UPDATE: FDA approves Lilly drug that can modestly slow Alzheimer’s disease

The Food and Drug Administration granted approval Tuesday to a closely watched Alzheimer’s drug, concluding that the benefits of modestly slowing the progression of the devastating disease outweigh its risks, Indianapolis-based drugmaker Eli Lilly and Co. announced.

The agency, in a surprise move in March, had delayed approval of the drug to further scrutinize its safety and effectiveness. Last month, a panel of independent experts unanimously endorsed the drug, setting the stage for the FDA’s sign-off.

Eli Lilly’s drug—Kisunla, the brand name for donanemab—is one of the few treatments developed for Alzheimer’s that modifies the underlying disease and will join just one other drug, Leqembi, on the commercial market. Kisunla—which was approved for treatment of early symptomatic Alzheimer’s disease—doesn’t halt the disease, but it has been shown to slow cognitive and functional decline.

“I think it’s likely to be the highlight of the year for us,” said Daniel Skovronsky, Eli Lilly’s chief scientific officer, noting that there are “few diseases that are as feared with as few treatment options” as Alzheimer’s. He said Kisunla will be available to patients in the coming weeks.

The debates over such drugs have been particularly fraught because there is no cure for the affliction affecting more than 6 million Americans. Advocates have urged treatments for the memory-robbing disease that levies a harsh toll on families, but the medications have been dogged by complications such as bleeding in the brain.

Kisunla slowed the cognitive and functional decline in patients with mild cognitive impairment by 35 percent over 18 months, a clinical trial found. The drug works by clearing a sticky plaque in the brain called amyloid beta, which is associated with the disease.

Eli Lilly is pursuing an even bolder ambition: conducting trials to see whether the drug can prevent Alzheimer’s by clearing amyloid in patients that don’t yet show symptoms.

The total cost of Kisunla will vary by patient depending on when they complete the treatment. That’s because once a scan shows a patient has minimal levels of amyloid, they can discontinue the treatment.

The estimated cost for a six-month course of the therapy is $12,522. A full year of treatment is projected to cost $32,000, according to the drugmaker. However, many people probably will not pay the full list price in part since Medicare is expected to cover the treatment for certain patients.

For some, the price could be higher than Leqembi’s estimated cost of $26,500 per year, although that treatment does not stop after the amyloid clears.

Kisunla is the third amyloid-targeting drug to win the FDA’s blessing since 2021, following two treatments—Aduhelm and Leqembi— jointly developed by drugmakers Eisai and Biogen.

The approval of Aduhelm deeply divided the medical community, as critics argued that there was not enough evidence to show that the drug worked. The drugmakers stopped marketing Aduhelm after it fizzled commercially. But Leqembi received a warmer reception because later-stage data showed the treatment slowed cognitive and functional decline by 27 percent over 18 months, while Aduhelm had conflicting data.

Still, like the anti-amyloid drugs that came before it, donanemab has not been free of controversy. Three patients who received the drug in a clinical trial died of a complication from the drug. The condition, called ARIA, can cause the brain to swell or bleed. No such deaths occurred in the placebo group.

Critics have also said that donanemab’s benefits, while statistically significant, are modest. Members of the advisory committee cautioned that the risks and benefits could vary depending on patients’ genetics and the stage of their disease.

In briefing documents last month, the FDA had signaled that it was not overly alarmed by the drug’s safety profile, writing that the findings “are generally consistent” with the class of drugs that aim to reduce or eliminate amyloid plaques.

Though far from a cure, the recent Alzheimer’s drugs have kindled excitement among some researchers and advocates because of the potential to modify the course of the disease—effectively buying more time for those who suffer from it.

“Having multiple treatment options is the kind of advancement we’ve all been waiting for—all of us who have been touched, even blindsided, by this difficult and devastating disease,” Joanne Pike, head of the Alzheimer’s Association, said in a statement.

The drug is administered by infusion once a month. A key feature of Eli Lilly’s approach is that treatment with the drug could be discontinued once a patient’s amyloid levels are reduced to a certain level. That could reduce the burden on patients, but it remains unclear how testing for amyloid should be conducted.

The approval isn’t likely to give a meaningful boost to Lilly’s profits in the near term.The Indianapolis-based firm has a stock-market value of nearly $820 billion—the eighth-highest among publicly traded U.S. companies, and the most of any pharmaceutical firm, according to S&P Global Market Intelligence. The company’s rising stock price, which closed at $906.71 on Tuesday, has largely been driven by the runaway success of its diabetes and weight-loss drugs, Mounjaro and Zepbound, respectively.

Still, the approval marks a significant success for Lilly and could buoy the prospects of other amyloid-targeting drugs, according to Wall Street analysts.