VietJoy

SAN DIEGO/CHICAGO - Biogen Inc on Thursday presented new data on its experimental Alzheimer’s drug aducanumab that eased concerns raised by some experts but still left many questions unanswered as the company made its case about why it plans to seek U.S. approval after declaring the drug a failure in March.

Experts had been watching closely for any statistical abnormalities or excess safety issues that would affect how the drug is reviewed by the U.S. Food and Drug Administration (FDA), likely in the second half of 2020.

It has been at least 15 years since the FDA has reviewed an application for a new Alzheimer’s treatment, and an agent that can slow progression of the mind-wasting disease is desperately needed.

Alzheimer’s experts on a panel organized by the company, who had seen the data previously, expressed confidence that the complicated study did show that the drug was able to slow progression of the disease.

“All of the data suggests this is a disease modification. That means the impact of the treatment will continue to accrue with time,” said Dr. Paul Aisen, an Alzheimer’s expert from the University of Southern California.

Dr. Ronald Petersen, an Alzheimer’s expert from Mayo Clinic who moderated the panel and has been a paid adviser for Biogen, said while one of the two studies, known as Emerge, was “overwhelmingly positive,” the twin study known as Engage, was not. “Overall, I think it’s more positive than negative,” he said of the results.

Petersen was not too worried about the rates of a brain swelling side effect, known as ARIA-E, which occurred in 33-35 percent of patients in the high-dose groups.

“The side effects are there. They’re not zero. They’re to be expected. But I think they’re manageable.”

Others, however, acknowledged that the affected sample size was small and the trials were cut short early. Only one of the two phase 3 trials showed a statistically significant benefit.

“This reinforces what I thought before. That we need a third study. The data are encouraging, but there are still questions about whether the drug has a clinical effect,” said Dr. Howard Fillit, chief science officer of the Alzheimer’s Drug Discovery Foundation, who was at the meeting.

Fillit said the company only measured one timepoint - 78 weeks after treatment. “It still remains to be seen if this effect is sustained. It could be an anomaly.”

Dr. Eric Siemers, a former Alzheimer’s researcher for Eli Lilly and a consultant on drugs for neurodegenerative disease who was not involved with the study, said based on his read of the data, the patient responses are not happening by chance.

“The regulators will have a very difficult job. Do you look at the totality of the data, or require more study, which would be years away,” he said.

Stifel analyst Paul Matteis said in a note to clients that he saw aspects that were both “incrementally better and worse than expected,” and puts the probability of the drug winning approval at less than 50%.

Biogen’s shares had been halted prior to the presentation at a Alzheimer’s meeting, reopened lower, and then rose as investors tried to parse the meeting from the complicated study.

Biogen has partnered with Japan’s Eisai Co Ltd to develop aducanumab as well as BAN2401, which works in a similar way.