Pazopanib in the real-world setting in soft tissue sarcomas: data from the Italian national registry.

Background: Pazopanib is part of the therapeutic armamentarium for the treatment of patients with advanced non-adipocytic soft tissue sarcomas (STS) who have received prior chemotherapy, but its optimal use in STS histologies is still left to be further defined.

Design And Methods: Data on STS patients treated with pazopanib in Italy have been prospectively collected from July 2013 to December 2019 through a drug monitoring registry managed by the Italian Medicines Agency (AIFA). This nationwide observational cohort study included patients with advanced STS who received pazopanib. Clinicians were mandatorily requested to fill in the AIFA monitoring registry in order to prescribe pazopanib. Patients were recorded on the basis of their clinical characteristics, histological subtype captured at the time of treatment start, and clinical outcome. Primary outcome was time to treatment discontinuation (TTD). Secondary outcomes recorded were frequency of dose reduction and time to first dose reduction.

Results: We analyzed data from 1964 sarcoma patients. The most represented histological subtypes were leiomyosarcoma (44.7%), undifferentiated sarcomas/not otherwise specified (11.5%), and synovial sarcoma (8.1%). Overall, the median TTD was 106 days. The variables significantly associated to shorter TTD were Eastern Cooperative Oncology Group performance status (1-2 versus 0), the number of previous lines of treatment (2-4 versus 0-1) and prescribed dose (200 mg or 400 mg versus 800 mg, all once daily). Among the most represented (>20 patients) histological subtypes, we also observed longer TTD in patients with histological diagnosis of malignant solitary fibrous tumor if compared with undifferentiated sarcoma not otherwise specified.

Conclusions: In this nationwide observational real-world study, the outcomes are similar to those reported in the pivotal trial (PALETTE study). Our study includes a significant number of patients with rare/ultra-rare sarcoma subtypes and underlines possible differences in treatment duration among these histologies.