The FDA has accepted and granted priority review to the new drug application (NDA) for vimseltinib, a colony-stimulating factor 1 receptor (CSF1R)-directed therapy, for the treatment of patients with tenosynovial giant cell tumor (TGCT). The FDA has assigned a Prescription Drug User Fee Act (PDUFA) goal date of February 17, 2025.
The NDA is supported by data from the phase 3 MOTION study, a randomized, double-blind, placebo-controlled trial, which evaluated treatment with vimseltinib vs placebo in patients with TGCT. The study enrolled patients at least 18 years of age with a confirmed diagnosis of symptomatic TGCT not amenable to surgery and no prior anti-CSF1/CSF1R therapy. Eligible patients were randomly assigned 2:1 to receive 30 mg of vimseltinib twice weekly or placebo for 24 weeks.
Efficacy of Vimseltinib
At the 2024 ASCO Annual Meeting, investigators shared that at week 25, patients treated with vimseltinib (n = 83) achieved a statistically significant and clinically meaningful overall response rate (ORR) of 40% (95% CI, 29%-51%; P < .0001) compared with 0% in patients treated with placebo (n = 40). Additional results from the trial indicated that the agent demonstrated robust and statistically significant antitumor activity by tumor volume score (TVS), with an ORR of 67% (95% CI, 56%-77%) vs 0% with placebo (P < .0001).
The median duration of response (DOR) with vimseltinib using RECIST 1.1 criteria was not reached (NR; range, 0.03+ to 11.7+ months) and the median DOR using TVS was also NR (range, 0.03+ to 13.9+ months).
Vimseltinib also demonstrated statistically significant and clinically meaningful improvements vs placebo across all key secondary end points. From baseline the agent led to improvements in active range of motion (18.4% vs 3.8%; difference, 14.6%; P = .0077), as well as PROMIS-Physical Function (mean change, 4.6 vs 1.3; difference, 3.3; P = .0007). Additionally, vimseltinib led to improvements in worst stiffness Numeric Rating Scale (mean change, –2.1 vs –0.3; difference, –1.8; P < .0001), EQ-Visual Analogue Scale (mean change, 13.5 vs 6.1; difference, 7.4; P = .0155), and Brief Pain Inventory (40% vs 9%; difference, 26%; P = .0056).
Safety Profile
Vimseltinib also demonstrated a manageable safety profile that was well tolerated. The most common treatment-emergent adverse effects (TEAEs) included periorbital edema (all grade, 45%; grade 3/4, 4%), fatigue (33%; 0%), face edema (31%; 1%), pruritus (29%; 2%), and headache (28%; 1%). Notably, there was no evidence of cholestatic hepatotoxicity, drug-associated liver injury, or hair/skin hypopigmentation.
TEAEs resulted in treatment discontinuation in 6% of patients who received vimseltinib.
About Tenosynovial Giant Cell Tumor (TGCT)
TGCT is a rare, non-malignant tumor that forms in or near joints due to overexpression of CSF1, leading to inflammation and tissue damage. Surgery is the primary treatment, but these tumors often recur, necessitating new therapeutic options. If untreated or if the tumor continually recurs, damage and degeneration may occur in the affected joint and surrounding tissues, which may cause significant disability. For a subset of patients who are not amenable to surgery, systemic treatment options are limited and a new therapeutic option for TGCT is needed.
Expert Commentary
R. Lor Randall, MD, FACS, noted that focusing on patient quality of life (QOL) is the most important aspect of the management of TGCTs and vimseltinib may offer a safe option with tolerable adverse effects (AEs). "It is exciting to see another agent coming," Randall said in an interview with OncLive. "Potential treatment with vimseltinib does require at least the duality of the surgeon and the medical oncologist, and preferably an entire treatment board that is making decisions if and when this drug becomes available."
