7045 Background: CP has shown activity in CDE resistant pts with ED SCLC (Groen JCO 1999). We performed a RCT comparing CDE and CP in chemonaïve pts with ED SCLC. Methods: Primary end point: progression free survival (PFS), secondary: objective response rate (ORR), survival and toxicity. The study is powered to detect improvement PFS from 5.7 months to 8.4 months (α= 0.05, β= 0.80). Eligibility criteria: ED SCLC, PS 0–2, measurable disease, normal bone marrow and organ reserve. February 1999 to September 2004 98 pts were randomised to iv Cyclophosphamide 1000 mg/m2 (d1), Doxorubicin 45 mg/m2 (d1), Etoposide 100 mg/m2 (d1–3) q 3 weeks x 5 (CDE group) and 99 to iv Carboplatin (AUC 7) (d1) and Paclitaxel 175 mg/m2 (d1) q 3 weeks x 5 (CP group). Results: Pts characteristics are balanced between both arms; 84% pts ECOG PS 0–1. 81% of pts have died. Median number courses both arms 5, 47% vs 44% of pts had dose reductions. No difference in PFS (141 vs 102 days, p=0.89) was observed. ORR CDE group 64%, CP group 67%, median survival CDE group 6.5 mo, CP group 6.7 mo (p=0.68). The only significant difference in toxicity was grade 4 leucopenia (CDE group 59% pts, CP group 9% pts; p<0.0001) leading to febrile neutropenia in 24% vs 7% pts (p=0008). Conclusion: Treatment with CP does not improve PFS over CDE in ED SCLC. Hematological toxicity is significantly lower in pts treated with CP. No significant financial relationships to disclose.