Patient-Reported Continued Benefits in Patients Treated with Pexidartinib for Tenosynovial Giant Cell Tumor Based on a Real-World Study in the United States

Category: Other Introduction/Purpose: Tenosynovial giant cell tumors (TGCT) are neoplastic, inflammatory lesions that arise within the synovium and can be locally aggressive. Patients with TGCT frequently experience pain and joint swelling, stiffness, reduced range of motion, and instability in affected joints. Surgical resection is standard treatment for TGCT; however, the diffuse subtype is associated with poor surgical outcomes and high rates of disease recurrence. Pexidartinib (Turalio ® ), a CSF-1R antagonist, is the first and only systemic therapy approved by the FDA for treatment of adult patients with symptomatic TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. The objective of this study was to assess symptom change over time among adult patients who were treated with pexidartinib for TGCT in a real-world setting. Methods: This was a longitudinal observational study of patients receiving pexidartinib for TGCT treatment in the real-world setting. The study collected Patient Reported Outcomes (PRO) from patient surveys prospectively and clinical data from medical charts retrospectively. The surveys were administered to adult patients enrolled in the post-market Turalio ® Risk Evaluation and Mitigation Strategy (REMS) program: the first wave was sent in 2021 (“Baseline”) and the final was sent in 2022 (“Follow-up”). Patients were required to be receiving pexidartinib before the Baseline Survey and to be on pexidartinib when they accessed the Follow-up Survey. The surveys consisted of validated instruments to measure PROs. The EQ-5D-5L was administered in the Follow-up Survey to understand patients’ general health state. The scores and paired changes from baseline were summarized by descriptive statistics and a random slope regression model was developed to adjust for the time since first pexidartinib dose. Results: Forty-five patients actively taking pexidartinib to treat TGCT were invited to participate in both waves of the survey; 31 (68.9%) participated in both surveys. Mean (SD) time between baseline and follow-up was 1.02 (0.17) years, mean (SD) age at follow-up was 41.9 (13.70) years, and 67.7% were female. The most common tumor sites were at the knee (67.7%), ankle (16.1%), foot (9.7%), and hip (9.7%) (non-mutually exclusive). Changes in PROs are shown in Table 1. During follow-up, at least 71% of respondents indicated slight or no problems in each of the five EQ-5D-5L domains. Since the start of the study, the majority (85.7%) of respondents experienced improved overall symptoms. Conclusion: In this study, most TGCT patients reported symptom improvement in physical function, stiffness and pain during pexidartinib treatment. After an additional year of follow-up, the PROs of physical function, worst stiffness, worst pain, and treatment satisfaction were sustained. The findings suggest longer-term benefits for patients continuing treatment with pexidartinib. Outcomes for patients who discontinued pexidartinib should be evaluated in future studies.