Ono’s Romvimza gains FDA approval for rare joint tumor treatment

USA – Ono Pharmaceutical has secured FDA approval for Romvimza (vimseltinib) as a treatment for tenosynovial giant cell tumor (TGCT), a rare, non-cancerous tumor that causes joint inflammation and damage.

This approval places Ono in direct competition with Daiichi Sankyo, which introduced the first FDA-approved TGCT drug, Turalio (pexidartinib), in 2019.

A new alternative for TGCT patients

Romvimza is approved for adults with symptomatic TGCT when surgery is not a safe or effective option due to the risk of serious complications or loss of function.

As a CSF-1R inhibitor, the drug works by targeting the colony-stimulating factor 1 receptor (CSF-1R), a key player in the growth of these tumors.

Ono acquired Romvimza through its US $2.4 billion acquisition of Deciphera Pharma in 2023 and is optimistic about the drug’s impact.

The company stated that the approval is “a crucial advancement for the TGCT community” and believes Romvimza has the potential to become the new standard of care for patients who cannot undergo surgery.

How Romvimza stands out

The approval is based on strong results from the phase 3 MOTION trial, which showed that 40% of patients treated with Romvimza experienced a significant reduction in tumor size after 25 weeks, compared to 0% in the placebo group.

Additionally, most patients (85%) maintained their response for at least six months, while more than half saw benefits lasting over nine months. The treatment also improved joint movement, physical function, and reduced pain.

Dr. Hans Gelderblom of Leiden University Medical Centre highlighted that Romvimza is the first well-tolerated treatment that significantly improves quality of life for TGCT patients without causing liver damage, a key concern with existing treatments.

Comparing Romvimza and Turalio

Turalio, the first approved TGCT treatment, comes with serious safety concerns, including a black box warning for potentially fatal liver damage.

Due to this risk, it is only available through a strict Risk Evaluation and Mitigation Strategy (REMS) program, which requires patients to receive the drug from certified healthcare providers and approved pharmacies.

In contrast, Romvimza does not require a REMS program, making it more accessible. However, patients will need regular blood tests to monitor liver enzymes—twice a month for the first two months, then every three months for the first year.

Another advantage is its less frequent dosing. Turalio is taken twice daily as an oral pill, while Romvimza is administered twice a week, with the option to adjust the dosage (30mg, 20mg, or 14mg) depending on side effects.

Market impact and future developments

So far, Turalio’s sales have been modest, generating JPY 5.1 billion (about US $34 million) in the first nine months of Daiichi Sankyo’s current fiscal year, despite a 25% year-over-year increase.

Ono aims for a stronger market presence, thanks to Romvimza’s better safety profile and dosing convenience.

Pricing details for Romvimza have not yet been announced, but Turalio costs approximately US $25,000 per month before discounts.

Romvimza is set to launch this week and is also under review in Europe, with a decision expected in the coming months.

Meanwhile, other TGCT treatments are in development. Merck KGaA is testing pimicotinib, a once-daily oral CSF-1R inhibitor, while SynOx Therapeutics is advancing emactuzumab, an antibody-based CSF-1R treatment administered every two weeks via IV.