Olaratumab plus anthracyline in advanced/metastatic soft tissue sarcoma

Olaratumab is a humanized monoclonal antiplatelet-derived growth factor receptor alpha antibody that has been approved in combination with doxorubicin for the treatment of patients with metastatic soft tissue sarcoma (STS). The purpose of this retrospective study was to assess the clinical efficacy in STS patients treated with olaratumab in a real-world setting in Austria.

Retrospectively collected longitudinal data from patients treated between November 2016 and September 2018 at 9 Austrian centers were obtained from the respective medical charts. All patients who received at least one dose of olaratumab were eligible. Parameters of most interest were response rates, progression-free survival (PFS) and overall survival (OS).

Altogether 55 patients were included in the analysis. The median age was 58 years. In total, 65.5% (n = 36), 21.8% (n = 12) and 12.7% (n = 7) received olaratumab as first, second or ≥third line treatment, respectively. Olaratumab was administered either in combination with doxorubicin (81.8%, n = 45) or liposomal doxorubicin (16.4%, n = 9); one patient received olaratumab as upfront monotherapy. The median PFS and OS were 2.6 and 11.4 months, respectively. The objective response rate was 11.4% and the disease control rate was 40.9%.

In this real-world analysis the outcome was less pronounced compared to the results of both the phase Ib/II approval trial and the confirmatory phase III trial. The latter failed to show an improvement in OS and PFS for the doxorubicin/olaratumab combination. As such, olaratumab should not be used anymore in patients with STS.