Olaratumab and doxorubicin for the treatment of metastatic soft tissue sarcoma: a retrospective case series

Abstract

Purpose Soft tissue sarcomas (STS) are a rare and heterogeneous tumor group with limited treatment options. This study aimed to evaluate the anti-tumor efficacy of olaratumab and doxorubicin in patients with advanced STS in front-line and salvage setting. Methods Patients with STS who received olaratumab and doxorubicin between October 2017 and August 2018 were retrospectively reviewed. Response rate, progression-free survival (PFS), and overall survival (OS) were analyzed according to histologic subtype, Eastern Cooperative OncologyGroup performance status, and number of prior chemotherapy regimens. Results A total of 26 patients were included in the analysis. The common histologic subtypes included undifferentiated/unclassified sarcoma (n=8), leiomyosarcoma (n=7), liposarcoma (n=3), and solitary fibrous tumor (n=2). Of 26 patients, 10 patients (38.4%) received more than two chemotherapy regimens before olaratumab and doxorubicin. At the time of analysis, 152 cycles of olaratumab had been administered (median, five cycles), and there was no treatment-related mortality. The disease control rate was 61.5% (n=16), and the overall response rate was 15.3% (partial response, n=4; complete response, n=0). Partial responses were achieved in one patient with solitary fibrous tumor, one with dedifferentiated liposarcoma, one with leiomyosarcoma, and one with pleomorphic rhabdomyosarcoma, all in salvage setting. With a median follow-up duration of 11.1 months (95% confidence interval [CI], 11.1 to 13.1 months), the median PFS was 4.1 months (95% CI, 2.1 to 6.1 months), and the median OS was not reached. Conclusion Olaratumab and doxorubicin demonstrated acceptable anti-tumor activity in Asian patients with sarcoma.

Keywords

• Doxorubicin
• Olaratumab
• Sarcoma