NEW YORK (CBSNewYork) — A controversial new drug for Alzheimer’s disease has hit another snag in its rollout to patients.

Two major medical systems, including Mount Sinai in New York, have decided against using the drug.

CBS2’s Dr. Max Gomez found out why doctors are reluctant to prescribe it.

Aducanumab, brand name Aduhelm, continues to be mired in controversy over its safety, efficacy and the process that led to its approval.

Last month, an independent advisory committee for the Food and Drug Administration voted nearly unanimously, 11-1, against approving the drug. Yet, the agency, itself, went ahead and granted approval, prompting three of the committee members to resign in protest.

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Two nearly identical clinical trials that manufacturer Biogen submitted to support approval were stopped early because the drug didn’t seem to provide any benefit. A later analysis by Biogen suggested a tiny benefit in a small subgroup of patients.

Dr. Sam Gandy, director of Mount Sinai’s Center for Cognitive Health, said that was among the reasons the Mount Sinai Health System decided to not offer Aduhelm at any of its campuses.

“The benefit is not improvement, but yet but only slowing of decline and decline continues. So the benefit is modest. But it’s really a subtle change on neuropsychological testing. It’s not a day and night change and function,” Gandy said.

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Then recently, allegations of an improper relationship between Biogen and the FDA led the acting FDA commissioner to call for a federal investigation into the drug’s approval.

All this has now also led to a second major medical system, Cleveland Clinic, to decline administering the drug to its patients.

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Biogen continues to stand 100% behind Aduhelm and the clinical data that supported approval, but the federal agency that decides whether to pay for drugs under Medicare and Medicaid has deferred its decision on the drug until next year. Several health insurance companies have already declined to pay the $56,000-a-year cost of the drug.

Dr. Max Gomez