Paclitaxel (1-hour) and carboplatin (area under the concentration-time curve 7.5) in advanced non-small cell lung cancer: a phase II study of the Fox Chase Cancer Center and its network

Abstract

We previously reported a 62% response rate and 54% 1-year survival rate for paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) administered by 24-hour infusion in combination with fixed-dose carboplatin to treat patients with advanced non-small cell lung cancer (NSCLC). Myelosuppression proved dose limiting, but was substantially reduced by the routine use of granulocyte colony-stimulating factor during the second and subsequent cycles. Activity for paclitaxel 135 mg/m2 and 200 mg/m2 by 1-hour infusion every 3 weeks in patients with NSCLC, with minimal myelosuppression and the suggestion of a dose-response relationship, has been reported. In November 1994, we initiated a phase II trial in patients with advanced, measurable, chemotherapy-naive NSCLC using paclitaxel 175 mg/m2 given in 1 hour, and carboplatin dosed to a fixed target area under the concentration-time curve of 7.5 every 3 weeks. In the absence of grade 4 myelosuppression, paclitaxel was escalated on an intrapatient basis by 35 mg/m2 per cycle to a maximum dose of 280 mg/m2 by cycle 4. Granulocyte colony-stimulating factor was not routinely used. Of the 57 patients accrued, 44 (81%) are Eastern Cooperative Oncology Group performance status 1. The median patient age is 64 years. To date, 54 patients are fully evaluable for toxicity. In the first 20 evaluable patients accrued (cohort A), myelosuppression was tolerable, but cumulative peripheral sensory neuropathy proved dose limiting: grade > or = 1 in 15 (75%) patients and grade 3 in six (30%), generally occurring at paclitaxel doses > or = 215 mg/m2 and obligating at least three patients to be removed from study despite absence of disease progression. The protocol was consequently revised. The starting dose of paclitaxel was reduced to 135 mg/m2 with intrapatient dose escalations of 40 mg/m2 per cycle, to a maximum paclitaxel dose of 215 mg/m2, recapitulating the original dosing schema used in Fox Chase Cancer Center study 93-024. For the 35 patients enrolled in the second cohort (cohort B), treatment has been better tolerated. Of 21 evaluable patients, 13 (62%) have experienced peripheral sensory neuropathy, grade 3 in only one (5%) patient. Myelosuppression also has been less pronounced, with 44% grade 4 granulocytopenia and 38% grade > or =3 thrombocytopenia in cohort B compared with 70% and 50%, respectively, in cohort A. Of the first 22 patients accrued to cohort A, 12 (55%) had major objective responses. Median event-free survival is 24 weeks and median survival is 47 weeks. Of the 35 evaluable patients in cohort B, nine (26%) have had major objective responses. Median event-free survival is 22 weeks. It is too early to report median survival. Paclitaxel given by 1-hour infusion in combination with carboplatin at a fixed target area under the concentration-time curve of 7.5, although active in advanced NSCLC, is associated with problems that compromise its efficacy. Higher dose levels yield intolerable toxicity, evidenced by the incidence of neurotoxicity (rather than myelosuppression) that was dose and protocol limiting at paclitaxel doses exceeding 215 mg/m2. Lower doses, while more tolerable, appear to be associated with lower response rates.