Bristol Myers said a late-stage study in idiopathic pulmonary fibrosis showed the lower dose of admilparant helped patients breathe better than placebo, while the higher dose did not show a significant benefit. Even so, people in all three study arms kept getting worse over time.
A patient death previously reported occurred in the higher dose group. An external, independent adjudication committee concluded it was unlikely to be related to treatment, according to the company. Trial liver events were limited, mostly mild and short lived, and largely seen in patients who were also taking drugs associated with liver issues.
Admilparant inhibits the lysophosphatidic acid receptor, a signaling route associated with tissue inflammation and fibrosis. According to Bristol, the drug may represent the inaugural therapy of its class for pulmonary fibrosis, a chronic condition that damages and stiffens the lungs and may result in death within three to five years. He called the results an "important advancement" for treating the condition.
Separately, a pivotal study in gastroenteropancreatic neuroendocrine tumors found RYZ101 significantly delayed disease progression at a preplanned interim readout. These uncommon tumors originate in hormone-producing cells within the gastrointestinal tract or in the pancreas. The study enrolled patients whose disease had advanced after receiving a different form of radiation.
Bristol describes RYZ101 as a targeted radiation treatment delivered directly to tumors. The US Food and Drug Administration granted the therapy orphan drug designation in 2026. Bristol acquired RayzeBio, the original developer, for $3.7 billion in 2024.
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Investors were watching both programs because they tackle hard diseases with new approaches, and success could help counter future patent expirations. But there are caveats. RBC Capital Markets analyst Trung Huynh called it "slightly concerning" that the higher dose of admilparant failed to show a clear edge, and said full disclosure of the results is needed to address outstanding questions.
He added that the higher dose was likely meant to set the drug apart from competitors, which now looks off the table. "The trial meeting its primary endpoint could be sufficient to support admilparant regulatory approval, but the lack of dose response raises questions about its profile," wrote David Risinger at Leerink Partners. "We await detailed results." By 1:41 p.m.
Monday in New York, Bristol Myers shares were down 3.7%, following a 9.6% increase year-to-date through Friday's close.
Bristol plans to sit down with regulators to review the admilparant data, which would then be evaluated for a potential approval, and will share the results at a future medical meeting. The drug is also in a final-stage study for progressive pulmonary fibrosis, with initial data expected next year. If the low dose holds up and the profile checks out, Bristol could add a first-in-class fibrosis therapy and a targeted radiotherapy for rare tumors to its lineup, a combo that could help reshape its growth path as older blockbusters face patent cliffs.
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