80 mg/m2) was begun on day 2 and repeated weekly for a total of 3 weeks. During week 4, the patient was not treated with cisplatin but was evaluated for response. If disease stabilization or regression was documented, the patient received a second 3 week cycle of cisplatin and was then re-evaluated for response. Patients with progressive disease at any evaluation were removed from the study. In 28 consecutive patients, the overall response rate was 32% (95% confidence interval 15.88-52.35%). One patient achieved a complete remission that lasted 22 months. All other responses were partial in nature. Toxicity was primarily nausea and vomiting. Two patients developed grade 2 renal toxicity. There were no episodes of deep venous thrombosis. This phase II study demonstrates that this combination has modest activity in patients with metastatic melanoma. However, this study failed to confirm our hypothesis that high dose tamoxifen would increase the complete response rate of this combination. While this combination has activity, the overall response rate is not significantly better that that observed with the original Dartmouth regimen and the toxicity is substantial. We do not recommend this dose and schedule for routine clinical use.

Melanoma thickness and histology predict sentinel lymph node status.

BACKGROUND: It remains unclear which patients with melanoma will benefit most from lymphatic mapping and sentinel lymphadenectomy. The purpose of this study is to determine whether primary melanoma histopathologic features could be applied to predict sentinel node status. METHODS: One hundred twelve patients underwent sentinel node biopsy between May 1995 and August 1999. Reported histologic features were assessed for predictive value by univariate and multivariate logistic regression. RESULTS: The sentinel node was located successfully in 105 of the 112 patients (94%). Twenty-one of these 105 patients (20%) had sentinel nodes that were positive for metastatic disease. Multivariate analyses revealed that tumor thickness greater than 1.5 mm (P = 0.01), ulceration (P <0.01), and lymphovascular invasion (P = 0.05) predicted the presence of micrometastases. CONCLUSIONS: The presence of unfavorable histopathology such as ulceration and lymphovascular invasion may identify a group of patients with thin melanomas who would benefit from sentinel lymphadenectomy.

The effect of tamoxifen and cisplatin on the disease-free and overall survival of patients with high risk malignant melanoma.

The adjuvant treatment of high-risk malignant melanoma remains problematic. Previously we reported moderate success in the treatment of metastatic disease using tamoxifen, cisplatin, dacarbazine and carmustine. Based upon data that suggested tamoxifen and cisplatin were the active agents in this regimen, we initiated a phase II trial of this combination in the adjuvant setting. We treated 153 patients with 4 cycles of tamoxifen (160 mg day(-1), days 1-7) and cisplatin (100 mg m(-2), day 2) for 28-day intervals. Patients received an anti-nausea regimen of dexamethasone with ondansetron or granisetron. During the first 2 years of follow-up, patients were evaluated every 2 months with a history, physical exam, laboratory work and computed tomography scans of the chest, abdomen and pelvis every 4 months. Thereafter, patients were evaluated every 3 months and radiographic studies were performed if necessary. Currently, with a median follow-up of 36 months, the disease-free survival (DFS) is 68.4% and overall survival (OS) is 84.5%. Kaplan-Meier analysis predicts a 5-year DFS of 62% with an OS of 79%. Relapses after 20 months have been rare. No effect of gender or number of positive lymph nodes was noted, however, stage of disease prior treatment was a factor. The major toxicity proved to be gastrointestinal in nature with nausea the most prevalent symptom. Minimal renal, haematologic and neurologic toxicity occurred. These preliminary results suggest that there is a positive impact of tamoxifen and cisplatin on both the DFS and OS of high-risk malignant melanoma patients. The 5-year projected DFS and OS compare favourably with those reported for the ECOG 1684 trial and warrant confirmation in a prospective randomized trial.

Increase in tumor GADD153 mRNA level following treatment correlates with response to paclitaxel.

PURPOSE: We investigated the relationship between the basal and treatment-induced change in the tumor expression of the drug resistance gene MDR1 and the cellular injury response gene GADD153, and clinical response to paclitaxel treatment. METHODS: MDR1 and GADD153 mRNA levels were measured by reverse transcriptase polymerase chain reaction (RT-PCR) in tumor samples obtained by fine needle aspiration biopsy from 14 patients before and 24 h after paclitaxel infusion. RESULTS: There was no difference between responders and non-responders with respect to either the basal MDR1 mRNA level or the change in MDR1 mRNA level at 24 h after treatment (P = 0.464). Likewise, there was no difference in basal GADD153 mRNA level between responders and non-responders. However, there was a significantly greater increase in GADD153 mRNA at 24 h in responders compared with non-responders (P = 0.005). An increase in GADD153 mRNA level of 1.5-fold or higher predicted response with a sensitivity of 86% and a specificity of 100%. CONCLUSIONS: An increase in GADD153 mRNA level reflects chemotherapy-induced damage sufficient to be manifest as a clinically detectable reduction in tumor volume. Measurement of the change in GADD153 mRNA level successfully identified patients destined to respond as early as 24 h post-treatment.

A phase II/pharmacokinetic trial of high-dose progesterone in combination with paclitaxel.

PURPOSE: The purpose of this study was to investigate the effect of high-dose progesterone, an inhibitor of P glycoprotein, on the pharmacokinetics and toxicity of paclitaxel. PATIENTS AND METHODS: A total of 29 patients with various tumors were treated with single-agent paclitaxel (125 mg/m2 administered over 3 h once every 3 weeks) until progression of disease, at which point high-dose progesterone (3 g administered i.v. over 24 h) was added to the paclitaxel treatment program in 20 patients (13 women, 7 men). Pharmacokinetic studies of paclitaxel administered alone and with progesterone were performed in eight patients. RESULTS: The pharmacokinetic parameters of paclitaxel were highly variable. High-dose progesterone increased the peak plasma levels (3.00 +/- 0.94 vs. 4.15 +/- 1.63 microM; P = 0.029; mean +/- SD) and the area under the curve (AUC; 14.3 +/- 4.75 vs. 17.3 +/- 5.59 microM x h; P = 0.006) of paclitaxel. The absolute neutrophil and platelet nadir counts did not differ significantly between the paclitaxel and the combined treatment cycles. Three of the 20 patients documented to have progressive disease on paclitaxel alone had partial responses when high-dose progesterone was added to the paclitaxel regimen. CONCLUSION: Progesterone had a statistically significant impact on the pharmacokinetics of paclitaxel. The addition of high-dose progesterone to paclitaxel is feasible, but the small number of patients prevents conclusions being drawn about the clinical efficacy of combined progesterone and paclitaxel.

Characterization of a human melanoma cell line with non-oestrogen receptor dependent tamoxifen resistance.

While investigating the mechanism of synergistic cytotoxicity between tamoxifen (TAM) and cisplatin (DDP) we developed a TAM-resistant variant of the human melanoma cell line T-289. We sought to characterize this cell line with respect to the effect of TAM resistance on a variety of different intracellular cell cycle control and apoptotic pathways. A TAM-resistant variant cell line (289 TAMs) was developed and the technique of Western analysis was to determine the changes in protein expression that occurred as a result of the development of TAM resistance. In this model, TAM resistance resulted in an increase in the detectable basal levels of cyclin E, GADD 153, p16, BAX, Bcl-XL, and wild-type and mutant p53, an increase in TAM induction of p16, and a decrease in the detectable basal levels of cyclin D1, p21 and p27. There were no detectable changes in the levels of pRb. In the TAM-resistant variant, p21 levels were essentially undetectable, while p27 was present and maintained its response to TAM Induction, albeit at a much lower level. This investigation demonstrates that the development of TAM resistance is associated with a change in the detectable levels of a variety of cell cycle control and apoptosis-related proteins. While the exact role that each change plays in the development of tamoxifen resistance remains to be determined, these data suggest that the development of resistance to a particular agent results in changes in multiple, seemingly unrelated pathways. These data have implications for future studies in both the laboratory and the clinic.

Phase I and pharmacokinetic study of intraperitoneal topotecan.

OBJECTIVE: To determine the maximum tolerated dose and pharmacokinetics of topotecan when administered by the intraperitoneal route. METHODS: A dose-escalating Phase I trial was conducted in which fifteen % of the total dose was given as an intraperitoneal bolus in two litres of D5W and the remainder was given as a continuous intraperitoneal infusion over 24 hours. Treatments were given every 21 days. Pharmacokinetic analyses were performed at the recommended phase II dose. RESULTS: Seventeen patients received a total of 43 cycles at 21-day intervals. The maximum tolerated dose was 4 mg/m2 and acute dose-limiting toxicity was neutropenia. Other toxicities included leukopenia, anemia, emesis, fever, and abdominal pain. Although no objective responses were achieved, five of ten patients with ascites had a decrease in fluid accumulation with administration of intraperitoneal topotecan. The recommended phase II dose is 3 mg/m2. Pharmacokinetic analysis performed at a dose of 3 mg/m2 demonstrated that elimination from the peritoneal cavity followed second-order kinetics with k1 = 1.6 hr(-1), k2 = 0.3 hr(-1) and first and second-phase half-lives of 0.49 and 2.7 hours, respectively. Plasma pharmacokinetic behavior was best described by first-order kinetics with k = 0.5 hr(-1) and a half-life of 3.9 hours. The pharmacologic advantage, expressed as the peritoneal to plasma AUC ratio was 31.2. CONCLUSIONS: Intraperitoneal administration of topotecan at 3 mg/m2 results in a substantial increase in drug exposure for the peritoneal cavity without compromising systemic exposure; this may be beneficial for the treatment of patients with ovarian cancer or intraperitoneal carcinomatosis.

Synergy between tamoxifen and cisplatin in human melanoma cells is dependent on the presence of antiestrogen-binding sites.

We have demonstrated previously that cisplatin (DDP) and tamoxifen (TAM) act synergistically to kill human melanoma T-289 cells, and that the observed synergy is lost in the 3-fold TAM-resistant subline, 289/TAM6. We have identified the intracellular antiestrogen-binding sites (AEBSs), defined by their ability to bind antiestrogens while having no affinity for estrogen, as a possible mediator of this synergy. We report here that [3H]TAM binds to AEBSs, as defined by the ability of N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine-HCl, an AEBS-specific ligand, to compete with [3H]TAM binding. Furthermore, we have characterized the number of binding sites and their affinity for [3H]TAM by Scatchard analysis in whole-cell lysates, microsomal fractions, and nuclear fractions of both cell lines by competing [3H]TAM binding with increasing concentrations of unlabeled TAM. These data demonstrate that the loss of a high-affinity AEBS from the nuclear fraction of the 289/TAM6 cell line correlates with the loss of synergy between DDP and TAM in these cells. This implicates AEBSs as a critical component of the mechanism that mediates the synergistic interaction of DDP and TAM in human melanoma cells.

Characterization of a sustained-release delivery system for combined cytokine/peptide vaccination using a poly-N-acetyl glucosamine-based polymer matrix.

Identification of tumor-associated antigens (TAAs) and their class I MHC-restricted epitopes now allows for the rational design of peptide-based cancer vaccines. A biocompatible system capable of sustained release of biologically relevant levels of cytokine and TAA peptide could provide a more effective microenvironment for antigen presentation. Our goal was to test a sustained-release cytokine/TAA peptide-based formulation using a highly purified polysaccharide [poly-N-acetyl glucosamine (p-GlcNAc)] polymer. Granulocyte-macrophage colony-stimulating factor (GM-CSF; 100 microgram) and MART-1(27-35) peptide (128 microgram in DMSO) were formulated into p-GlcNAc. Peptide release was assayed in vitro using interleukin 2 production from previously characterized MART-1(27-35)-specific Jurkat T cells (JRT22). GM-CSF release was assayed via ELISA and proliferation of M-07e (GM-CSF-dependent) cells. Local bioavailability of MART-1(27-35) peptide for uptake and presentation by antigen-presenting cells was demonstrated for up to 6 days (>0.5 microgram/ml). More than 1.0 microgram/ml GM-CSF was concomitantly released over the same period. Biocompatibility and local tissue response to p-GlcNAc releasing murine GM-CSF was determined in C57BL/6 mice via s.c. injection using murine GM-CSF (0. 2 microgram/ml) in 200 microliter of a 2.5% polymer gel. Significant lymphocytic and eosinophilic infiltration was observed 2-7 days after injection with polymer containing murine GM-CSF. The results of our studies show that this biocompatible system is capable of a sustained concomitant release of biologically active peptide and cytokine into the local microenvironment. These findings support further studies to validate a p-GlcNAc delivery system vehicle for a cytokine/TAA peptide-based cancer vaccine.

A phase I and pharmacokinetic study of high dose tamoxifen and weekly cisplatin in patients with metastatic melanoma.

BACKGROUND: The authors have previously demonstrated that tamoxifen (TAM) is synergistic with cisplatin (DDP) in patients with metastatic melanoma. In vitro studies have demonstrated that TAM/DDP synergy is dependent on a TAM effect that is currently under investigation. In an attempt to improve the complete response rate of this regimen, the authors initiated a Phase I trial to determine the maximum tolerated dose (MTD) of TAM that could be safely administered with weekly DDP. METHODS: TAM was started on Day 1 at a dose of 80 mg/day and was increased by 40 mg to the MTD in groups of 3 patients. DDP (80 mg/m2) was begun on Day 2 and repeated weekly for a total of 3 weeks. During Week 4, the patients were not treated with DDP but instead evaluated for response. If disease stabilization or regression was documented, the patients received a second 3-week cycle of DDP and were then reevaluated for response. Patients with progressive disease were removed from the study. RESULTS: In 25 consecutive patients, the overall response rate was 20%. No responses were observed in patients treated with TAM at a dose of <240 mg/day. Among 13 patients treated at or above this dose, there were 2 complete responses, 3 partial responses, 2 mixed responses, and 6 patients with progressive disease. The overall response rate for patients treated with 240 mg of TAM or higher was 38.5%. Dose-limiting toxicity, which occurred at a TAM dose of 280 mg/day, was primarily hematologic and gastrointestinal in nature. There was one toxic death (due to septic neutropenia) at this dose. There were no episodes of thrombosis. CONCLUSIONS: A TAM dose of 240 mg/day is the recommended Phase II dose. Based on the 38.5% overall response rate at this dose, the authors have initiated a Phase II study.

delta 12-Prostaglandin-J2 is cytotoxic in human malignancies and synergizes with both cisplatin and radiation.

We have been investigating the synergistic cytotoxic interactions between tamoxifen (TAM) and cisplatin (DDP) in human malignant cell lines. Recent data have demonstrated that TAM activates phospholipase D, which can increase the production of prostaglandin D2. Prostaglandin D2 has been shown to have growth inhibitory properties in several malignant cell lines. delta 12-Prostaglandin-J2 (delta 12-PG J2) is a derivative of prostaglandin D2 that has been shown to have similar inhibitory properties. We hypothesized that TAM may increase the production of delta 12-PG J2, which in turn may synergize with DDP. To begin our investigation of this interaction, we sought to determine if delta 12-PG J2 was cytotoxic and synergistic in our melanoma system and then expanded our observations to include a wide range of malignant cells. We have demonstrated that delta 12-PG J2 is cytotoxic to multiple malignant cell lines including melanoma, ovarian, prostate, colon, pancreas, small cell lung cancer, and breast cancer lines. The IC50s ranged from 0.70 microM (small cell lung cancer) to 3.30 microM (DDP-resistant melanoma). Additionally, delta 12-PG J2 exhibited synergistic cytotoxicity with both DDP and ionizing radiation. These data suggest that delta 12-PG J2 should be further evaluated in an in vivo model to confirm activity.

Determinants of tamoxifen sensitivity control the nature of the synergistic interaction between tamoxifen and cisplatin.

The cytotoxic effect of tamoxifen (TAM) was investigated in the T-289 melanoma cell line, as well as the 289 DDP3 cisplatin (DDP)-resistant and the 289 TAM6 TAM-resistant variant melanoma cell lines to determine the effect of drug resistance on synergy. T-289 melanoma cells were made DDP or TAM resistant through chronic exposure to increasing concentrations of the respective drugs. Whereas DDP resistance could be overcome by increasing the concentration of TAM, the development of TAM resistance completely abolished synergy. TAM resistance was not related to the development of estrogen receptors, decreased TAM uptake, or the increased expression of the mdr-1 gene. TAM did not inhibit the action of Topoisomerase 1; however, TAM did induce apoptosis in the 289 melanoma cells. In contrast, TAM did not induce apoptosis in the TAM-resistant variant 289 TAM6 cells. To our knowledge, these are the first data associating TAM resistance with the inhibition of apoptosis.

A phase II trial of intraperitoneal high-dose carboplatin and etoposide with granulocyte macrophage-colony stimulating factor support in patients with ovarian carcinoma.

Based upon results obtained in a Phase I study, we conducted a Phase II trial of high-dose CBDCA and etoposide administered via the intraperitoneal (IP) route in patients with ovarian cancer. CBDCA at a dose of 600 mg/m2 and etoposide at a dose of 400 mg/m2 were administered rapidly into the peritoneal cavity. The total dose of each agent was calculated and given daily over 3 days in amounts equal to one-third of the total dose. On day 1 of therapy, one-third of the dose was mixed in 2 liters of D5W and administered intraperitoneally as rapidly as possible. On days 2 and 3, one-third of the dose was mixed in 1 liter of D5W and administered similarly. GM-CSF was begun on day 4 as a subcutaneous injection at a dose of 500 micrograms/m2/day. A total 53 courses of treatment was administered to 18 patients; 9 of 13 patients (69%) with evaluable disease demonstrated evidence consistent with a partial response; however, the majority were response determined by a decrease in tumor marker (CA-125). One patient who had pathologic evidence of disease at second look laparotomy, but no measurable disease, was treated and shown at subsequent reexploration to have no further evidence of disease. This patient remains free of disease at 17+ months. The toxicity encountered in this trial was formidable, resulting in the removal of 78% of the patients from the study prior to completing 6 cycles of therapy.

Phase I trial of cisplatin in combination with glutathione.

We treated 16 patients in a phase I trial of escalating doses of intravenous cisplatin in combination with the chemoprotectant glutathione given every 21 days. Forty-three of 44 cycles (98%) were evaluable, 85% of cycles were given on time, and the median number of cycles per patient was 2. Dose-limiting nephrotoxicity was reached at a dose of 175 mg/M2 of cisplatin. Other toxicities included ototoxicity in 7 patients (44%) and grade 3 to 4 nausea and vomiting in 15 evaluable cycles (34.9%). Myelosuppression was infrequent. An increase to 175% of standard cisplatin dose intensity is attainable with the administration of glutathione; however, toxicity is substantial and the number of tolerated cycles is limited. Alternatives to the single bolus dose schedule studied in the present trial should be explored in order to better define the clinical utility of glutathione in combination with high-dose cisplatin.

A comparison of intravenous versus intraperitoneal chemotherapy for the initial treatment of ovarian cancer.

A phase III study was conducted comparing intraperitoneal (ip) versus intravenous (iv) cisplatin-based therapy for patients with newly diagnosed ovarian cancer to determine if the pharmacologic advantage of ip delivery could be translated into an improved response and survival rate. Twenty-nine patients were randomized to receive six cycles of ip cisplatin 200 mg/m2 plus ip etoposide 350 mg/m2 with iv thiosulfate protection given every 4 weeks; thirty-three patients were randomized to receive six cycles of iv cisplatin 100 mg/m2 plus iv cyclophosphamide 600 mg/m2 administered every 3 weeks. Patients were stratified by stage (IIC-IV) and size of residual disease (> or < or = 1 cm). The study was conducted in a community-wide setting. The complete response in evaluable patients was 48% in the ip group and 52% in the iv group. The surgical complete response rate for all patients on study, underestimated because not all patients in complete clinical remission had a second-look laparotomy, was 31% in the ip group and 33% in the iv group. There was no difference in the response rates between the treatment arms as a function of residual disease < or = or > 1 cm. With a median follow-up of 46 months (range 21-70 months) there is no difference in response duration or survival. Both regimens were well tolerated with comparable hematologic and nonhematologic toxicity.

Tamoxifen delays the development of resistance to cisplatin in human melanoma and ovarian cancer cell lines.

The development of resistance to cisplatin (DDP) occurs rapidly both in vitro and in vivo, and constitutes a major obstacle to effective therapy. We have previously demonstrated that there is a highly synergistic interaction between tamoxifen (TAM) and DDP against cell lines representative of three different human cancers: melanoma, ovarian carcinoma and small-cell lung cancer. The purpose of these studies was to determine if TAM interferes with the development of resistance to DDP. T-289 melanoma cells and 2008 ovarian cancer cells were cultured with increasing concentrations of DDP +/- TAM in an attempt to induce resistance to DDP. At various time points the cells were removed from culture and the degree of resistance to DDP was quantitated. Concurrent exposure to TAM and DDP decreased both the rate and the absolute magnitude of resistance to DDP in both melanoma and ovarian cancer cell lines. In the T-289 cell line the rate was decreased by a factor of 3.4 +/- 1.4 (P < 0.05), while in the 2008 cell line the rate was decreased by a factor of 2.4 (P < 0.01). TAM decreases the rate as well as the absolute magnitude of in vitro resistance to DDP in both melanoma and ovarian cancer cell lines. These data suggest that the concurrent administration of TAM and DDP may result in a delay in the development of resistance to DDP which may have important clinical implications in the design of DDP-containing regimens.

A phase I trial of intraperitoneal carboplatin and etoposide with granulocyte macrophage colony stimulating factor support in patients with intraabdominal malignancies.

BACKGROUND: Although somewhat controversial, there are data to suggest that patients with ovarian cancer may experience a survival advantage if the dose intensity of platinum-containing regimens can be maximized. Administration of chemotherapeutic agents via the intraperitoneal route offers the opportunity to increase dose intensity of several chemotherapeutic agents. METHODS: The authors conducted a Phase I trial of intraperitoneal carboplatin and etoposide in combination with granulocyte macrophage colony stimulating factor (GM-CSF) in an attempt to determine the maximum tolerated dose of carboplatin. The starting dose for carboplatin was 300 mg/m2 and for etoposide 400 mg/m2. The dose of carboplatin was escalated while the etoposide was maintained at the initial dose. The total dose of each agent was calculated and given daily over 3 days in amounts equal to one-third of the total dose. On day 1 of therapy, one-third of the dose was mixed in 2 liters of dextrose (D5W) and administered intraperitoneally (IP) as rapidly as possible. On Days 2 and 3, one-third of the dose was mixed in 1 liter of D5W and administered similarly. GM-CSF was begun on Day 4 as a subcutaneous injection at a dose of 500 micrograms/m2/d. RESULTS: Unacceptable hematologic toxicity was encountered at a carboplatin dose of 800 mg/m2; therefore, a carboplatin dose of 600 mg/m2 is recommended for Phase II studies. An overall response rate of 54% with a complete response rate of 17% was observed in patients with ovarian cancer. The overall response rate for all patients was 45%. CONCLUSION: Because of the significant toxicity encountered in this study, it is recommended that this regimen be used only in the context of a clinical study. The recommended Phase II study dose for this combination is carboplatin 600 mg/M2 and a total dose of etoposide 400 mg/M2 total dose given as three equal parts IP over 3 days. GM-CSF should begin on Day 4 at a dose of 500 micrograms/m2/day subcutaneously and should continue until the absolute neutrophil count is greater than 1000 granulocytes on 3 successive days.

Tamoxifen: is it useful in the treatment of patients with metastatic melanoma?

PURPOSE: We have attempted to review the data regarding the activity of tamoxifen (TAM) to clarify the role of this agent in the treatment of metastatic melanoma. METHODS: Using the Melvyl Medline system, we identified recent reports describing the results of clinical trials that used TAM either as a single agent or in combination with other cytotoxic agents. Additionally, we reviewed the abstracts from the 29th Annual Meeting of the American Society of Clinical Oncology held in May 1993. RESULTS: Numerous articles have reported an overall response rate of 47% (95% confidence limit, 39.25 to 54.75) when patients with metastatic melanoma are treated with the combination of dacarbazine (DTIC), carmustine (BCNU), cisplatin (DDP), and TAM (DBDT). Additionally, recent laboratory studies have reported that synergism between TAM and DDP is at least partially responsible for the success of this regimen. CONCLUSION: While TAM as a single agent is minimally active in treating patients with metastatic melanoma, when it is combined with DTIC, BCNU, and DDP, a marked improvement in the overall response rate is observed. Although a prospective randomized trial has yet to be completed, it appears that this four-drug combination has a higher overall and complete response (CR) rate when compared with single-agent DTIC. In light of the relatively modest toxicity observed with this regimen, the combination of DBDT represents a reasonable alternative to single-agent DTIC as first-line therapy for patients with metastatic melanoma.

Tamoxifen modulation of cisplatin cytotoxicity in human malignancies.

Recent clinical trials have indicated that addition of tamoxifen (TAM) to a combination of cisplatin (DDP), carmustine and dacarbazine markedly increases the overall objective response rate of patients with metastatic malignant melanoma. Previous studies have determined that there is remarkable synergy between TAM and DDP in a human melanoma cell line T-289. Using the technique of median effect analysis, in clonogenic assay, we observed a highly synergistic interaction between TAM and DDP. To determine whether or not this synergistic interaction was unique to human melanomas, or is generally observed in other types of malignancy, we examined the nature of this interaction using a human ovarian carcinoma and small cell lung cancer cell line. Synergy was observed in both cell lines. In the case of all 3 types of malignancy, synergy was observed at concentrations of both TAM and DDP that can be achieved in patients. Our results demonstrate that cytotoxic synergy between the DDP and TAM is observed in cell lines established from multiple types of human malignancies. It is important to note that the synergy between TAM and DDP is not dependent on the presence of estrogen or progesterone receptors. Since TAM is well tolerated by patients, it is particularly attractive as a potential agent with which to sensitize human tumors to DDP.