Overview of docetaxel (Taxotere)/cisplatin combination in non-small cell lung cancer.

Cisplatin-based chemotherapy is effective in non-small cell lung cancer (NSCLC), although it prolongs survival only modestly. Single-agent docetaxel (Taxotere; Rhône-Poulenc Rorer, Antony, France) is highly active against NSCLC. The activity and tolerability of two docetaxel/ cisplatin regimens were therefore investigated in two multicenter phase II studies, one in Australia and one in France. Chemotherapy-naive patients with inoperable NSCLC received either docetaxel 75 mg/m2 on day 1 plus cisplatin 75 mg/m2 3 weekly (n = 47; Australian study) or docetaxel 75 mg/m2 on day 1 plus cisplatin 100 mg/m2 every 3 weeks for three cycles then every 6 weeks (n = 51; French study). The majority of the population (74%) had metastatic disease. Seventy-eight patients were evaluable for efficacy. Overall response rates were 36% (95% confidence interval, 25 to 47) in all evaluable patients and 34% in patients with metastases. Median duration of response was 6 months, with a 4-month median time to progression. Median survival time was 9 months, with a 1-year survival rate of 34%. A median of four (range, one to nine) treatment cycles were administered. Febrile neutropenia occurred in 14% of patients. Severe infection, which occurred in less than 7% of patients, led to two toxic deaths. Other severe toxicities were rare, with severe stomatitis and severe neurosensory side effects reported in 2% and 1%, respectively, of treated patients. No severe fluid retention occurred. Docetaxel/cisplatin, administered as two different schedules, is well tolerated and exhibits efficacy in the range of the most established combinations in the treatment of advanced NSCLC.

Docetaxel in the community setting: an analysis of 377 breast cancer patients treated with docetaxel (Taxotere) in the UK. UK Study Group.

BACKGROUND: Given as first- or second-line chemotherapy docetaxel appears to have great potential in advanced breast cancer. PATIENTS AND METHODS: Three hundred and seventy-seven locally advanced or metastatic breast cancer patients received docetaxel (Taxotere) as part of a named patient programme under the care of 108 oncologists from 61 cancer units across the UK. The recommended starting dose was 100 mg/m2, but patients at higher risk of toxicity started at 75 mg/m2. All patients received corticosteroid premedication. The modal number of prior chemotherapy regimens was 2 (range 1-7). 342 patients (91%) had at least one prior anthracycline-based regimen. RESULTS: Response was graded according to the managing clinician's best judgement without formal criteria. The overall response rate (ORR) was 46% among the 331 evaluable patients. 46% among the 299 patients who were anthracycline resistant and 35% among the 82 patients who were anthracycline refractory (progressive disease being the best response obtained to the most recent anthracycline containing regimen). One hundred and ninety-three patients started at the full dose of 100 mg/m2 with an ORR of 55% and 129 started at 75 mg m2 with an ORR of 33%. In October 1997, some two years after the programme had started, 26 of 377 patients were still alive, although no complete remissions have lasted to this date. Kaplan-Meier survival analysis yielded a median survival of 194 days (95% CI: 178-218 days). Haematological parameters were checked before each course of docetaxel and additionally as clinically indicated. The safety data confirmed that docetaxel has a manageable, predictable side effect profile; 29 of 377 (7.7%) patients were hospitalised as a result of neutropenic sepsis. CONCLUSIONS: The results of this named patient programme over a two year timespan confirm that docetaxel is an effective chemotherapy option in patients with locally advanced and/or metastatic breast cancer, including an 'anthracycline refractory' population.

Combined treatment with dacarbazine, cisplatin, fotemustine and tamoxifen in metastatic malignant melanoma.

The combination of dacarbazine (DTIC), cisplatin (DDP), carmustine and tamoxifen (TAM) has been reported to yield a high rate of response in patients with metastatic melanoma, but responders often experience intracranial recurrences. As fotemustine (FOT) has demonstrated activity on cerebral metastases, the rationale of this study was to replace carmustine by FOT in this four-drug regimen. Twenty patients with metastatic melanoma received FOT (100 mg/m2) on days 1 and 8, DTIC (220 mg/m2 per day) and DDP (25 mg/m2 per day) from day 1 to day 3 and from day 28 to day 30, and continuous daily treatment with TAM (20 mg/day). If stabilization or response was observed at the end of the 8th week, patients received maintenance courses of FOT on day 1, and DTIC (220 mg/m2 per day) and DDP (25 mg/m2 per day) on days 1 to 3. Nineteen patients were evaluable. Of these, six had brain metastases. The overall response rate was 10.5% (two out of 19); both of the responders had only partial responses. The best responding site was lung. No response was obtained in the four patients with evaluable brain metastases, but no patient had therapy failure due to new brain metastases. The median overall survival was 5 months (range 1-45 months). Toxicity was mainly haematological. The use of this combination is not recommended.

Fotemustine, dacarbazine, vindesine combination chemotherapy in advanced malignant melanoma: a phase II study of 43 patients.

Fotemustine and dacarbazine constitute the most active single chemotherapeutic agents in the treatment of melanoma. In this phase II study we evaluated the activity and toxicity of a combination of fotemustine, dacarbazine and vindesine as a means of increasing response rate and survival time. Between September 1989 and November 1993, 43 patients with advanced melanoma were treated with a combination of 100 mg/m2 fotemustine on days 1 and 8, 250 mg/m2 dacarbazine on days 15 and 16 and 2 mg/m2 vindesine on days 15 and 16 as induction treatment. After a 5-week rest period, the patients exhibiting a response or stable disease received the same drugs administered once every 28 days as maintenance therapy until either progression or toxicity was observed. Among 41 evaluable patients, there were six complete responses and eight partial responses. The overall response rate was 32% (95% confidence interval: 18-46%), with 8 months median duration of response. Median survival time was 10 months. This regimen was well tolerated. From this large phase II study, we conclude that such a combination is active against advanced malignant melanoma and seems to be more effective than fotemustine or dacarbazine used alone, especially on visceral metastatic sites.

In vitro activity of S 9788 on a multidrug-resistant leukemic cell line and on normal hematopoietic cells-reversal of multidrug resistance by sera from phase I-treated patients.

The triazinoaminopiperidine derivative S 9788 is a new multidrug-resistance modulator that is currently being evaluated in phase I clinical trials. In this study, the reversal effect of S 9788 in comparison with verapamil was shown in vitro in human T-leukemic CCRF-CEM/VLB cells expressing the multidrug-resistance (MDR) phenotype. S 9788 increased in a dose-dependent manner the cytotoxic activity of doxorubicin or vinblastine, with complete reversal of resistance occurring at 2 microM for a concomitant continuous exposure (96 h) to the cytotoxic drugs. At respective concentrations equivalent to the IC10 value (the concentration inhibiting 10% of cell growth), S 9788 was 44 times more potent than verapamil in CCRF-CEM/VLB cells. S 9788 at 2 microM did not enhance the in vitro toxicity of doxorubicin or vinblastine in the human normal bone-marrow erythroid (BFU-E) and myeloid (CFU-GM) progenitors. The effect of exposure duration and concentrations on the synergistic action of modulator and cytotoxic agent closely depended on the cytotoxic agent studied. Post-incubations with S 9788 alone after a 1-h coadministration with vinblastine and S 9788 dramatically increased the reversal effect (4-41 times) in proportion to both the duration of postincubation and the concentration of S 9788. In contrast, for doxorubicin resistance, post-incubation with S 9788 alone induced a maximal 2-fold increase in the reversal effect that was not proportional to the post-incubation duration. In patients treated with S 9788 as a 30-min intravenous infusion during phase I trials, a good correlation was found between the serum levels of S 9788 and the ability to reverse MDR in CCRF-CEM/VLB cells. The reversal effect was dose-dependent and was effective beginning at a plasma concentration of 0.25 microM. These data form a basis for the design of phase II trials using a combination of a loading dose of S 9788 given before vinblastine or doxorubicin administration followed by a maintenance infusion of S 9788 alone for a period of 2-24 h.

[Tamoxifen increases cytotoxic effects of fotemustine. Experimental results on cell lines of human melanoma]. / Le tamoxifène augmente les effets cytotoxiques de la fotémustine. Résultats expérimentaux sur lignées de mélanomes humains.

Fotemustine (Fote) is a new aminoacid linked chloroethyl nitrosourea which has been shown to be useful in disseminated malignant melanoma. The aim of the present study was to analyze the cytotoxic effects resulting from the combination of antiestrogens and Fote on human melanoma cell lines. The antiestrogens tested were tamoxifen (TMX 5.10(-7) M and 5.10(-6) M) and 40H TMX (5.10(-8) M and 5.10(-7) M). As a preliminary step, a series of nine human melanoma cell lines was screened in order to identify and quantify the presence of estradiol receptors (ER) in these cell lines. This led to selecting an ER positive (+) cell line. The drugs alone or in combination were then tested against CAL 1 ER (+) and CAL 7 ER (-) melanoma cell lines. Different sequences of drug combinations were tested using clinically compatible drug concentrations. For CAL 1 cells there was a growth inhibitory effect induced by the antiestrogens given alone. Overall, the presence of the antiestrogens resulted in higher cytotoxic effects than when cells were exposed to Fote alone. The lowest IC50 Fote values as compared to Fote alone were generated by the sequences with the antiestrogens administered before Fote. Significantly, these associations with antiestrogens enabled the IC50 values of Fote to be reduced up to 80%. Globally TMX and 40H TMX had similar synergistic effects. TMX and 40H TMX had a modest influence on Fote cytotoxic effects against CAL 7 ER (-) cells. These data may be useful for optimal planning of future clinical trials for malignant melanoma using antiestrogens and nitrosoureas.

Phase II study of nitrosourea fotemustine as single-drug chemotherapy in poor-prognosis non-small-cell lung cancer.

A phase II study was designed to evaluate objective response rate and toxicity of fotemustine as single-drug chemotherapy in non-small-cell lung cancer. Eighty-seven patients with unresectable non-small-cell lung cancer took part in the study. Seventy-seven were evaluable for response. Of these, 60% had received prior chemotherapy and 74% had metastatic disease. Moreover, 22 patients had central nervous system metastases (of whom 12 were evaluable for this site). Treatment consisted of fotemustine 100 mg m-2 administered on days 1 and 8 followed by a 5 week rest period. Afterwards, responding or stabilised patients received fotemustine 100 mg m-2 every 3 weeks as a maintenance therapy. Toxicity and quality of life were recorded during therapy. Thirteen patients (17%; 95% CI 9-25%) had an objective response (11% for pretreated, 26% for non-pretreated) with a median duration of 22 weeks (range 7-41 weeks). Two objective responses were observed among the 12 patients with evaluable brain metastases. No response was observed among the 14 patients with adenocarcinoma. Haematological, gastrointestinal, hepatic and renal toxicities were mild to moderate and manageable. The most frequent biological adverse reactions were delayed thrombocytopenia and neutropenia. Quality of life did not significantly decrease during the first 6 treatment weeks. Moreover, it remained stable during the study period in patients with response or stabilisation, whereas it significantly decreased in patients who experienced progression of the disease. Fotemustine is feasible for single-drug chemotherapy in non-small-cell lung cancer even though poor prognostic variables such as brain metastases are present. It can be administered on an outpatient basis and toxicity is moderate and manageable. Thus, fotemustine can be considered as a putative drug in further combinations.

Multidrug resistance circumvention by a new triazinoaminopiperidine derivative S9788 in vitro: definition of the optimal schedule and comparison with verapamil.

The current work was undertaken to investigate the importance of exposure sequence and duration in achieving the maximum reversal action of S9788 on doxorubicin (DOX) cytotoxicity against cells that exhibit the (MDR) multidrug resistance phenotype: the MCF7/DOX cell line. Accumulation and release of DOX were examined in this cell line. The reversal effect was compared with that obtained with verapamil. S9788 activity was schedule dependent: when comparing incubation with S9788 before or after treatment with DOX, the best reversal factor was obtained in the case of a post-treatment incubation (65.6 +/- 7.7 vs 20.8 +/- 7.0). S9788 was a more potent modulating agent than verapamil, whatever the schedule of exposure of the cells to the reversal agent. The reversal of resistance after short-term DOX exposures was caused not only by prolonged cellular accumulation of DOX, but also by its prolonged retention after transfer of cells to DOX-free medium. A relationship was noted between cellular exposure to DOX and the cytotoxic effect, and so the reversal of resistance induced by S9788 appears to be directly linked to the level of cell exposure to DOX. This work provided a rationale for improving the schedule of administration of S9788 in clinical trials.

[Quantitative cytological study of the activity of a new resistance modulator, S 9788, on human leukemic cells using multiparametric image analysis]. / Etude cytologique quantitative de l'activité d'un nouvel agent modulateur de la résistance, le S 9788, sur des cellules leucémiques humaines par analyse d'image multiparamétrique.

The triazinoaminopiperidine derivative S 9788 is a new multidrug resistance modulator. The modulating activity of S 9788, comparatively to those of verapamil and the combination of S 9788 and verapamil, was demonstrated on the human leukemic T cell line CCRF-CEM resistant (about 6000 fold) to vinblastine using Microculture Tetrazolium Assay. S 9788 at 5 microM, strongly potentialized the cytotoxic activity of vinblastine but the reversion of resistance remained partial. Verapamil and the combination S 9788-verapamil, tested at equimolar concentrations, were respectively 1000 and two times less active than S 9788 alone. The impact of S 9788, verapamil and their combination on the cytological modifications bound to vinblastine resistance of CEM cells was evaluated by multiparametric quantitative cytological analysis (21 nuclear parameters measured) using a SAMBA 2005 cell image processor. Treatments with the different modulators, in absence or in presence of vinblastine, had no significant effects on the morphology of sensitive CEM cells. On vinblastine resistant CEM cells, S 9788 and the combination S 9788-verapamil induced significant cytological modifications. These modifications were characterized by a partial reversion of some parameters (more specifically nuclear texture parameters) to values close to those observed in parental sensitive cells and permitted an automatic classification of these treated resistant cells in cells of "sensitive" type with a percentage superior to 50%. In conclusion, the reversion of resistance induced by S 9788 on CEM cells resistant to vinblastine does not fit only with a biological phenomenon like the efflux of cytotoxic agents but is associated with a set of cellular alterations involved in multidrug resistance.

Follow up of soluble IL-2 receptor level in metastatic malignant melanoma patients treated by chemoimmunotherapy.

Immunological parameters following chemoimmunotherapy combination were studied in 31 patients with metastatic malignant melanoma. They received Cisplatin (100 mg/m2) on day 1 and 28, recombinant IL-2 (rIL-2; Eurocetus) in continuous infusion from day 3 to 6, 17 to 21, 31 to 34 and 45 to 49. Interferon-alpha (IFN-alpha; Roche) was given subcutaneously three times weekly. No significant change in CD4/CD8 ratio at onset or during treatment was observed between responder (n = 19) and non-responder (n = 12) patients. Regarding the IL-2 receptor (IL-2R) study, the percentage of cells expressing Tac (p55) receptor did not change either for healthy volunteers (n = 20) and patients before any therapy, or between responder and non-responder patients. Concerning serum soluble IL-2R shedding before therapy, we observed a significant increase (P = 0.001) in patients (79 +/- 40 pM) compared with healthy donors (30 +/- 15 pM), but no significant variation was seen between responder and non-responder patients. In contrast, during the treatment, the soluble IL-2R level increased in both groups but, interestingly, a significant difference was found between responder and non-responder patients from day 7 (P < 0.05) to day 21 (P < or = 0.01), suggesting that the cells from non-responder may be slower in becoming stimulated. This finding is the most striking point of our study and suggests that sIL-2R might be an early predictive factor of the clinical response as obtained by logistic regression (P = 0.0063). Therefore patients with a serum soluble IL-2R level greater than 250 pM at day 21 have a 12-fold more chance of undergoing a clinical response.

Fotemustine in the treatment of brain primary tumors and metastases.

Fotemustine is a new chloroethylnitrosourea characterized by the grafting of a phosphonoalanine group onto a nitrosourea radical. Clinical studies using fotemustine have been conducted in malignant glioma, brain metastasis of non-small cell lung cancer, and disseminated malignant melanoma. In recurrent malignant glioma, fotemustine has been used as a single agent: assessed by computed tomography scan, after 8 weeks, the objective response rate was 26.3% among 38 evaluable patients. Median duration of response was 33 weeks. The main toxicity was hematological (thrombocytopenia and leucopenia). A trial with high-dose fotemustine and autologous bone marrow rescue in newly diagnosed glioma was conducted in 26 patients, and 6 showed a partial response. The median overall survival was approximately 11 months. Myelosuppression was noted in all patients except 1, and other toxicity reported was central nervous system toxicity and epigastric pain. Combined with radiotherapy in 55 patients, a 29% response rate was observed, and this combination was well tolerated and easily manageable on an outpatient basis. Finally, fotemustine has been used intraarterially, with 10 objective responses observed among 26 evaluable patients. In brain metastases of non-small cell lung cancer, fotemustine proved to be active with a response rate of 16.7%. Combined with cisplatinum, fotemustine is still under study, but preliminary results are promising. In cerebral metastases of disseminated malignant melanoma, fotemustine has been evaluated in a total of 140 patients in the various studies: median response rate is 24.3%, ranging from 8.3% to 60.0%. Fotemustine appears to be a good candidate in the treatment of primary brain tumors and metastases.

Antitumor activity of the new vinca-alkaloid S 12363 alone or in combination with verapamil on a human multidrug resistant renal carcinoma xenograft.

We have established a model of human renal cell carcinoma, Kgg2, transplanted into athymic nude mice which expressed P-glycoprotein (P-gp) (detected by flow cytometry) and a high level of mRNA transcript of mdr1 gene (Northern blot analysis). We have evaluated the antitumor activity of a new highly potent vinca-alkaloid derivative, S 12363, in comparison with the activity of the reference compound vinblastine (VLB), when used alone or in combination with verapamil (VRP). The influence of the calcium influx blocker verapamil on the activity of the combination of S 12363 with adriamycin (ADR) was also determined. The results showed that S 12363 at a dose of 0.05 mg/kg/day, administered alone by intraperitoneal route daily on days 1 to 5, induced a tumoral regression of 50% during the first days after treatment. This effect was potentialized by simultaneous treatment with verapamil at 20 mg/kg/day for 5 days, leading to a long-term reduction of 70% of tumor growth. Vinblastine at a dose of 0.4 mg/kg/day administered alone or in combination with verapamil, using the same protocol, was less efficient. The association of S 12363 at 0.075 mg/kg/day (on days: 1-5, 11, 21 and 31), adriamycin at 2 mg/kg/day (on days: 11, 21 and 31) and verapamil at 20 mg/kg/day (on days: 0-5, 11, 21 and 31) induced an important reduction of tumor growth of 80% at the end of the experiment. In conclusion, the new vinca-alkaloid derivative S 12363 could present a therapeutic advantage over the reference compound vinblastine in the treatment of renal cell carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Tamoxifen enhances the cytotoxic effects of the nitrosourea fotemustine. Results on human melanoma cell lines.

Fotemustine (Fote) is a new amino acid-linked chloroethyl nitrosourea which has been shown to be useful in disseminated malignant melanoma. The aim of the present study was to analyse the cytotoxic effects resulting from the combination of anti-oestrogens and Fote on human melanoma cell lines. The anti-oestrogens tested were tamoxifen (TMX, 5 x 10(-7) mol/l and 5 x 10(-6) mol/l) and 4OH TMX (5 x 10(-8) mol/l and 5 x 10(-7) mol/l). As a preliminary step, a series of nine human melanoma cell lines was screened in order to identify and quantify the presence of oestradiol receptors (ER) in these cell lines. This led to the selection of an ER-positive (+) cell line. The drugs alone or in combination were then tested against CAL 1 ER (+) and CAL 7 ER (-) melanoma cell lines. Different sequences of drug combinations were tested using clinically compatible drug concentrations. For CAL 1 cells, there was a growth inhibitory effect induced by the anti-oestrogens given alone. Overall, the presence of the anti-oestrogens resulted in higher cytotoxic effects than when cells were exposed to Fote alone. The lowest IC50 Fote values as compared to Fote alone were generated by the sequences in which the anti-oestrogens were administered before Fote. Significantly, these associations with anti-oestrogens enabled the IC50 values of Fote to be reduced by up to 80%. Globally, TMX and 4OH TMX had similar synergistic effects. TMX and 4OH TMX had a modest influence on Fote cytotoxic effects against CAL 7 ER-negative cells. These data may be useful for optimal planning of future clinical trials for malignant melanoma using anti-oestrogens and nitrosoureas.

Phase II study of fotemustine as second-line treatment after failure of immunotherapy in metastatic renal cell carcinoma.

Sixteen patients who after prior systemic immunotherapy had progressing disease received fotemustine (100 mg/m2) i.v. on days 1, 8, and 15 followed by a 5-week rest period. In responding or stabilized patients, maintenance therapy consisted of 100 mg/m2 fotemustine given once every 3 weeks until progression on toxicity occurred. No objective response was observed. Four patients showed stable disease (median duration: 4 months; range: 3-19). The main toxicities were neutropenia (WHO grade 3 and 4: 27%) and thrombocytopenia (WHO grade 3 and 4: 27%). Fotemustine was administered on an outpatient basis and was generally well tolerated, but in our series of patients it had no antitumour activity in metastatic renal cell carcinoma after failure of immunotherapy.

Evaluation of the time-schedule dependency for the cytotoxic activity of the new vinca alkaloid derivative, S 12363 (vinfosiltine).

S 12363 is a new vinca alkaloid derivative obtained by appending an optically active alpha-aminophosphonate at the C23 position of 04-deacetyl vinblastine. The present study concerns four different human tumour cell lines, which represent the spectrum of vinca alkaloid clinical activity. The influence of time exposure on S 12363 growth inhibition was studied in vitro. Cells were exposed to the drug during the following exposure times: 5, 15, 30 min and 1, 3, 6, 12, 24, 48, 72, 144 h. The concentrations of S 12363 applied were between 1 x 10(-2) and 1 x 10(3) nmol/l. The cytotoxic effects were assessed by using the methyltetrazolium (MTT) semi-automated test. Considering the IC50 values in terms of concentration (C) x time (T), I (C x T)50, it was shown that for an equal growth inhibitory effect (50% of cell death) the increased exposure times required higher cumulative drug exposures. More precisely, only very long exposure (greater than 24 h) resulted in very high I (C x T)50. The drug exposure ratios which correspond to I (C x T)50 values for 144 h divided by the I (C x T)50 values for 0.25 h ranged between 2.8 and 18.3. If T and C had symmetrical effects on the final growth inhibition, the I (C x T)50 ratios should have been equal to one. For all cell lines investigated there were similar dose-response curves following two types of S12363 exposure: a single day exposure or three successive daily exposures, the total C x T values being the same in both experimental situations. The basic pharmacological information provided by the present study may encourage further clinical trials of this potentially interesting new vinca alkaloid.

Activity and unexpected lung toxicity of the sequential administration of two alkylating agents--dacarbazine and fotemustine--in patients with melanoma.

We report the results and discuss the toxicity of clinical trials based on a single concept: the decrease in O6alkyl DNA alkyltransferase (O6AT) resistance mechanism when a chloroethylating agent is used sequentially after a methylating agent. This decrease in O6AT being dose dependent, several increasing doses of dacarbazine (DTIC) have been tested (400 mg/m2 to 1000 mg/m2 every 4 weeks, 3-4 h before fotemustine (100 mg/m2 intravenously every 4 weeks). These results (mean overall response rate 27%) compared with reference regimes, demonstrate that DTIC is able to increase the alkylating power of fotemustine: same range of response rate with only half of the two drug doses compared to an alternated combination, high activity rate especially in lung metastases (10/42 complete responses + 13/42 partial responses), different pattern for haematotoxicity, and occurrence of a new side-effect: acute lung toxicity as adult respiratory distress syndrome (ARDS). This lung toxicity was totally unexpected since several hundreds of patients had been so far treated with fotemustine as single agent or in other combinations with DTIC without any case of acute or delayed lung toxicity. Prophylactic administration of corticoids was not effective and monitoring of the respiratory function was of no predictive value. Due to the additional depleting effects of DTIC on at least two main defence mechanisms--the O6AT system and cytosolic and/or nuclear glutathione--we suppose that the sequence is able to increase the alkylating power of fotemustine to an excessive extent and/or that the detoxication capacity of the cell against DTIC and/or fotemustine metabolites is overwhelmed. Other depletors of the O6AT activity which do not generate metabolites that compete for the same detoxication pathway as the chloroethylnitrosourea (CENU) metabolites should be tested.

Effects of a new triazinoaminopiperidine derivative on adriamycin accumulation and retention in cells displaying P-glycoprotein-mediated multidrug resistance.

A new triazinoaminopiperidine derivative, Servier 9788 (S9788), was investigated for its ability to increase Adriamycin (ADR) accumulation and retention in two rodent (P388/ADR and DC-3F/AD) and three human (KB-A1, K562/R and COLO 320DM) cell lines displaying the P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) phenotype. Depending on the cell line S9788 was shown to be two to five times more active and five to 15 times more potent than Verapamil (VRP) in increasing ADR accumulation in resistant cells. ADR retention in KB-A1 cells maintained in a concentration of 10 microM S9788 was twice that in VRP-treated cells, and similar to that measured in the untreated sensitive KB-3-1 cells. Although 5 microM S9788 and 50 microM VRP gave the same values of ADR uptake in KB-A1 cells, S9788 was shown to induce a greater ADR retention following cell wash and post-incubation in resistance modifier- and ADR-free medium. Taking into account that S9788 had no effects on ADR accumulation and retention in sensitive KB-3-1 cells, it can be suggested that S9788 inhibits specifically the P-gp dependent ADR efflux, and in a manner less reversible than that observed with VRP. Moreover, [3H]azidopine photolabeling of P-gp, in P388/ADR plasma membranes, was completely inhibited by 100 microM S9788. Although S9788, as VRP, had no effect on the cell cycle of P388 cells, 5 microM S9788 increased 700-fold the efficacy of ADR to block P388/ADR cells in the G2+M phase of the cell cycle. Together, these results show that the sensitization, by S9788, of cell lines resistant to ADR is mainly due to an increase in ADR accumulation and retention, leading to an increase in the number of resistant cells blocked in the G2+M phase.

Fotemustine: an overview of its clinical activity in disseminated malignant melanoma.

Fotemustine is a new chloronitrosourea which is active against disseminated malignant melanoma (DMM), and especially against cerebral metastases (CM). This efficacy has been widely demonstrated through many phase II studies. A multicentre trial of monotherapy was undertaken in 153 evaluable French patients. A response rate (RR) of 24.2% (25.0% RR in CM; 31.8% in non-visceral metastases (NVM) was obtained. Three other phase II studies confirmed these results with respective objective RR of 16.7%, 20.0% and 47.0% and RR in CM of 8.3%, 14.3% and 60.0%. Fotemustine has also been used in combination with dacarbazine (DTIC), in patients with DMM. The RR among 103 patients was 27.2% (26.3% in CM, 37.5% in NVM), confirming the activity of fotemustine. The two drugs have also been administered sequentially, in order to exploit their synergism in interfering with the O6 alkyltransferase. Impressive RR have been achieved, especially in patients with visceral metastases (VM) but at the expense of a pulmonary toxicity that does not arise with other treatment schedules and which precludes its use outside of strictly conducted clinical trials.

In vitro and in vivo circumvention of multidrug resistance by Servier 9788, a novel triazinoaminopiperidine derivative.

S 9788 is a novel triazinoaminopiperidine derivative which does not belong to any of the classes of compounds known to reverse multidrug resistance (MDR). S 9788 was far more potent than verapamil (VRP) in reversing resistance to adriamycin (ADR) in the ADR-selected murine leukaemia cell lines P388/ADR-1 and P388/ADR-10, and the human chronic myelogenous leukaemia K562/R. Fold reversion with S 9788 (5 microM) was, respectively, 3.5, 5.4 and 11.3 times greater than that with VRP (5 microM). S 9788 was also a more potent reversant of ADR resistance in the intrinsically resistant human colon adenocarcinoma COLO 320DM (2.3 fold), and of vincristine (VCR) resistance in the human MDR1 gene-transfected squamous lung carcinoma line S1/tMDR1 (5.6 fold). The activity of S 9788 depended on both the MDR cell line and the cytotoxic agent. S 9788 (50-100 mg/kg/d) administered IP once a day on days 1-4 resulted in a dose-dependent increase in the chemotherapeutic effect of VCR (0.25 mg/kg/d) in P388/VCR - bearing mice and ADR (4 mg/kg/d) in P388/ADR - bearing mice. Increases in antitumor activity were (% T/C) of +20-34% in the P388/ADR model and + 50-78% in the P388/VCR model with respect to cytotoxic agent treatment alone. S 9788 appeared to be devoid of toxicity at its effective doses. The mechanism of action of S 9788 is unknown but S 9788 (0.5-10 microM) induced a dose-dependent increase in ADR accumulation in KB-Al cells and compared to verapamil its effect was twice as active and approximately seven times more potent. We conclude that S 9788 is a novel agent capable of reversing MDR in vitro and in vivo, and whose pharmacological profile warrants its selection as a candidate drug for eventual assessment in the clinic.