Real-world experience with doxorubicin and olaratumab in soft tissue sarcomas in England and Northern Ireland.

Background: A randomised phase II trial demonstrated that the addition of olaratumab to doxorubicin significantly increased overall survival (OS) in patients with advanced soft tissue sarcomas (STS) compared to doxorubicin alone. The recently presented phase III study of doxorubicin and olaratumab in advanced soft tissue sarcoma was discordant with this finding.

Methods: We performed a retrospective analysis of adult patients with advanced-/metastatic STS treated with at least two cycles of doxorubicin and olaratumab at eight sarcoma units across England and Northern Ireland between May 2017 and March 2019.

Results: 172 patients were evaluable and 40 patients (23.3%) had died at the time of analysis. Median ECOG performance status (PS) was 1. Median progression free survival (PFS) was 6.8 months (95% CI 5.9-7.7 months). Leiomyosarcoma was the most common histological subtype (75 patients, 43.6%), followed by liposarcomas (19, 11.0%). The mean number of cycles was 5 (doxorubicin range 2-6; olaratumab range 2-23). Two patients (1.2%) had a complete response and 34 (19.8%) had a partial response. 79 (45.9%) had stable and 58 (33.7%) progressive disease. 57 patients (33.1%) experienced grade ≥ 3 neutropenia and 7 patients (4.1%) grade ≥ 3 febrile neutropenia. Grade ≥ 3 anaemia was seen in 21 patients (12.2%). Grade ≥ 3 non-haematological toxicities were seen in 35 patients (20.3%). A clinically significant drop in left ventricular ejection fraction was seen in 6 patients (3.5%). 48 patients (27.9%) required a dose reduction. Overall survival (OS) is pending.

Conclusions: Our results are in keeping with the phase III study findings: response rate, PFS and OS were similar to those reported in the phase III ANNOUNCE trial.