Biogen, Eisai Alzheimer's Data Shows Need for Further Study

(Bloomberg) -- Biogen Inc. and Eisai Co. released additional data about their experimental Alzheimer’s drug that raised new questions and indicated more work will likely be needed to study the drug’s effects on patients.

Key Insights

  • The companies said that the slowing of the progression of Alzheimer’s disease observed in the trial was likely due to the drug, known as BAN2401, and not the way the clinical study was set up.
  • Analysts had been concerned that the observed effects stemmed from comparing patients who have a genetic marker that may mean the disease progresses faster to a group who lack the mutation.
  • Patients with the genetic mutation, known as APOE4, seemed to respond the best to the highest dose of the drug, suggesting that efforts to limit their numbers in the high-dose group may have actually led to an underestimation of the treatment’s benefits. Those patients saw 63 percent less decline in disease progression, better than the 7 percent seen in those without the genetic marker.

Know More

  • Biogen Chief Medical Officer Al Sandrock said he sees “signals” of clinical effectiveness in the trials, a term that suggests a benefit but doesn’t confirm it. “This gives me cautious optimism that we’re on the right track,” he said in a telephone interview.
  • Only 10 of the 48 patients with the APOE4 mutation enrolled in the high-dose group had data at the key 18-month mark, in part because patients who developed brain swelling known as ARIA were required to drop out of the trial.
  • Eisai and Biogen are in talks with regulators about the future of the compound, and Sandrock declined to comment on whether additional research is needed to get BAN-2401 onto the market. Investors had hoped the companies could file for an accelerated approval based on the current results, with confirmatory trials to come later.

Market Reaction

Biogen shares declined as much as 4.5 percent but were recently down less than 1 percent amid a wider rally in U.S. stocks. U.S.-traded shares of Eisai were down 5.8 percent at 11:32 a.m. in New York.

©2018 Bloomberg L.P.