Phase I study of amrubicin plus cisplatin and concurrent accelerated hyperfractionated thoracic radiotherapy for limited‐disease small cell lung cancer: protocol of ACIST study

Background Etoposide plus cisplatin (EP) combined with concurrent accelerated hyperfractionated thoracic radiotherapy (AHTRT) is the standard treatment strategy for unresectable limited‐disease (LD) small cell lung cancer (SCLC), which has remained unchanged for over two decades. Based on a previous study that confirmed the non‐inferiority of amrubicin (AMR) plus cisplatin (AP) when compared with EP for extensive‐disease (ED) SCLC, we have previously conducted a phase I study assessing AP with concurrent TRT (2 Gy/time, once daily, 50 Gy in total) for LD‐SCLC therapy. Our findings revealed that AP with concurrent TRT could prolong overall survival to 39.5 months with manageable toxicities. Therefore, we plan to conduct a phase I study to investigate and determine the effect of AP combined with AHTRT, recommended dose (RD), maximum tolerated dose (MTD), and dose‐limiting toxicity (DLT) of AP in patients with LD‐SCLC. Methods Treatment‐naive patients with LD‐SCLC, age between 20 and 75 years, who had a performance status of 0 or 1 and adequate organ functions will be enrolled. For chemotherapy, cisplatin 60 mg/m2/day (day 1) and AMR (day 1 to 3) will be administered with AHTRT (1.5 Gy/time, twice daily, 45 Gy in total). The initial AMR dose is set to 25 mg/m2/day. RD and MTD will be determined by evaluating toxicities. Discussion Based on our previous study, the initial dose of AMR 25 mg/m2 is expected to be tolerated and acceptable. Here, we aim to determine whether treatment with AP and concurrent AHTRT would be an optimal choice with manageable toxicities for LD‐SCLC. Schema of ACIST study; phase I study to evaluate the efficacy and toxicity of CDDP + AMR + AHTRT for the patients with LD‐SCLC.