Phase II trial of recombinant IFN-α2a with etoposide/cisplatin induction and interferon/megestrol acetate maintenance in extensive small cell lung cancer

Previous data suggested interaction of cisplatin with interferon (IFN) in non-small cell lung cancer and a possible effect of IFN in maintaining remission in small cell lung cancer (SCLC). This study was designed to further examine the effect of IFN in the treatment of extensive disease (ED) SCLC. Forty previously untreated patients with performance status (PS) of 0- 2 (Zubrod scale) were treated with etoposide (100 mg/m² for 3 days), cisplatin (25 mg/m² for 3 days) (EP), and recombinant IFN-α2a (rIFN-α2a) (5 x 10⁶ U/m² for 3 days) for six cycles (induction), followed by rIFN- α2a (5 x 10⁶ U/m²) thrice weekly and megestrol acetate (40 mg qid) as maintenance therapy for 6 months or until progressive disease or intolerable toxicity was documented. Patients were 25 men (62%) and 15 women (38%), median age 58 (28-76), median Zubrod performance status 1 (0-2). Major sites of metastasis include liver (55%), bone (42%), bone marrow (25%), and adrenal gland (18%). Of 40 eligible patients accrued to this trial, 35 were evaluable for response, and 37 were evaluable for toxicity. There were 3 complete and 28 partial responses, for an overall response rate of 89%. With 39 of 40 patients followed until death, median survival (Kaplan-Meier) is estimated at 46 weeks (95% CI range 35-55). Twenty patients completed six cycles of induction, and 16 received maintenance therapy, median 2 cycles (range 1-3). Major toxicity during induction included grade 4 granulocytopenia in 24%, grade 2-3 nausea or vomiting or both in 41%, grade 2 fatigue in 24%, grade 2 anorexia in 22%, and grade 2-3 renal insufficiency in 9% of 175 total courses of chemotherapy administered. Toxicity during the maintenance phase was notable for grade 2-3 fatigue in 43%, grade 2-3 anorexia in 24%, grade 2-3 weight loss in 10%, and grade 3-4 anemia in 17% of 30 courses. There were no treatment-related deaths. The addition of rIFN-α2a to EP in induction chemotherapy of ED SCLC, followed by rIFN-α2a and megestrol acetate maintenance therapy, was reasonably well tolerated. The complete and overall response rates and duration of remission and survival appear to be similar to those generally obtained with EP alone in similar patients.