Biogen and Eisai shares surge after Alzheimer’s drug trial success

Shares in Biogen and Eisai surged on Wednesday after the pharma groups said they would apply for regulatory approval for a new Alzheimer’s drug following a late-stage clinical trial that showed it slowed the rate at which the disease progresses.

The companies said late on Tuesday that the phase-three trial had demonstrated that giving lecanemab, a monoclonal antibody treatment, to patients in the early stages of the disease reduced the rate of cognitive decline by 27 per cent compared with participants who received a placebo.

The results from the clinical trial will provide hope for the roughly 50mn Alzheimer’s sufferers worldwide that progress is being made in the search for treatments to slow the disease. It will also encourage Eli Lilly and Roche, which are conducting trials of similar drugs.

The drug co-developed by Eisai and Biogen reduced the build-up of sticky plaques in the brain known as beta amyloid, which are at the centre of an acrimonious scientific debate about what causes Alzheimer’s disease.

Shares in Biogen jumped almost 45 per cent to $283.44 shortly after the opening bell in New York on Wednesday, while those of Japan’s Eisai, which are listed in Tokyo, climbed 17 per cent. Shares in Eli Lilly and Roche also gained.

Scientists have tried for almost three decades to prove the so-called amyloid hypothesis: the idea that clumps of toxic amyloid cells that bind together in the brain are the primary cause of Alzheimer’s. But dozens of drug trials have failed to prove that clearing the plaques can slow the rate of cognitive decline, causing disappointment for sufferers and their families.

The botched launch last year of Biogen’s aducanumab — the first amyloid-clearing drug to win approval and the first new treatment for the disease in almost two decades — heightened doubts over the amyloid hypothesis.

However, Eisai said the positive results from one of the largest clinical trials of Alzheimer’s patients ever undertaken was a “milestone” and proved the amyloid hypothesis theory.

“Eisai believes these findings will create new horizons in the diagnosis and treatment of Alzheimer’s disease as well as further activate innovation for new treatment options,” said Haruo Naito, Eisai’s chief executive.

Scientists said the lecanemab trial was important because it was the first anti-amyloid treatment to show benefits in terms of slowing cognitive decline, but they nonetheless urged caution in interpreting the results.

“This does become the first of 40-plus trials of around 20 other anti-amyloid treatments to show benefit. While this study is a welcome development, it does not prove the amyloid hypothesis,” said Alberto Espay, professor of neurology at the University of Cincinnati.

He said lecanemab was the first of the anti-amyloid treatments tested that, in addition to lowering amyloid levels, also increased the levels of the normal protein, amyloid-beta 42. Therefore, the benefits may not be because of a reduction in amyloid but because of an increase in the levels of the normal protein, Espay said.

Almost 1,800 patients received lecanemab every two weeks over an 18-month period during the trial, which also showed the drug caused potentially dangerous side effects.

Eisai said it would present the results at an Alzheimer’s conference in November and publish the trial findings in a peer-reviewed medical journal.

Eisai has already applied to the US Food and Drug Administration for accelerated approval of lecanemab based on its ability to clear amyloid plaques. The company said it would now apply for full approval in the US, Japan and Europe.

Evan Seigerman, analyst at BMO Capital markets, said the trial data were strong enough for lecanemab to win regulatory approval and ensure government-funded health schemes provided reimbursement for the drug. Lecanemab’s peak sales could reach $13.3bn per year, he said.