Camrelizumab Plus Apatinib in Advanced Unresectable Alveolar Soft Part Sarcoma and Undifferentiated Pleomorphic Sarcoma Patients: A Single-Center, Exploratory Case Series

Background: Certain histologic subtypes of advanced soft tissue sarcomas, including alveolar soft part sarcoma (ASPS) and undifferentiated pleomorphic sarcoma (UPS), lack standardized therapeutic options following anthracycline-based first-line therapy. This study was to investigate the efficacy and safety of camrelizumab plus apatinib in advanced unresectable ASPS or UPS. Methods: In this single-center, exploratory case series, patients with ASPS or UPS received a combination of camrelizumab and apatinib. The primary endpoint was the objective response rate (ORR), while the exploratory endpoints included progression-free survival (PFS), overall survival (OS), and safety. Results: The median follow-up period was 24.0 months, with an ORR of 88.9% (8/9). In the ASPS subgroup (n=7), neither the median PFS (mPFS) nor median OS (mOS) was reached, while the ORR was 100.0% (7/7). In the UPS subgroup (n=2), the mPFS was 7.5 months and the mOS was 9.5 months, with the ORR of 50.0% (1/2). One patient with ASPS died from immune-mediated myocarditis; all other adverse events (AEs) were grade 1-2 and manageable with symptomatic treatment. Conclusion: The combination therapy of camrelizumab and apatinib may provide benefits in clinical outcomes for ASPS, while the outcomes in UPS appears more variable, warranting further study. Close monitoring for AEs, especially fatal complications such as immune-mediated myocarditis, is essential. Registration: ClinicalTrials.gov (identifier: NCT04447274), registration date: 23-Jun-2020.