Efficacy of low dose pazopanib in advanced soft tissue sarcoma (STS): Experience from a dedicated sarcoma medical oncology clinic in India.

Abstract

e22555 Background: The approved dose of pazopanib in advanced STS is 800 mg/day and is not weight based. After initial patients who couldn’t tolerate pazopanib we started pazopanib at lower doses escalating to higher doses. There is already preliminary data about low dose pazopanib in asian patients. Methods: We retrospectively analysed the prospectively kept data base of patients with advanced non adipocytic STS who were treated with pazopanib at AIIMS sarcoma medical oncology clinic between September 2015 and February 2019. After start of pazopanib we get CT scan done every 3 monthly as institutional protocol. Statistical analysis was done by SPSS 23. Results: There were total of 66 patients with median age 40 yrs (17 – 81)and majority were males who (60). ECOG Performance status (PS) was PS 1 in 63% and PS 2 in 23%. Most common diagnosis was synovial sarcoma (22%), leiomyosarcoma (18 %), angiosarcoma (9%), MPNST(8%) and others (43%). Most of the patients received pazopanib as second line (59%) and third line (31%). 90% of patients received dose of 400 mg and remaining 10% of the patients received 600 mg of dose (in which it could be escalated after 1 month). Median weight was 63kg and median height in our patients was 160cm while the median BSA was 1.6. Dose escalation was attempted, but was not feasible due to toxicities. Out of total 66 patients, 57 were available for response assessment. RECIST responses were complete response (CR) was present in 2.9%, partial response (PR) in 17% , stable disease (SD) in 28%. The median progression free survival (PFS) was 5 months and median overall survival was 18 months after a median duration of follow up of 20 months. Grade 3 and grade 4 toxicities were present in 31% of the patients. Grade 3 hand foot syndrome (HFS) was present in 12% of patients.4.5% had hypertension. Other grade 3 and 4 toxicities were oral mucositis (6%) , transaminitis (4%) Cardiomyopathy (3%) and cholestasis jaundice (1.5%) with bilirubin elevated to the level on 19.1 mg/dl. This resolved after stoppage of Pazopanib. Conclusions: Pazopanib at low doses in our series was as efficacious and with similar toxicity as previous literature The option of lower dose pazopanib needs to be explored in Asian population who have lower body weight.