Bristol Myers' lung drug works at low dose, fails at high

Bristol Myers had a mixed but real win Monday. Its drug admilparant passed a major trial for idiopathic pulmonary fibrosis, a disease that scars and stiffens the lungs. Breathing gets harder and harder as it progresses. The lower dose, 60 milligrams, worked: patients lost less lung function than those on placebo over a year. The higher 120-milligram dose, tested in the same trial, did not.

That's the kind of result that cuts both ways. IPF has no cure right now. Admilparant works through a mechanism nobody's ever gotten approved before — blocking a signal called LPA1. A working low dose is genuinely good news for patients. But the high-dose miss raises a real question. Did Bristol Myers pick the wrong doses to test? Or does the drug simply stop helping past a certain amount? The same day, Bristol Myers also reported a second win. RYZ101, a drug it picked up in its RayzeBio acquisition, slowed tumor growth in a rare pancreatic and intestinal cancer.

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Will regulators accept a drug that only works at one of its two tested doses? Companies have won approval that way before, but it usually means a slower, more cautious review. Patients with IPF don't have a lot of other options waiting in line behind this one. So even a narrower approval would matter.