BiogenDemand for Biogen’s (NSDQ:BIIB) monoclonal antibody Aduhelm (aducanumab) has been weak, leading the company to cut the wholesale cost of the drug in half to $28,200 for patients with an average weight.

Now, Medicare officials reached a preliminary conclusion that federal coverage of the drug should be limited to clinical trial participants.

The agency went further, stating that coverage of the broader class of monoclonal antibodies targeting amyloid for Alzheimer’s would be limited to CMS-approved randomized controlled trials and trials supported by the NIH.

“This proposed decision will enable researchers to collect crucial data to evaluate the clinical benefits of these drugs,” wrote Dr. Richard J. Hodes, director, National Institute on Aging at NIH, in a statement.

Last week, Bloomberg published an op-ed recommending that Medicare coverage of Aduhelm be constrained to clinical trial participants.

In after-hours trading, BIIB shares fell 6.97% to $241.52. The stock is now trading lower than it was a year ago. BIIB shares were valued at $267.39 on January 12, 2021, hitting a high of $414.71 on July 10, 2021.

In advance of the Medicare decision, Biogen announced that it would host an analyst Q&A call on January 13, 2022, at 8:00 a.m. ET.

Biogen released a statement saying that Medicare’s decision “denies the daily burden of people living with Alzheimer’s disease,” excluding “almost all patients who may benefit.”

CMS will open a 30-day public comment to obtain feedback regarding the preliminary decision.

It will likely release its final decision regarding Aduhelm in April.

Last year, an FDA advisory panel recommended against FDA approval of the drug. After the agency decided to conditionally approve aducanumab anyway, three of the committee members resigned.