A new FDA approval stands to give Daiichi Sankyo’s Turalio some company in a rare tumor type.

Fellow Japanese drugmaker Ono Pharmaceutical has won an FDA green light for vimseltinib to treat adult patients with symptomatic tenosynovial giant cell tumor (TGCT), which is typically noncancerous growth that affect the joints.

The drug, now known under the brand name Romvimza, is approved for TGCT cases in which surgery would potentially worsen a patient’s bodily function or cause severe illness.

Like Turalio, which in 2019 became the first FDA-approved therapy to treat TGCT, Romvimza is also an inhibitor of the colony-stimulating factor 1 receptor (CSF1R).

Romvimza only recently came into Ono’s possession after the Japanese pharma last year paid $2.4 billion to acquire Deciphera Pharmaceuticals and made the U.S. company its subsidiary. At that time, Ono CEO Gyo Sagara described the acquisition as an opportunity to expand Ono’s targeted oncology portfolio, accelerate its business development in the U.S. and Europe and strengthen its kinase drug discovery capabilities.

Romvimza’s approval is based on findings from the MOTION trial. At Week 25, treatment with Romvimza elicited a response in 40% of TGCT patients for whom surgery was not suitable, versus 0% among those who received placebo. After an additional six months of follow-up, 85% of responders saw their responses last for at least six months, and 58% could say the same for at least nine months.

The better tumor response performance was backed by statistically significant improvements in active range of motion, patient-reported physical functioning and patient-reported pain, as well.

Back in 2019, Daiichi's Turalio scored its FDA approval based on a 39% overall response rate at Week 25, versus 0% for placebo, also in TGCT patients for whom surgery was not recommended. Among patients who had been followed for a minimum of six months, 96% maintained their responses for at least six months.

One advantage Romvimza boasts is its convenience. The Ono drug is dosed at 30 mg twice weekly, whereas the Daiichi option is given at 250 mg twice daily. Both are oral meds.

What’s more, because of concerns over “serious and potentially fatal liver injury”—which is highlighted in a black box warning—Turalio is available only through a restricted Risk Evaluation and Mitigation Strategy (REMS) program. In Turalio’s phase 3 trial, the data monitoring committee had to stop enrollment early after noticing cholestatic liver toxicity.

In the MOTION trial, investigators didn’t notice any evidence of cholestatic hepatotoxicity or drug-induced liver jury. Ten percent of patients receiving Romvimza experienced treatment-emergent grade 3 or 4 elevated blood creatine phosphokinase, which indicates muscle injury or stress.

Romvimza’s label doesn’t include any boxed warning or REMS requirement. 

Both Romvimza and Turalio might soon have to face another competitor. Merck KGaA recently said a phase 3 TGCT trial of its CSF1R inhibitor pimicotinib, for which the German pharma licensed some rights from China’s Abbisko Therapeutics, also hit its goal with a 54% overall response rate. 

Turalio generated 5.1 billion Japanese yen ($33 million) of sales during the last nine months of 2024, up 25% year over year.