Ono poised to join Daiichi in TGCT market after FDA nod

Ono Pharmaceutical has claimed FDA approval for Romvimza as a treatment for tenosynovial giant cell tumour (TGCT), setting up a market tussle with Daiichi Sankyo.

CSF-1R inhibitor Romvimza (vimseltinib) has been approved to treat adults with symptomatic TGCT – a rare non-cancerous tumour that causes inflammation and destruction of joints – if there is a concern that surgery will lead to a serious loss of function or other complications.

It becomes the second FDA-approved drug for the disease after Daiichi Sankyo's Turalio (pexidartinib), a CSF1R, KIT, and FLT3 inhibitor that was cleared by the FDA in 2019 for TGCT associated with severe morbidity or functional limitations and not responsive to improvement with surgery.

Ono – which acquired rights to Romvimza when it bought Deciphera Pharma in a $2.4 billion deal that closed in 2023 – said that the new drug will be "a crucial advancement for the TGCT community" with the "potential to become the new standard of care" for patients in whom surgery is not advised.

The approval follows positive data in the phase 3 MOTION study, which showed a 40% overall response rate (ORR) with Ono's drug at week 25, assessed by a blinded independent radiological review, compared with 0% in a matched placebo group.

In the majority of patients receiving Romvimza (85%), the duration of response was at least six months, while more than half saw a benefit for more than nine months, and the reduced tumour size was accompanied by improvements in active range of motion, patient-reported physical functioning, and patient-reported pain.

According to study investigator Hans Gelderblom of Leiden University Medical Centre in the Netherlands, the new drug is "the first well-tolerated agent to demonstrate significant improvement in a number of other important quality-of-life measures without any observed liver injury as seen with other approved TGCT treatment."

Turalio carries a black box warning on its label for serious and potentially fatal liver injury and has to be made available to patients under a risk evaluation and mitigation strategy (REMS) programme, which means it can only be prescribed by certified healthcare professionals and dispensed by approved pharmacies.

The product has contributed fairly modest sales to Daiichi Sankyo since its launch, making JPY 5.1 billion (around $34 million) in the first nine months of the company's current fiscal year, which was a rise of 25% on the like, year-earlier period.

Ono is hoping to make a greater impact, thanks to its tolerability profile, as well as less frequent dosing. While Turalio needs to be taken orally twice a day, Romvimza is dosed twice a week. The starting dose of Ono's drug is 30mg but can be reduced to 20mg or 14mg if side effects are problematic.

While there is no need for a REMS with Romvimza, patients will have to have blood tests to check liver enzymes before starting treatment, twice a month for the first two months, and then once every three months for the first year.

The list price of Turalio is around $25,000 per month, ahead of discounts, but so far, there is no word on how much Ono intends to charge for Romvimza, which is due to launch this week. It is also under review in Europe, with a decision expected in the coming months.

Additional options for TGCT patients could also be on the way. Last year, German group Merck KGaA reported positive phase 3 results with its once-daily oral CSF-1R inhibitor pimicotinib – licensed from Chinese biotech Abbisko Therapeutics – while SynOx Therapeutics' antibody-based CSF-1R candidate emactuzumab is in the late-stage TANGENT trial looking at two-weekly intravenous dosing.