A phase II study of ifosfamide in combination with etoposide and cisplatin in the treatment of extensive small cell lung cancer.

The combination of etoposide and cisplatin has become one of the standard treatments for small cell lung cancer. Ifosfamide, an analogue of cyclophosphamide, has demonstrated single-agent antitumor activity comparable with that of the most active agents used to treat small cell lung cancer. Because ifosfamide is relatively nonmyelosuppressive and its principal dose-limiting toxicity, urotoxicity, has largely been eliminated with the introduction of the uroprotective agent mesna, we undertook a phase II study of the combination of all three agents (etoposide/ifosfamide/cisplatin) in good-performance-status, extensive-disease patients 70 years of age or younger. Twenty-five patients (17 men and eight women; median age, 58 years) were treated with 75 mg/m2 etoposide, 20 mg/m2 cisplatin, and 1.0 g/m2/d ifosfamide administered intravenously for 5 days. Mesna (200 mg/m2) was given as a bolus prior to the first day of chemotherapy and then daily by continuous infusion (900 mg/m2 over 24 hours) between administrations of chemotherapy. Mesna was continued for 12 hours after the last dose of ifosfamide. Treatment cycles were planned every 4 weeks for four cycles. Due to severe toxicities in the first eight patients, subsequent patients received only 4 days of treatment (20% dose reduction). Of the 25 extensive-disease patients studied, 23 are evaluable for response. Seven (30%) achieved a complete response and 10 (43%) had a partial response (overall response rate, 73%). Five patients (22%) had stable disease (< 50% decrease and no evidence of disease progression for at least 4 weeks), and disease progressed in 1 patient (4%). The median survival time was 42 weeks (range, 2 to 160+ weeks). Granulocytopenia was dose-limiting: median granulocyte count was 0.486 x 10(9)/L, 21% of cycles had a granulocyte nadir below 0.2 x 10(9)/L, and four patients died of sepsis. Three patients required platelet transfusion and nine needed blood transfusion. Microscopic hematuria occurred in eight patients (11% of treatment cycles) but was reversible in all cases. A number of central nervous system symptoms were reported but could not be definitely attributed to ifosfamide/mesna. Gastrointestinal toxicity was generally mild, which is attributed to the use of an aggressive antiemetic program. The etoposide/ifosfamide/cisplatin regimen is active and produced a complete response rate of 30% in extensive small cell lung cancer; the duration of response and survival appears similar to that of other standard regimens. The 5-day schedule produced excessive toxicity in this patient population, necessitating a 20% dose reduction (by using a 4-day schedule). The method of administration required a minimum of 5 hospital days per cycle.(ABSTRACT TRUNCATED AT 400 WORDS)