AstraZeneca's Heart Drug Fails to Add Benefit in Trial for ATTR-CM Patients

AstraZeneca detailed the failure of a closely watched clinical trial for a progressive heart disease called ATTR-CM, disclosing that its experimental drug, developed with partner Ionis Pharmaceuticals, showed no additional benefit for patients who were already taking another type of medicine called a stabilizer. Most participants in the Phase 3 trial were on a stabilizer drug when the trial began.

AstraZeneca and Ionis's drug belongs to a class known as "silencers," which are given by injection. The trial found that when patients with ATTR-CM were already taking a stabilizer, an oral drug, adding the silencer produced no measurable improvement, an effect the companies said was strong enough to cause the overall Phase 3 study to miss its goals.

The result has implications beyond AstraZeneca and Ionis. Alnylam Pharmaceuticals, which markets another silencer drug for ATTR-CM, and BridgeBio, which makes a stabilizer drug for the condition, are also affected by the finding. Analysts said the trial's outcome strengthens the case that stabilizer drugs may be more effective than injectable silencer drugs for patients with ATTR-CM.