WASHINGTON — The United States Food and Drug Administration (FDA) has approved pimicotinib, sold under the brand name Pimjetmi, for adults living with symptomatic tenosynovial giant cell tumor (TGCT) for whom surgery could make their movement worse or cause serious harm, the agency announced on 10 November 2026. The decision gives doctors and patients a new oral treatment option for a rare joint tumor that can cause lasting pain, swelling and stiffness, and that often comes back after an operation.
Pimicotinib is a kinase inhibitor taken as a 50-milligram tablet once a day, with or without food, according to the FDA. It works by blocking a protein called colony-stimulating factor-1 receptor, or CSF-1R, whose signaling drives the growth of the tumor cells. The medicine was developed by Abbisko Therapeutics, where it carries the code name ABSK021, and it is marketed in the United States by EMD Serono. China approved the drug in December 2025, the first approval anywhere in the world, before the FDA followed with its own decision nearly a year later.
The approval was based on a global Phase 3 trial called MANEUVER, in which pimicotinib shrank tumors in more than half of the patients who received it: at Week 25, the overall response rate was 56 percent on pimicotinib, compared with 3.2 percent on placebo, the FDA said.
Illustration: A doctor examines a patient's knee — the joint most often affected by tenosynovial giant cell tumor.
What Happened
The FDA announced the approval on 10 November 2026, saying pimicotinib is indicated for adults with symptomatic TGCT for whom surgical resection may cause worsening functional limitation or severe morbidity — in other words, patients whose tumors cannot be removed safely without risking lasting damage to how the joint works. The agency reviewed the drug under its Project Orbis program, an international collaboration in which regulators from several countries review a cancer medicine together. Australia's Therapeutic Goods Administration, Health Canada, the Israel Ministry of Health, Swissmedic and the United Kingdom's Medicines and Healthcare products Regulatory Agency took part in the review, while the European Medicines Agency acted as an official observer, the FDA said.
Pimicotinib had already received two of the FDA's programs for promising medicines: fast track designation and breakthrough therapy designation. Both are designed to speed the development and review of drugs that may offer a meaningful advantage over existing treatments for serious conditions.
The evidence behind the approval came from MANEUVER, a double-blind, randomized, placebo-controlled international Phase 3 trial registered as NCT05804045. Patients enrolled in the trial had confirmed symptomatic TGCT with measurable disease and at least one lesion measuring two centimeters or more. Participants were assigned to receive either pimicotinib or a placebo in a two-to-one ratio, meaning two patients received the drug for every one who received the placebo, and neither the patients nor their doctors knew which treatment they were getting. Randomization was stratified by region, separating patients in China from those outside China, to make sure the two groups were balanced across the regions where the trial was run.
The trial's main measure was the overall response rate at Week 25, judged by blinded independent central review using the standard RECIST version 1.1 criteria for measuring tumor shrinkage. On that measure, 56 percent of patients on pimicotinib responded, with a 95 percent confidence interval of 42 to 68 percent, compared with 3.2 percent on placebo, with a 95 percent confidence interval of 0.1 to 17 percent, according to the FDA. The confidence intervals describe the range within which the true response rate is most likely to fall.
The responses also appeared to last. The median duration of response had not been reached at the time of the analysis, the FDA said, meaning that more than half of the patients who responded were still responding when the data were assessed. Among the responders, 32 patients — 91 percent — had a response lasting at least six months, and 27 patients — 77 percent — had a response lasting at least 12 months.
Beyond tumor shrinkage, the trial measured how patients actually felt and moved. At Week 25, patients on pimicotinib showed statistically significant improvements compared with placebo in active range of motion, measured with a goniometer, an instrument that records how far a joint can bend; in worst pain, measured with the Brief Pain Inventory; and in physical function, measured with the PROMIS Physical Function T-score, a standardized questionnaire about everyday activities. According to CURE Today, all five of the trial's key secondary endpoints were met, a result that suggests the benefits extended beyond the scans to patients' daily lives.
As with any medicine, pimicotinib carries side effects that patients and doctors will need to weigh. The most common adverse reactions, occurring in more than 20 percent of patients, were itching (pruritus), rash, swelling of the face, swelling around the eyes (periorbital edema), fatigue, nausea, headache and swelling of the limbs (peripheral edema), the FDA said. The most common laboratory abnormalities, seen in more than 30 percent of patients, were increases in creatine phosphokinase, lactate dehydrogenase, aspartate aminotransferase, lipase, cholesterol, amylase and alanine aminotransferase. The drug's label carries warnings about liver toxicity (hepatotoxicity), harm to an unborn baby (embryo-fetal toxicity), and increased serum creatinine without affecting kidney function.
Illustration: Laboratory research behind pimicotinib, a CSF-1R inhibitor tested in the global MANEUVER trial.
Background
Tenosynovial giant cell tumor is a rare tumor that grows in the lining of joints, tendon sheaths and bursae — the small fluid-filled sacs that cushion joints. It most often affects the knee, hip, ankle or hand and fingers. The tumor is usually non-cancerous, or benign, meaning it does not typically spread to other parts of the body the way a malignant cancer does. But benign does not mean harmless: a TGCT can damage the joint it grows in, causing pain, swelling, stiffness and a limited range of motion that can make walking, climbing stairs or gripping objects difficult.
Doctors recognize two main types of the disease. Localized TGCT often appears in the fingers or hand and tends to come back less often after treatment. Diffuse TGCT usually affects larger joints such as the knee or hip, grows more widely through the joint lining, and has a higher chance of returning after surgery — up to about 50 to 70 percent after surgery alone, according to patient-advocacy and clinical sources. The diffuse form was formerly known as pigmented villonodular synovitis, or PVNS, a name that older medical literature and some patients still use.
TGCT typically affects young to middle-aged adults, people in the years when work, sport and family life place the greatest demands on their joints. The disease is uncommon: its incidence is roughly 11 to 50 cases per million people per year, according to CancerCare. That rarity is one reason the condition can take time to diagnose, as its symptoms — aching pain, swelling and stiffness — overlap with far more common problems such as arthritis or a sports injury.
The cause lies in a genetic change involving the CSF1 gene. In many tumors the gene is overexpressed, producing too much colony-stimulating factor-1, a signal that draws in large numbers of macrophage-like cells that make up much of the tumor mass. The CSF-1R receptor on those cells is the target pimicotinib blocks.
Surgery has long been the main treatment for TGCT, and it can work well when a tumor is small and localized. But for diffuse disease spread through a large joint, an operation may not remove every affected area, the tumor often returns, and repeat operations can scar the joint further or leave lasting loss of function. That dilemma — a tumor surgery cannot fully remove without damaging the joint — is exactly the situation pimicotinib was approved for.
Pimicotinib is the third CSF-1R inhibitor approved in the United States for TGCT, after pexidartinib (Turalio, 2019) and vimseltinib (Romvimza, February 2025); in its own MOTION trial, vimseltinib showed a 40 percent response rate compared with 0 percent on placebo. Those figures come from separate trials in different patient groups, and no head-to-head trial comparing the three drugs exists, so they should not be read as a ranking. Having a third option matters because individual patients may respond differently to different drugs or tolerate one better than another.
Why It Matters
For people living with TGCT, the approval matters most because of what the disease does to everyday life. A tumor in the knee can make climbing stairs painful; one in the ankle can make walking a short distance an effort; one in the hand can make holding a cup hard. The disease strikes people in their working years, so its effects ripple into jobs and family life. A treatment that shrinks the tumor and improves movement, pain and physical function addresses the problems patients report most often, not only the size of the tumor on a scan.
The MANEUVER results are notable in that they point in the same direction on several measures at once. The tumor shrinkage measured on scans was accompanied by measurable gains in how far joints could move, how much pain patients reported at its worst, and how well they could carry out everyday physical activities. That combination is important for a disease whose burden is felt mainly through pain and lost function, and it is one reason the FDA's review considered the patient-reported and functional outcomes alongside the response rate.
The durability of the responses also matters. That 91 percent of responders were still responding at six months, and 77 percent at twelve months, suggests the benefit is not fleeting for most of those who respond, though the median duration had not yet been reached and longer follow-up will be needed to know how long responses typically last. For a chronic condition that can return again and again after surgery, a medicine that keeps the tumor controlled over time could change how the disease is managed, shifting the balance away from repeated operations.
Illustration: Regaining joint mobility is a central goal of treatment for people living with TGCT.
What Happens Next
With the FDA's approval in hand, the next step is for doctors to begin prescribing pimicotinib to adults who meet the approved indication: symptomatic TGCT where surgical removal could worsen functional limitation or cause severe morbidity. Specialists who treat the disease — typically orthopedic surgeons, oncologists and rheumatologists working together — will need to weigh the trial results against the drug's side effects for each patient, and to monitor liver function and other laboratory values during treatment, in line with the warnings on the label.
Patients considering the drug will want to discuss several questions with their care team. How large is the tumor and how much is it limiting the joint? What has surgery already achieved, and what would another operation risk? How do the most common side effects — itching, rash, swelling and fatigue — compare with the symptoms the tumor itself is causing? And what monitoring will be needed once treatment starts? Because the label warns about liver toxicity and harm to an unborn baby, those conversations will also cover blood tests and, where relevant, contraception during treatment.
Longer-term data from the MANEUVER trial and from patients treated in everyday practice will help answer the questions a single trial cannot: how long responses last beyond the first year, whether gains in movement and function are kept, and how side effects play out over months and years of treatment.
For the research community, the approval adds momentum to work on CSF-1R inhibition and on rare joint tumors more broadly. TGCT is uncommon, but the biology behind it — a gene driving the accumulation of inflammatory cells — is shared with other conditions, and lessons from treating it may inform research elsewhere. For now, the immediate change is simpler: adults with symptomatic TGCT who face surgery that could damage their joint have a new, once-daily oral option, backed by a trial in which more than half of patients saw their tumors shrink and most of those responses were still holding a year later.
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FAQ
What is tenosynovial giant cell tumor (TGCT)?
TGCT is a rare, usually non-cancerous (benign) tumor that grows in the lining of joints, tendon sheaths and bursae, most often in the knee, hip, ankle or hand and fingers. It can cause pain, swelling, stiffness and limited range of motion. There are two types: localized TGCT, often in the fingers or hand, and diffuse TGCT, usually in larger joints, which is more likely to return after surgery. The diffuse type was formerly called pigmented villonodular synovitis (PVNS). TGCT typically affects young to middle-aged adults, and its incidence is roughly 11 to 50 cases per million people per year, according to CancerCare.
What is pimicotinib and how does it work?
Pimicotinib, sold under the brand name Pimjetmi, is a kinase inhibitor developed by Abbisko Therapeutics (code name ABSK021) and marketed in the United States by EMD Serono. It blocks the colony-stimulating factor-1 receptor (CSF-1R), whose signaling drives the growth of TGCT cells. The drug is taken as a 50-milligram tablet once a day, with or without food. It is the third CSF-1R inhibitor approved in the United States for TGCT, after pexidartinib (2019) and vimseltinib (February 2025).
How well did pimicotinib work in the MANEUVER trial?
In the global Phase 3 MANEUVER trial (NCT05804045), the overall response rate at Week 25 was 56 percent on pimicotinib compared with 3.2 percent on placebo, as judged by blinded independent central review using RECIST version 1.1, according to the FDA. The median duration of response had not been reached; 32 responders (91 percent) had responses lasting at least six months and 27 (77 percent) at least 12 months. Patients on pimicotinib also had statistically significant improvements versus placebo in active range of motion, worst pain and physical function, and according to CURE Today all five key secondary endpoints were met.
What are the most common side effects of pimicotinib?
According to the FDA, the most common adverse reactions, occurring in more than 20 percent of patients, were itching, rash, face swelling, swelling around the eyes, fatigue, nausea, headache and swelling of the limbs. The most common laboratory abnormalities, seen in more than 30 percent of patients, were increases in creatine phosphokinase, lactate dehydrogenase, aspartate aminotransferase, lipase, cholesterol, amylase and alanine aminotransferase. The label warns about liver toxicity, harm to an unborn baby and increased serum creatinine without affecting kidney function.
Who can receive pimicotinib?
The FDA approved pimicotinib for adults with symptomatic TGCT for whom surgical resection may cause worsening functional limitation or severe morbidity — that is, patients whose tumors cannot be removed safely without risking lasting damage to how the joint works. Surgery remains the main treatment for many patients, especially when a tumor is small and localized, but for diffuse disease or tumors in difficult locations, a medicine may be the better option. Patients should discuss with their doctors whether pimicotinib is appropriate for them, including the monitoring needed during treatment.
Sources
- U.S. Food and Drug Administration — "FDA approves pimicotinib for symptomatic tenosynovial giant cell tumor" (10 November 2026) — https://www.fda.gov/drugs/cancer-approvals/fda-approves-pimicotinib-symptomatic-tenosynovial-giant-cell-tumor
- CURE Today — "FDA Approves Pimicotinib for Tenosynovial Giant Cell Tumor" (10 November 2026) — https://www.curetoday.com/view/fda-approves-pimicotinib-for-tenosynovial-giant-cell-tumor
- CancerCare — "Treatment Update: Tenosynovial Giant Cell Tumor (TGCT)" (updated 20 May 2026) — https://www.cancercare.org/publications/504-treatment_update__tenosynovial_giant_cell_tumor__tgct_
- Rare Oncology News — "Tenosynovial giant cell tumor (TGCT)" — https://rareoncologynews.com/spotlights/tenosynovial-giant-cell-tumor-tgct/
- ClinicalTrials.gov — MANEUVER trial NCT05804045 — https://clinicaltrials.gov/study/NCT05804045
This article is for general information only and is not medical advice. It does not replace professional medical advice, diagnosis or treatment. Anyone with symptoms of tenosynovial giant cell tumor, or considering any treatment discussed here, should consult a qualified healthcare professional.
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