Introduction/Background U-LMS is a rare entity, that needs to be referred to highly specialized sarcoma centers. Despite large number of genomic mutations in soft-tissue sarcomas no targeted-therapy is effective and systemic chemotherapy (CT) represents gold standard treatment of advanced U-LMS. The antiangiogenetic agent pazopanib is an oral multitargeted tirosine-kinase inhibitor; it demonstrated a benefit in Progression Free Survival (PFS) of 3 months in a phase III randomized PALETTE trial.

Methodology We retrospectively investigated outcomes of pazopanib in patients with metastatic U-LMS in a tertiary oncologic center in Italy. Endpoints included response rate, progression free survival (PFS) and safety.

Results From September 2013 to March 2023, 30 women with metastatic U-LMS received Pazopanib. Most patients (93%) had a good performance status (PS ECOG 0–1) and median age was 53 years old (38–72 years old). The most frequent site of metastases was lung (70%) and the median number of previous chemotherapy was 3 (range 2–5). All patients started Pazopanib at 800 mg daily; 23% of patients required dose reduction. The most common grade (G) 3 events were hepatic toxicities (HT), nausea and vomiting (7%). Two patients definitively interrupted due to drug-related toxicities: one for anasarca and one for HT. Disease control rate was 43%, with 19% of partial responses. We recorded 4 complicated responses: 1 pneumothorax, 1 intestinal perforation, 1 intestinal occlusion and 1 emoftoe due to pulmonary cavitation. In the overall population median PFS was 3 months ; in the responders subgroup was 7 (range 4–21). Four patients are still on treatment after a median period of 6 months.

Conclusion Unselected patients treated with Pazopanib in real life had a PFS and safety consistent with literature. Responder patients have a greater benefit from treatment with durable responses. However, clinicians must be careful during treatment due to the possibility of complicated response.

Disclosures No potential conflict of interest to report