Abstract 2622: Unmet needs in metastatic synovial sarcoma across EU-5 countries
Authors: Pokras Shibani , Patel Nashita , Margotto Luana , Mpima Sheila , Culver Ken , Reich Adam 
Published: July 2021

Objective: Real-world data on metastatic synovial sarcoma (mSS) are lacking in Europe as it is a rare sub-type of soft tissue sarcoma (STS). Prior studies have examined the overall STS population or focused on patients with mSS in single institutions. Our study objectives were to describe patient characteristics, burden of disease, treatment patterns, and outcomes associated with mSS in EU-5 countries (France, Germany, Italy, Spain, and the UK) across multiple institutions.

Methods: This was a cross-sectional retrospective cohort study conducted with oncologists who completed a structured survey based on patient charts. Sites were selected to be representative of hospital care settings in each country; physicians must have treated &gt;2 adult patients with SS from Aug 2018 to Nov 2019. Data was captured on patients with mSS (alive and deceased). The index date was defined as the date of mSS diagnosis.

Results: 71 oncologists reported on 296 patients with mSS. Median age at index was 54 y, 66% were men. Patients had a median of 4 metastatic sites, predominantly lung (78%). 76% of patients had metastatic disease at initial diagnosis. 39% of patients were unemployed, of whom 53% were unable to work due to mSS. 71% of patients starting first-line (1L), 53% starting second-line (2L), and 38% starting third-line or further (3L+) therapy had an ECOG score 0-1. At the time of data collection:

• 174 metastatic patients had received 1L therapy (37% of patients received doxorubicin and ifosfamide combinations, 27% doxorubicin monotherapy, 15% ifosfamide as monotherapy or combination therapy, and 21% received other treatments).

• 101 metastatic patients received 2L therapy (30% received trabectedin alone or in combination, 17% ifosfamide mono/combination therapy, 16% pazopanib alone or in combination, 14% doxorubicin mono/combination with ifosfamide, with 24% receiving other regimens).

• 21 metastatic patients received 3L+ therapy (29% received trabectedin alone or in combination, 24% ifosfamide alone or in combination including doxorubicin, 10% pazopanib alone or in combination, 5% received doxorubicin alone or in combination, the remaining 35% received other regimens).

Median overall survival (mOS) estimated from date of metastatic diagnosis was 22 months (670 days, 95% CI: 546, 947). mOS in the 2L and 3L assessed from the date of respective line of therapy initiation was 6 months (181 days, 95% CI: 158, 274) and 5 months (150 days, 95% CI: 135, NA).

Conclusions: To our knowledge, this is the first and largest real-world evidence study focused on patients with mSS in EU-5. In the 1L, treatment with doxorubicin alone or in combination with ifosfamide is predominant; for 2L trabectedin is most common; and in 3L there is no consensus treatment approach. The variation in treatments across all lines of therapy, the documented worsening of ECOG status, and poor clinical outcomes, highlights the continued unmet need in patients with mSS.

Funding: GlaxoSmithKline (212253)

Citation Format: Shibani Pokras, Nashita Patel, Luana Margotto, Sheila Mpima, Ken Culver, Adam Reich. Unmet needs in metastatic synovial sarcoma across EU-5 countries [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2622.