3 more deaths among patients on Biogen's Aduhelm fuel safety concerns, though no link established: analyst

The death of three additional Alzheimer’s disease patients taking Biogen’s Aduhelm has heaped more concern on the safety of the controversial treatment, though it is too early to determine how the patients died.

The deaths were registered through the FDA’s adverse event reporting system, known as FAERS. Also in the database were reports of amyloid-related imaging abnormalities, or ARIA, a side effect that has been linked to the drug.

In a previous report of the death of another Aduhelm patient last year, analysts at RBC Capital concluded that ARIA was a factor and “was likely due” to Aduhelm. The analysts made their judgement after obtaining a detailed case report of the death through a Freedom of Information Act request.

RBC Capital highlighted the latest information in a note to investors Wednesday.

“Whether these [deaths] were truly drug related or incidental remains difficult to tease apart, though not unexpectedly there were several additional reported cases of ARIA, some associated with seizures,” RBC analyst Brian Abrahams wrote.

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One of the patients who died was 86 years old and had diabetes and heart disease. Another was 74 and had gait disturbance. The third patient's age was not specified; the patient was treated for a seizure, though it was not specified whether it was linked to ARIA.

With three deaths out of a patient population of 427—by RBC’s estimate—during the fourth quarter of last year, the figure is “worth monitoring,” the analysts said. RBC also added that “any potential association” between the newly identified deaths and Aduhelm is “less clear” than the initial case from last year.

For its part, Biogen said none of the deaths reported so far have been linked to Aduhelm.

“Alzheimer’s disease is complex, and patients affected by this devastating disease often suffer from other serious medical conditions,” a company spokesman said in an email.

Biogen took issue with another point made in the RBC report: that “other adverse events and ARIA appear generally in line with the clinical trial population.”

During the trials, serious ARIA events occurred, but most episodes were “mild or moderate,” happened early in the course of treatment and were “often self-resolving and clinically manageable,” the spokesman said.

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“Our ARIA detection and management programs recommend enhanced vigilance for ARIA during the first eight doses of treatment, particularly during the time of titration, as this is the time the majority of ARIA was observed in our clinical trials,” the spokesman said.

Aduhelm’s launch has been beset with problems, and sales have been paltry. The company slashed its annual cost in half following a torrent of criticism over its initial $56,000 price tag. Meanwhile, Medicare has said it will limit its coverage to patients enrolled in clinical trials.