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FDA approves a third CSF-1R inhibitor for a rare joint tumor

FDA approves a third CSF-1R inhibitor for a rare joint tumor

New Capabilities

Pimjetmi offers once-daily dosing and, unlike Turalio, no boxed warning for liver toxicity.

Yesterday: FDA approves Pimjetmi for symptomatic TGCT

Overview

Updated 1 hour ago

Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive growth in the joints, tendon sheaths and bursae. For patients whose tumor sits where surgery would damage the joint more than the disease, treatment options have been limited.

On November 10, 2026, the Food and Drug Administration approved pimicotinib, sold as Pimjetmi, for adults with symptomatic TGCT when surgery may cause worsening functional limitation or severe morbidity. It is the third drug in a class that blocks colony-stimulating factor-1 receptor (CSF-1R), after pexidartinib in 2019 and vimseltinib in 2025.

Why it matters

For people with TGCT, a once-daily pill now offers an alternative to surgery or a drug carrying a liver warning.

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Key Indicators

56
Objective response rate at week 25 (pimicotinib)
Versus 3.2% on placebo in the MANEUVER trial, as assessed by blinded independent central review.
3.2
Objective response rate at week 25 (placebo)
The placebo arm's response rate in the same trial.
91
Responders with response lasting at least 6 months
32 of 35 responders in the pimicotinib arm.
77
Responders with response lasting at least 12 months
Median duration of response was not reached in the trial.
50 mg
Recommended dose
Taken orally once daily, with or without food.
43
Estimated annual TGCT incidence per million person-years
Global estimate cited by Pharmacy Times.

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Organizations Involved

AT
Abbisko Therapeutics
Biotechnology company
Discoverer and licensor of pimicotinib

Shanghai biotech that discovered pimicotinib and licensed worldwide commercialization rights to Merck KGaA.
Merck KGaA, Darmstadt, Germany
Merck KGaA, Darmstadt, Germany
Pharmaceutical and science company
Holder of worldwide commercialization rights to pimicotinib

Darmstadt-based company that licensed pimicotinib from Abbisko and will commercialize it globally.
EMD Serono
EMD Serono
U.S. pharmaceutical subsidiary
Sponsor of the Pimjetmi FDA application

Merck KGaA's U.S. biopharma arm, which holds the Pimjetmi approval and will sell it in the United States.
U.S. Food and Drug Administration
U.S. Food and Drug Administration
Federal regulator
Approved pimicotinib on November 10, 2026

The U.S. agency that approved pimicotinib and set the label's warnings and dosing.

Timeline

2023 November 2026

6 events Latest: Yesterday
Tap a bar to jump to that date

  1. FDA approves Pimjetmi for symptomatic TGCT

    Latest Regulatory

    The agency clears pimicotinib for adults when surgery may cause worsening functional limitation or severe morbidity.

  2. Swissmedic approves pimicotinib

    Regulatory

    Switzerland becomes the third approval ahead of the U.S. decision.

  3. Health Canada approves pimicotinib

    Regulatory

    Canada becomes the second country to clear the drug.

  4. China's NMPA grants first approval

    Regulatory

    The National Medical Products Administration approves pimicotinib, the first clearance worldwide.

  5. Merck exercises worldwide option after positive trial results

    Business

    Merck pays an $85 million option fee and takes global rights; MANEUVER topline data show a 54% response rate versus 3.2% for placebo.

  6. Abbisko and Merck KGaA sign pimicotinib licensing deal

    Business

    The agreement covers commercialization rights in mainland China, Hong Kong, Macau and Taiwan.

Scenarios

1

European regulators approve pimicotinib

Likely Resolves by End of 2027

Discussed by: Merck KGaA's stated global commercialization plan

Pimicotinib already has approvals in China, Canada and Switzerland. Merck holds worldwide rights and has described a global rollout. A European Medicines Agency marketing authorization would extend that rollout to the continent's largest market.

2

FDA adds a boxed liver warning to Pimjetmi

Unlikely Resolves by Nov 10, 2028

Discussed by: Clinical trial investigators, who reported no cholestatic hepatotoxicity in MANEUVER

Pexidartinib, the first CSF-1R inhibitor for TGCT, carries a boxed warning for fatal cholestatic hepatotoxicity and a Risk Evaluation and Mitigation Strategy. Pimicotinib's label carries hepatotoxicity warnings but no boxed warning. Post-market liver injury reports could change that.

3

Pimicotinib advances in chronic graft-versus-host disease

Possible Resolves by End of 2028

Discussed by: Merck KGaA and Abbisko, which have said they will explore the drug in cGvHD

Both companies have named chronic graft-versus-host disease as an additional indication to test. A phase 3 trial or regulatory submission would move the drug beyond TGCT and into a larger patient population.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2019

Pexidartinib approval (2019)

The FDA approved pexidartinib, sold as Turalio, as the first systemic therapy for TGCT. In the pivotal ENLIVEN trial, the week-25 objective response rate was about 39%. The label carried a boxed warning for fatal cholestatic hepatotoxicity and an FDA-mandated Risk Evaluation and Mitigation Strategy.

Then

Patients gained a non-surgical option, but access required liver monitoring and enrollment in a restricted distribution program.

Now

The boxed warning became the safety benchmark that later CSF-1R inhibitors had to clear.

Why this matters now

Pimicotinib's label has hepatotoxicity warnings but no boxed warning, and trial investigators reported no cholestatic hepatotoxicity.

2025

Vimseltinib approval (2025)

The FDA approved vimseltinib, sold as Romvimza, a second CSF-1R inhibitor for TGCT. The MOTION trial showed a week-25 response rate of about 40%. It is taken twice weekly, with at least 72 hours between doses, and avoided the liver toxicity warnings that constrained pexidartinib.

Then

Patients got a second systemic option with a different dosing schedule and no boxed liver warning.

Now

The class shifted from a single drug with a restrictive safety program to a competitive market.

Why this matters now

Pimicotinib enters as the third option, with once-daily dosing and a similar safety profile to vimseltinib.

Sources

(7)
+1
FDA EMD Serono PR Newswire Fierce Pharma Pharmacy Times Merck KGaA Drugs.com