1657P Pazopanib treatment outcome in advanced soft tissue sarcoma: Real-world data

Background Pazopanib is approved for use after the failure of chemotherapy for soft tissue sarcoma. We aimed to evaluate the clinical outcome and tolerability in a real-world setting. Methods Patients treated between June 2015 and August 2019 were reviewed. The response was assessed at 8 and 12 weeks using the Response Evaluation Criteria in Solid Tumors version 1.1. Survival analysis was performed using the Kaplan-Meier method. Toxicity was assessed using the Common Terminology Criteria v. 5.0. Results Forty-five patients (51% male) were identified; the median age at diagnosis was 28 years (IQR 23–45 years). The histology subtypes were 26.7% undifferentiated pleomorphic sarcoma (UPS), 15.6% synovial sarcoma (SS), 17% leiomyosarcoma, 8.9% alveolar soft part sarcoma, 8.9% fibrosarcoma, 6.7% epithelioid sarcoma, and 13.3% other types. The most common site for metastases was the lung (55.6%) and liver (13.3%). Pazopanib was used as the second-line and subsequent-line therapy in 46.7% and 53.3% of patients, respectively. At 8 weeks, the clinical benefits rate was 48.9% (7 partial response (PR), 15 stable diseases (SD)), and at 12 weeks, it was 35.5% (6 PR, 10 SD). The median duration of response was 7 months and 3 patients maintained a response more than 12 months; two UPS and 1 SS. The median progression-free survival (PFS) was 3 months (95% confidence interval (CI): 0.75–6.), and the median overall survival was 13 months (95% CI: 7–18.9). There was no statistical difference between using pazopanib as a second- or subsequent line therapy, 5 vs. 2.9 months (p = 0.44). Totally, 71% of patients were maintained on the full dose (800 mg) and led to discontinuation in 9.5% patients because of transaminitis, interstitial lung disease, or fatigue. The reported grade III/IV toxicities (9 patients) were hypertension, neutropenia, thrombocytopenia, anemia, diarrhea, and fatigue. The most common grade I and II toxicities were anemia 35.5%, hypothyroidism 35.1%, transaminitis 28.9%, thrombocytopenia 24.5%, neutropenia 22.2%, hypophosphatemia 21.6%, and hypertension 15.9%. Conclusions Pazopanib was found to be tolerable and effective with outcomes comparable to those reported in clinical trials. No difference in PFS was observed when used either as a second- or subsequent line therapy.