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The purpose of this systematic study was to provide an up to date and reliable quantitative summary of the relative benefits of various types of chemotherapy (non-platinum vs platinum, single-agent vs combination and carboplatin vs cisplatin) in the treatment of advanced ovarian cancer. Also, to investigate whether well-defined patient subgroups benefit more or less from cisplatin- or carboplatin-based therapy. Meta-analyses were based on updated individual patient data from all available randomized controlled trials (published and unpublished), including 37 trials, 5667 patients and 4664 deaths. The results suggest that platinum-based chemotherapy is better than non-platinum therapy, show a trend in favour of platinum combinations over single-agent platinum, and suggest that cisplatin and carboplatin are equally effective. There is no good evidence that cisplatin is more or less effective than carboplatin in any particular subgroup of patients.

As of June 1998, four randomized trials have been completed comparing the combination of paclitaxel and cisplatin with a cisplatin-based control arm. The results of three of these trials are available; one has been published as a full paper, the other two in abstract form only. Two of the reported trials (GOG-111 and the Intergroup trial) provide clear evidence that cisplatin combined with paclitaxel is a more effective regimen than one using the same dose of cisplatin combined with cyclophosphamide. The results of the third reported trial (GOG-132) are rather different, suggesting that a higher dose of single-agent cisplatin may be as effective as the paclitaxel/cisplatin combination tested in the other two trials. A number of explanations for these unexpected results have been proposed: false-positive results in GOG-111 and the Intergroup trial; false-negative results in GOG-132; high crossover in GOG-132 (including crossover before progression); the cyclophosphamide in the control arm of GOG-111 and the Intergroup trial had a negative impact on outcome in the control group in these trials; the higher dose of cisplatin when used as a single agent in GOG-132 had a positive impact on outcome for the control group in this trial. These explanations are discussed in detail, and their implications explored.

To determine if chemotherapy dose intensity influences treatment outcome in advanced ovarian cancer, all randomised studies of first line chemotherapy, published between 1975 and 1989, were analysed for relationships between planned dose intensity and (a) objective response and (b) median survival. Total dose intensity of each study regimen was calculated and a weighted regression model providing for systemic differences in response or survival among studies was utilised. Hence, treatment arms of different studies were never directly compared. In addition, relative dose intensities of individual drugs within combinations was similarly evaluated. The improvement in objective response rate when adding one unit of total dose intensity ranged between 12% and 16% depending on baseline response rate. The improvement in median survival when adding one unit of total dose intensity ranged between 2 and 4 months. One unit of total dose intensity corresponds to, for example, 20 mg m2 week of cisplatin, or 25 mg m2 week of doxorubicin, or 350 mg m2 week of cyclophosphamide. The analysis of individual drugs suggested that doxorubicin and the platinum compounds were about equally effective, with cyclophosphamide being less effective. The methodological benefits and limitations of the approach used and the implication of the results are discussed.

The data on 914 patients enrolled in four randomised trials in advanced ovarian cancer, consecutively conducted by the same cooperative group between 1978 and 1986, were analysed with the aims of: (1) determining the impact of selected prognostic variables on survival; (2) finding, from the interaction of favourable prognostic factors and treatment, an approximate estimate of the magnitude of the survival advantage associated with the use of platinum-based combination chemotherapy. The overall 3-year survival in this series of patients is twice that reported historically (22%; 95% CL 18.7-25.4). The proportional hazard regression model was used to perform the analysis on survival. Residual tumour size, age, FIGO stage and cell type were all independent determinants of survival. Differences in survival from the various prognostic groups were impressive with 5-year survival rates ranging from 7 to 62%. However, these differences were not qualitative (i.e. the kinetics of survival were similar for the best and the worst groups) suggesting that current prognostic factors are of little use for selecting 'biologically' different sub-populations. Platinum-based regimens were associated to an overall prolonged median survival, but this benefit was not observable in the subgroup with most favourable prognosis (less than 2 cm residual tumour size). The implications of these observations for clinical research and ovarian cancer patients care are discussed.

A total of 155 samples from 101 patients with ovarian cancer were investigated using flow cytometry to evaluate the DNA index and the percentage of cells in the various cell cycle phases. Thirty-four samples were DNA diploid tumours, while the other 121 were DNA aneuploid tumours. The DNA index was very stable in different sites and over time in the same patient. Tumour stage and ploidy were significantly associated: stages III and IV tumour stage were more likely to be DNA aneuploid. Patients with residual tumour size at first surgery greater than 2 cm had a significantly larger number of DNA aneuploid than DNA diploid tumours. The DNA index was also related to the degree of differentiation of the tumours. The percentage of cells in the S phase of the cell cycle was significantly higher in DNA aneuploid and in poorly differentiated tumours than DNA diploid and well differentiated tumours. Multivariate analysis using the Cox model showed that the DNA index and the percentage of cells in S phase were not independent prognostic variables in this study. Prospectively collected data should be accumulated before assigning the DNA index an important role as a biological prognostic factor in ovarian cancer.

We evaluated the myelotoxicity and the anti-tumor potential of tallimustine, three of its analogues and carzelesin, with melphalan as reference substance. Tallimustine was tested by clonogenic assays on both human bone marrow (BM) and cord blood (hCB) cells, the other compounds on hCB only. The degree of inhibition of the haemopoietic progenitors GM-CFC, CFC-E and BFU-E was evaluated after exposure to different concentrations. The same schedules were tested on five tumour cell lines. We found that the dose-response curves for tallimustine on BM and hCB cells were similar. Carzelesin was shown to be the most potent of the substances tested and to be the one with the best in vitro therapeutic index; of the distamycin analogues, the one bearing an alpha-bromoacrylic group (FCE 25450) had the best index. For melphalan, tallimustine and carzelesin, the concentration inhibiting the growth of 70% of progenitor cells in vitro (ID70) was similar to the concentrations found in the serum of patients treated at the maximum tolerated dose (MTD). We conclude that hCB cells may be used instead of BM cells for in vitro myelotoxicity tests. Therapeutic indexes can be extrapolated from this model and could help in selecting the most promising analogue for further clinical development. The in vitro-active concentrations are similar to myelotoxic concentrations in patients, suggesting a predictive value for the assay.