Lilly Alzheimer drug faces more delays as FDA plans hearing

Eli Lilly’s Alzheimer’s disease drug donanemab faces further delays in gaining approval, with US regulators planning to hold a hearing of external advisers to explore how safe the therapy is and how well it works.

The US Food and Drug Administration’s (FDA) decision to hold an advisory panel hearing is a major surprise and comes just weeks before the FDA was expected to rule on approving the drug.

The agency wants to hear from outside experts “to further understand topics related to evaluating the safety and efficacy” of donanemab, Lilly said on Friday (Mar 8) in a statement. The meeting date hasn’t yet been set.

The new delay is the latest in a string of setbacks for the drug, which removes a toxic protein called amyloid from the brains of Alzheimer’s patients and helped slow cognitive decline in a large trial. In studies, side effects included brain swelling and brain bleeding, and regular monitoring is required to detect these issues early before they cause problems.

In an interview, Lilly executives said the FDA’s last–minute move to convene the external committee would likely delay a decision on the drug for a few months, as it will take the agency time to organise and schedule the meeting.  

“We just found out very, very recently,” that the agency had decided to hold the hearing, said Anne White, a company executive vice president and president of Lilly Neuroscience. 

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Among other things, she said that the agency wants to explore “unique aspects” of Lilly’s main donanemab trial, including the fact that some patients are able to stop taking the drug after all the amyloid is cleared from their brains, as well as unspecified topics related to safety. She said that the agency had indicated it wants to move quickly to organise the hearing.

While advisory panel hearings are common before major drug approvals, Lilly called the decision to hold the hearing at such a late stage “unexpected” and “unusual.” Company executives were confident that the drug offered clear benefits to patients.

Lilly initially applied for accelerated approval, based on second-stage trial results showing the drug could lower brain amyloid levels. But in January 2023 the FDA refused to grant this conditional approval and asked Lilly to submit a traditional drug application with data from the larger phase 3 trial, which Lilly did last year.

The FDA then asked for an extension on reviewing this additional data, pushing off a final decision until early this year, Lilly executives said in November. Before this latest delay, Lilly had repeatedly said that a final decision would come by the end of the first quarter.

As recently as just two days ago, Lilly executives insisted everything with the review was proceeding normally. “It’s a completely normal experience so far,” Andrew Adams, a senior vice president at the drugmaker, said in a presentation at a TD Cowen investor conference on Wednesday. “As far as I’m aware, everything is completely normal, yes. You’d have to ask the agency for their view, but from our side, everything’s completely normal.” 

If the drug is approved, it would compete with Eisai’s Leqembi, which received full FDA approval to treat Alzheimer’s in July. BLOOMBERG