Biogen shares fell after disappointing data on its Alzheimer's drug

Shares of the drugmaker Biogen fell more than 8% on Tuesday, July 14, following the release of detailed results from a study of a drug to treat Alzheimer’s disease. The data presented failed to convince investors and analysts of the therapy’s effectiveness, despite some signs of clinical benefit.

Biogen shares hit a daily low of $189.4, down 9.4% from the previous day’s closing price. On Tuesday, the company presented detailed results from the Phase 2 trial of diranersen at the Alzheimer's Association International Conference in London.

Investors took note of the company’s announcement that a high dose of the drug resulted in a more significant reduction in tau protein levels, which play a key role in the development of Alzheimer’s disease, according to Bloomberg. However, in May, Biogen reported that the trial had failed to meet its primary endpoint, and that a high dose of diranersen had not been shown to significantly slow the progression of the disease. At that time, the company said that a lower dose appeared to hold more promise, the agency noted.

At the same time, the decline in cognitive function in the group receiving the lower dose of the drug was, on average, 26% less after 76 weeks than in patients receiving a placebo. For higher doses, the effect was no more than 14%.

The published data “raise more questions than they answer,” according to RBC Capital Markets analyst Brian Abrahams, as quoted by Bloomberg. In his view, it remains unclear why the most pronounced clinical effect was observed specifically at the lowest dose. “Even at the optimal dosage, the drug’s effect may not be significant enough to be considered a breakthrough,” said the RBC Capital analyst.

Despite this, the drug has shown some signs of clinical efficacy, which are sufficient to move on to Phase 3 trials, provided the company can determine the optimal dosage, according to David Knopman, a neurologist at the Mayo Clinic, as quoted by Bloomberg.

Biogen announced that it plans to move the drug into the final, Phase 3, stage of clinical trials.

Diranerzen is being developed in collaboration with Ionis Pharmaceuticals and belongs to a new class of drugs that target the tau protein, which is believed to be closely linked to cognitive decline in Alzheimer’s disease, according to Bloomberg. If Phase 3 trials prove successful, the drug could become the first approved therapy of its kind.

Bloomberg noted that current Alzheimer's drugs target amyloid—another type of protein that forms in patients.

This article was AI-translated and verified by a human editor