Background: This study examined the efficacy/effectiveness of pazopanib and trabectedin in previously treated metastatic synovial sarcoma (mSS). Materials & methods: A literature search identified studies (2002-2019) reporting outcomes of pazopanib and trabectedin in previously treated mSS, including median overall survival (mOS) and overall response rate (ORR). A meta-analysis was conducted and sensitivity analyses examined outcomes by agent (pazopanib/trabectedin), study type (clinical trial [CT] or real-world [RW]) and sample size. Results: Sixteen studies were included (pazopanib: n = 7; trabectedin: n = 9). Pooled mOS was 10.4 months and was consistent across agents and in RW and CT (pazopanib: 10.3; trabectedin: 10.4; CT: 10.8; RW: 9.9). ORR results were more variable (pooled ORR: 14.7%). ORR was consistently higher for RW (17.7%) than for CT (9.5%) and for pazopanib (18.9%) compared with trabectedin (12.3%). Conclusion: Poor outcomes across agents and settings highlight a need for novel treatments with improved efficacy. This study serves as a benchmark for efficacy estimates in this rare disease.
Keywords: clinical trials; metastasis; outcomes research; real-world evidence; sarcoma; solid tumors.
Synovial sarcoma (SS) is a rare and aggressive type of soft tissue sarcoma. SS frequently spreads to other locations, referred to as metastatic SS (mSS) and is associated with a high death rate. Patients treated with first-line chemotherapy (1L setting), may need further lines of treatment (≥2L setting), which commonly involve the drugs pazopanib and trabectedin. This study assessed how well pazopanib and trabectedin work in people with ≥2L mSS, by examining both clinical trial (CT) and real-world (RW) studies. Overall, findings across 16 studies showed that mSS patients lived approximately 10 months after treatment with pazopanib or trabectedin in the ≥2L setting, and this was similar across both agents (10.3 months for pazopanib; 10.4 months for trabectedin) and between the CT (10.8 months) and the RW (9.9 months) settings. In terms of response to treatment, a higher percentage of people appeared to respond in RW settings (17.7%) than in CTs (9.5%), and to pazopanib (18.9%) compared with trabectedin (12.3%). These results show there is a need for better treatments for patients with previously treated mSS. These findings are useful benchmarks for the development of future treatment approaches for this rare disease.