New Data Support Pimicotinib as Durable for Rare Tenosynovial Giant Cell Tumor

Research presented at the 2026 annual meeting of the American Society of Clinical Oncology (ASCO) add to the growing evidence base for pimicotinib, an oral colony-stimulating factor-1 receptor (CSF-1R) inhibitor, in patients with tenosynovial giant cell tumor (TGCT).

TGCT is a locally aggressive neoplasm arising from the synovial tissue of joints, tendon sheaths, and bursae. Although the tumors grow in soft tissue, which is the anatomical territory most associated with sarcomas, TGCTs are histologically benign. They do not metastasize, and the distinction matters clinically as patients are dealing with a chronic, debilitating condition rather than a life-threatening malignancy. Still, for the subset with diffuse or unresectable disease, the morbidity can be profound. Persistent pain, swelling, and loss of joint mobility are common, and surgical options are limited by high recurrence rates. The development of CSF-1R inhibitors like pimicotinib offers a targeted approach to interrupting the CSF-1 overproduction that drives the tumor's growth and inflammatory recruitment.

Tumor Response Holds Across Joint Locations 

Research led by investigators at The Ohio State University Comprehensive Cancer Center and MD Anderson Cancer Center examined whether pimicotinib's efficacy in the global phase 3 MANEUVER trial (NCT05804045) varied by tumor location, a clinically relevant question given that TGCT can affect joints throughout the body with differing functional consequences.¹

Among 63 patients randomized to pimicotinib 50 mg once daily, the majority had diffuse TGCT (84.1%) involving the lower extremity (85.7%), with the knee being the most common site (52.4%). Objective response rates (ORR) by blinded independent review per RECIST v1.1 were consistent regardless of tumor subtype, with data showing 87.5% for localized and 75.5% for diffuse disease. Responses were similarly comparable for lower vs upper extremity tumors (75.9% vs 77.8%) and knee vs other locations (75.8% vs 76.7%).

Functional outcomes reinforced the clinical meaningfulness of these responses. Knee range of motion improved by a mean of 8.9 degrees from baseline to week 49. Patient-reported physical function scores on the PROMIS-PF instrument, which covered walking, stair climbing, standing, and bending, showed consistent gains across all domains, with most patients moving from "with some difficulty" toward "with a little difficulty" or better.

Long-Term Safety Profile Remains Manageable

Further research reported on the longer-term tolerability of pimicotinib as well as the management of adverse events (AEs), providing both trial-specific and integrated data across the phase 1 and phase 3 programs from the MANEUVER trial.

Researchers pooled safety data from 158 patients treated with pimicotinib 50 mg once daily across the phase 1 and 3 MANEUVER trials, with a median exposure of 385.5 days.² Nearly all patients (99.4%) experienced at least 1 treatment-emergent AE (TEAE), but the severity profile was largely favorable as most patients had a maximum grade of 1 or 2. The most frequently reported AEs included creatine phosphokinase (CPK) elevation (72.2%), aminotransferase elevation (59.5%), edema (54.4%), rash (46.2%), and pruritus (43.0%). Fatigue was reported in 20.9% of patients. Importantly, no cases of cholestatic hepatotoxicity or drug-induced liver injury were identified. Treatment discontinuation due to AEs was rare, occurring in 5.1% of patients, and no drug-related deaths were reported.

Another research poster focused specifically on AE management strategies within the MANEUVER trial cohort after at least 1 year of treatment.³ Among 63 patients who received pimicotinib, TEAEs of at least grade 3 occurred in 46%, driven primarily by elevated CPK (15.9%) and rash (6.3%). Despite this, discontinuations remained infrequent at 6.3%, and the median percentage of intended dose delivered was 88.2%. These data also reflect the success of dose interruptions (used in 66.7% of patients, median 11 days) and reductions (25.4%) as management tools. Concomitant medications, including topical corticosteroids and antihistamines for skin events and diuretics for edema, were commonly employed and generally effective.

Implications for Managed Care

For payers and health systems managing patients with rare, chronic conditions, the MANEUVER data present a notable profile: a treatment with durable response rates across disease subtypes, meaningful improvements in daily physical function, and a safety picture that, although common in terms of event frequency, is predominantly low-grade and manageable without frequent discontinuation. As the treatment landscape for TGCT continues to evolve, longer-term data from pimicotinib's ongoing extension phase will be important in understanding how these benefits and tolerability patterns hold over time.

References

1. Tinoco G, Ravi V, Gelderblom H, et al. Effect of pimicotinib on tumor response and physical function (PF) by tumor location in patients with tenosynovial giant cell tumor (TGCT): results from the phase 3 MANEUVER trial. J Clin Oncol. 2026;44(suppl 16):abstr 11567. doi:10.1200/JCO.2026.44.16_suppl.11567
2. Gelderblom H, Ravi V, Ghori V, et al. Longer-term safety of pimicotinib in tenosynovial giant cell tumor (TGCT): integrated analysis of phase 1 and phase 3 MANEUVER trial data. J Clin Oncol. 2026;44(suppl 16):abstr 11568. doi:10.1200/JCO.2026.44.16_suppl.11568
3. Ravi V, Ghori V, Zhang A, et al. Adverse events and their management in patients with tenosynovial giant cell tumor (TGCT) treated with pimicotinib, after longer-term follow-up from the global phase 3 MANEUVER trial. J Clin Oncol. 2026;44(suppl 16):abstr 11571. doi:10.1200/JCO.2026.44.16_suppl.11571