Relationships between carboplatin exposure and tumor response and toxicity in patients with ovarian cancer.

PURPOSE: The study was undertaken to define the relationship between tumor response and carboplatin area under the curve (AUC) in patients with ovarian cancer; to study the relationship between carboplatin AUC and myelosuppression in the same population; to establish the true impact of carboplatin AUC, prior therapy, and pretreatment platelet and WBC counts on toxicity; and to define an optimal carboplatin exposure for treating patients with ovarian cancer. METHODS: With the equation AUC = dose/(glomerular filtration rate [GFR]+25), carboplatin AUC (course 1) was calculated for 1,028 patients (450 previously untreated) who received single-agent carboplatin (40 to 1,000 mg/m2) for advanced ovarian cancer. GFR was measured (chromium-51-edathamil [51Cr-EDTA] or creatinine clearance) in all patients. RESULTS: Regression analysis showed that carboplatin AUC, prior treatment, and Eastern Cooperative Oncology Group grade performance status (PS) are predictors of tumor response, thrombocytopenia, and leukopenia. Pretreatment platelet and WBC counts are additional predictors of thrombocytopenia and leukopenia, respectively. Although the likelihood of tumor response increased with increasing carboplatin AUC, this relationship was nonlinear. In all patient subsets, the likelihood of complete response (CR) or overall response did not increase significantly above a carboplatin AUC of 5 to 7 mg/mL x minutes. At any given carboplatin AUC, thrombocytopenia occurred more frequently than leukopenia, although both approached 100% as carboplatin AUC increased. Both thrombocytopenia and leukopenia were more frequent in pretreated than in untreated patients regardless of pretreatment count. At any carboplatin AUC, the influence of PS on likelihood of response and toxicity was profound. CONCLUSION: Carboplatin dosing by AUC will lead to more predictable toxicity, and increasing carboplatin AUC above 5 to 7 mg/mL x minutes does not improve the likelihood of response but does increase myelotoxicity. Therefore, careful evaluation of high-dose carboplatin therapy in a prospective, randomized trial is needed before such treatment becomes accepted practice.

Randomized study of cyclophosphamide, doxorubicin, and vincristine versus etoposide and cisplatin versus alternation of these two regimens in extensive small-cell lung cancer: a phase III trial of the Southeastern Cancer Study Group.

PURPOSE: The trial was undertaken to determine (1) the relative efficacy/toxicity of two commonly used combination chemotherapy regimens in patients with extensive small-cell lung cancer (SCLC) and (2) whether the rapid alternation of these two regimens could provide superior therapeutic results compared with either regimen alone. PATIENTS AND METHODS: In this phase III trial, 437 eligible patients were stratified by performance status (PS) and sex and were randomly assigned to receive either 12 weeks of cisplatin and etoposide (EP); 18 weeks of cyclophosphamide, doxorubicin, and vincristine (CAV); or 18 weeks of alternation of these two regimens (CAV/EP). RESULTS: There were no significant differences in treatment outcome for EP, CAV, or CAV/EP in terms of response rate (61%, 51%, 59%, respectively), complete response rate (10%, 7%, 7%, respectively), or median survival (8.6 months, 8.3 months, 8.1 months, respectively), with a non-statistically significant trend toward a longer median time to progression with alternating therapy (4.3 months, 4.0 months, 5.2 months, respectively). Crossover second-line chemotherapy given at progression produced low response rates and short survival, regardless of the regimen used. Myelosuppression was the dose-limiting toxicity for all patients, although the pattern and severity differed among the treatment arms. CONCLUSIONS: The combination regimens EP and CAV can be considered equivalently effective induction therapies in extensive SCLC, and these two regimens are, to some degree, crossresistant. Alternating therapy provides no therapeutic advantage compared with the use of either of these regimens alone and should not be considered as standard treatment in this clinical setting.