U.S. regulators are slated to decide by Monday whether to approve Biogen Inc’s (NASDAQ:BIIB) much-talked-about Alzheimer’s disease drug, aducanumab.

The Decision: Wall Street analysts and industry observers are divided on its chances of approval. Some analysts are betting on approval, while others put the chances well below 50%, Reuters reports.

If approved, Biogen’s aducanumab would be the first treatment to address an underlying cause of the condition.

Aducanumab was studied in patients with early disease. Some trial patients needed to be monitored for brain swelling.

The FDA decision will impact not only Biogen and its partner Eisai Co Ltd (OTC:ESALY), but other drugmakers developing Alzheimer’s drugs, such as Eli Lilly & Co (NYSE:LLY).

Aducanumab is a monoclonal antibody that targets part of beta-amyloid, an abnormal protein that accumulates in the brains of Alzheimer’s patients.

All previous experimental medicines employing the same approach to Alzheimer’s so far have failed.

Patient advocates are lobbying for the drug to be approved, citing the high unmet medical need, but many doctors remain skeptical.

In November 2020, the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee voted against recommending the drug. Broadly, the criticism is that the drug’s efficacy has not been proven, and there are doubts if the drug’s risk-benefit profile is worth approval.

“We support a decision for approval of aducanumab ... It ushers in a new era of potential treatments,” Dr. Joanne Pike, chief strategy officer at the Alzheimer’s Association, told Reuters.

Analyst Views: Oppenheimer last month raised to 50% from 33% its odds for an aducanumab approval, citing comments from Biogen that it is preparing for a commercial launch.

“If the FDA approves aducanumab, it could go to around $400, and if not, to around $200,” Mizuho Securities analyst Salim Syed said in a recent research note.

Bank of America Securities analyst Geoff Meacham said in an interview that he puts the odds at 75% that the FDA will not approve Biogen’s drug.

Analysts have also speculated that the FDA could put forward limiting aducanumab’s use to certain patients, for instance, or requiring more data to prove that the drug is effective.

Related content: Benzinga's Full FDA Calendar.

Price Action: BIIB shares are up 4.93% at $285.97 during the market session on the last check Friday.