Phase I study of amrubicin plus cisplatin and concurrent accelerated hyperfractionated thoracic radiotherapy for...

Etoposide plus cisplatin (EP) with concurrent accelerated hyperfractionated thoracic radiotherapy (AHTRT) remains the standard treatment for unresectable limited-stage (LS) small cell lung cancer (SCLC)) for over two decades. Our previous study demonstrated that amrubicin plus cisplatin (AP) with once-daily thoracic radiotherapy (50 Gy per 25 fractions) for LS-SCLC prolonged overall survival (OS) to 39.5 months with manageable toxicities. To enhance therapeutic efficacy, this study aimed to assess the feasibility of AP combined with AHTRT for LS-SCLC.

Treatment-naïve patients aged 20-75 years with LS-SCLC, performance status 0-1, and adequate organ function were enrolled. Chemotherapy consisted of cisplatin 60 mg/m²/day (day 1) and amrubicin (days 1-3), administered concurrently with AHTRT (1.5 Gy/time, twice daily, 45 Gy in total). The initial amrubicin dose was set to 25 mg/m² and increased to 35 mg/m² from the second cycle.

Nine patients were enrolled in this study. Dose-limiting toxicities included Grade 3 febrile neutropenia and Grade 3 hypokalemia. The recommended and maximum tolerated dose of amrubicin was 25 mg/m². The overall response rate was 100%, with both median progression-free survival and OS not reached. The 5-year OS rate was 64.8%.

AP combined with AHTRT from the first chemotherapy cycle was well tolerated at the recommended amrubicin dose of 25 mg/m². This regimen demonstrated promising efficacy and may represent a potential therapeutic option for LS-SCLC.