Pazopanib monotherapy in the treatment of pretreated, metastatic uterine sarcoma: a single-center retrospective study

Objective: In the treatment of metastatic soft tissue sarcoma (STS), pazopanib is considered a standard treatment after failure of chemotherapy. We retrospectively investigated outcomes of pazopanib in patients with metastatic uterine STS. Methods: A retrospective study was performed on 35 consecutive patients with uterine STS treated with oral pazopanib 800 mg daily as salvage therapy for metastatic disease between September 2013 and December 2015. Endpoints included response rate, survival, and safety. Results: Among 35 patients, 27 (77%) had a histologic diagnosis of leiomyosarcoma (LMS) and the median age was 57 years (range, 36-70). Median number of metastatic sites was one (range, 1-5) with lung as the most frequently involved site. Pazopanib was generally well-tolerated: the major hematologic toxicity was grade 1/2 anemia (14%). Among the non-hematologic toxicities, grade 1/2 stomatitis was most commonly observed (22%), followed by fatigue and hypertension. Objective response and stable disease were observed in 10 (29%) and 11 (31%) patients, respectively. However, most cases of clinical response were observed in patients with LMS: 33% for LMS, 20% for undifferentiated pleomorphic sarcoma, and 0% for endometrial stromal sarcoma. Median progression-free and overall survivals were 5.8 months (95% confidence interval [CI]=3.6-8.1) and 20.0 months (95% CI=11.6-28.4), respectively. Conclusion: In this "real-world" retrospective study, salvage therapy with pazopanib demonstrated clinically relevant efficacy and tolerability in unselected patients with uterine STS. Although it is encouraging that outcomes for Korean patients with uterine STS were similar to those reported in the phase III trial, the clinical benefit was limited to LMS.