Outcome of uterine sarcoma patients treated with pazopanib: A retrospective analysis based on two European -rganisation for Research and Truatment of Cancer (EORTC) Soft Tissue and Bone Sarcoma Group (STBSG) clinical trials 62043 and 62072

Background Uterine sarcomas are a group of mesenchymal tumours comprising several histologies. They have a high recurrence rate following surgery, modest outcome to systemic therapy, and poor overall survival. Pazopanib is a multi-targeted tyrosine kinase inhibitor approved for non-adipocytic advanced soft tissue sarcomas (STS). Here we investigated whether response to pazopanib in patients with uterine sarcomas differs from that of patients with non-uterine sarcomas. Patients and methods Uterine sarcoma patients were retrieved from all soft tissue sarcoma patients treated with pazopanib in EORTC Phase II (n = 10) and Phase III (PALETTE) (n = 34) studies. Patient and tumour characteristics, response, progression free and overall survival data were compared. Results Forty-four patients with uterine sarcoma were treated with pazopanib. The majority of patients had uterine leiomyosarcoma (LMS) (n = 39, 88.6%) with high grade tumours (n = 37, 84.1%) compared to 54.8% (n = 164) in the non-uterine population. The median age was 55 years (range 33-79) and median follow up was 2.3 years. Uterine patients were heavily pre-treated, 61.3% having ≥ 2 lines of chemotherapy prior to pazopanib compared to 40.8% in the non-uterine population. Five patients (11%), all LMS, had a partial response (95% CI 3.8-24.6). Median progression free survival (PFS) 3.0 months (95% CI 2.5-4.7) in uterine versus 4.5 (95% CI 3.7-5.1) in non-uterine STS. Median overall survival (OS) was 17.5 months (95% CI 11.1-19.6), longer than the non-uterine population, 11.1 months (95% CI 10.2-12.0) (p = 0.352). Conclusions Despite heavy pre-treatment, pazopanib shows signs of activity in patients with uterine sarcoma with the similar outcomes to patients with non-uterine STS.