The US Food and Drug Administration (FDA) has approved Pimjetmi (pimicotinib) as a systemic treatment for adults with symptomatic tenosynovial giant cell tumor (TGCT) for which surgical resection may cause worsening functional limitation or severe morbidity.
TGCT is a rare condition characterized by the abnormal growth of tissue lining the joints and tendons throughout the body (synovium), resulting in a noncancerous tumor. There are two types of TGCT: the local or nodular form (where the tumor involves the tendons that support the joint, or in one area of the joint) and the diffuse form (where the entire lining of the joint is involved). Symptoms might include pain, limitation of movement, and locking of the joint. The knee is most commonly affected by this condition, though it can occur in other joints. The underlying cause of TGCT is unknown.
Pimicotinib is a once-daily oral colony stimulating factor-1 receptor (CSF-1R) inhibitor.
The approval is based on primary and longer-term results from the pivotal, global phase 3 MANEUVER clinical trial (NCT05804045). The study is a three-part, randomized, double-blind, placebo-controlled trial assessing the efficacy and safety of pimicotinib in patients with TGCT.
Treatment with pimicotinib demonstrated a statistically significant improvement in objective response rate (ORR) at week 25 as assessed by a blinded independent review committee (BIRC) based on RECIST v1.1 compared with placebo (56% versus 3% for placebo). Pimicotinib also demonstrated clinically meaningful and statistically significant improvements as compared to placebo across secondary endpoints relevant to patients’ daily lives, improving relative range of motion, physical functioning, and pain.
In the longer-term follow up (median 14.3 months for patients initially randomized to pimicotinib), the median duration of response was not reached. 77% of patients with response at 25 weeks maintained clinical benefit after an additional 12 months of follow up, demonstrating the durability of response.
Additionally, pimicotinib was well-tolerated, with no evidence of cholestatic hepatotoxicity or hair/skin hypopigmentation. During the randomized, double-blind treatment phase of the trial, treatment-emergent adverse events (TEAEs) leading to treatment discontinuation occurred in one patient treated with pimicotinib. TEAEs leading to dose reduction occurred in 7.9% of pimicotinib-treated patients.
For more information, visit https://www.emdserono.com/us-en/company/news/press-releases/fda-approves-pimjetmi-for-tgct-11-10-2026.html
To learn more about TGCT and other rare musculoskeletal conditions, visit https://checkrare.com/diseases/musculoskeletal-diseases/