Pasireotide as Maintenance Treatment in Synovial Sarcoma and Desmoplastic Small Round Cell Tumor — PAMSARC  

Synovial Sarcoma Clinical Trial

Official title: Pasireotide as Maintenance Treatment With Monthly Deep Intramuscular Injection in SSTR2/3/5-Expressing Synovial Sarcoma and Desmoplastic Small Round Cell Tumor

Status Not yet recruiting

Clinical Trial Summary

PAMSARC is a non-commercial interventional Phase 2 clinical trial of academic research institutions, with its primary goal being to improve medical treatment of fusion driven Desmoplastic small round cell tumor (DSRCT) and Synovial sarcoma (SySa) in young adults and adolsecents with male predominance.

Current management of DSRCT and SySa includes chemotherapy, radiation and aggressive cytoreductive surgery. Despite advances in multimodal therapy, outcomes remain poor with frequent disease recurrence and very limited options for patients with advanced disease.

Selected somatostatin receptor (SSTR) family members, i.e., SSTR2, SSTR3 and SSTR5, are frequently overexpressed in DSRCT and SySa, providing the rationale for treatment with somatostatin analogues (SSA).

Pasireotide is a SSA with high affinity for SSTR1, -2, -3, and -5 and is approved for the treatment of Cushing's disease and acromegaly and has also shown activity in other cancers. In patients with advanced stage DSRCT and SySa, conventional chemotherapeutic approaches frequently lead to disease response, however, the duration of progression-free time after chemotherapy is short. The targeted approach with pasireotide after initial intensive multimodal treatment may have the potential to significantly improve outcome.

Clinical Trial Description

Desmoplastic small round cell tumor (DSRCT) is an extremely rare, aggressive sarcoma. It originates from the serosal surface of the abdominal cavity and the hallmark characteristic of DSRCT is the EWSR1-WT1 gene fusion. Synovial sarcoma (SySa) is also a rare fusion-gene driven (SS18-SSX1, SS18-SSX2, or rarely, SS18-SSX4) soft-tissue sarcoma.

Selected somatostatin receptor (SSTR) family members, i.e., SSTR2, SSTR3 and SSTR5, were highly expressed in patients with available transcriptome data, providing the basis for treatment with a somatostatin analog such as pasireotide with high affinity for SSTR1, 2, 3, and 5.

The primary aim of the study is to assess the clinical efficacy of pasireotide maintenance therapy for prolonging progression-free (PFS) and overall survival (OS) in patients with SSTR2/3/5-expressing advanced SySa and DSRCT. Furthermore measurable residual disease (MRD) before, during, and after pasireotide maintenance therapy are assessed. Pasireotide is applied in adults with 60 mg and in adolescents 60 mg (body surface area [BSA] >1.6 m²) or 40 mg (BSA 1.1-1.6 m²) via intragluteal via intragluteal depot injection every 28±3 days. The sample size is planned for the entire study population with subsequent sensitivity analysis in two subgroups, i.e., adolescents and adults. The primary efficacy analysis is be based on a two-sided, one-sample log-rank test using a significance level of 5%. The sample size was calculated assuming exponential data, planning for a power of 90% to detect a hazard ratio of 0.5. With a sample size of n=28, the expected number of events during the study is 22. Safety is assessed continuously according to CTCAE v5.0. The recruitment period is planned for 2 years starting in 2024 followed by a minimal follow-up of the last patient of 6 months leading to estimated trial completion in 2027. ;

Related Conditions & MeSH terms

• Desmoplastic Small Round Cell Tumor
• Sarcoma
• Sarcoma, Synovial
• Synovial Sarcoma

• NCT number: NCT06456359
• Study type: Interventional
• Source: University Hospital Heidelberg
• Contact: Richard F. Schlenk, Prof.
• Phone: +49 (0)6221 56 6228
• Email: richard.schlenk@nct-heidelberg.de
• Status: Not yet recruiting
• Phase: Phase 2
• Start date: September 2024
• Completion date: October 2028