Following the FDA’s approval of Leqembi (lecanemab), a monoclonal antibody that targets and helps destroy the hallmark beta-amyloid in Alzheimer's patients, the Centers for Medicare and Medicaid Services have proposed ending the once-per-lifetime limit on beta-amyloid PET scans.

The agency currently covers only one amyloid PET scan for a patient in their lifetime, and they must be enrolled in a clinical trial. The FDA initially gave Leqembi the green light in January, through its Accelerated Approval Pathway, and full approval this summer based on the result of a large clinical trial, published in The Lancet, that showed the drug slowed down the rate of cognitive and functional decline in patients by 27%, compared to a placebo.

Leqembi requires preliminary testing to determine the extent of amyloid plaques, intravenous infusions administered every other week, and periodic brain scans to assess for potential side effects, reported Reuters.
Additionally, other new drugs made for the same purpose are showing promise. Eli Lilly’s donanemab significantly slowed clinical progression at 76 weeks, according to research published this month in JAMA Network.

"With the recent development of treatments directed against amyloid, the PET scan would help to confirm the presence of brain amyloid, to alter the course of treatment for the patient and to demonstrate treatment results. In addition, the PET AB can be used to better select patients for AD trials such as anti-amyloid treatment trials," said CMS administrator Chiquita Brooks-LaSure in a statement.

Under the proposal, coverage would be left up to regional contractors, a decision that is likely to create confusion, TD Cowen analyst Eric Assaraf told Reuters.

According to the Society of Nuclear Medicine & Molecular Imaging, amyloid PET scans are the gold standard in clinical testing for detecting the plaques in the brain, and the only noninvasive option. Another alternative, lumbar punctures, are less accurate and more painful, and approximately 35% of patients refuse or are unable to undergo it.

“Amyloid PET scans are an essential tool that will allow physicians to identify appropriate candidates for Leqembi. PET scans should also be performed on patients after they begin taking lecanemab to ensure that the amount of amyloid plaque has decreased,” said SNMMI president Dr. Helen Nadel in a statement.

Beta-amyloid PET scanning also falls under CMS’ Coverage with Evidence Development Policy, in which CMS agrees to reimburse for services undergoing clinical trials as a way of evaluating if it justifies covering them in clinical settings.

Patrick Hope, executive director of the Medical Imaging & Technology Alliance (MITA), says that “it’s essential that CMS remove beta-amyloid PET from the CED policy to ensure that Alzheimer’s patients receive an accurate diagnosis in order to benefit from Leqembi.”

CMS has set up a 30-day comment period, which began on July 17, for the proposal.

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