Alzheimer’s is a devastating disease, yet there is division in its causes and treatment options. Leqembi, in a clinical trial, slowed cognitive decline by 27 percent over 18 months compared with a placebo. That represented a five-month delay in progression — dismissed as negligible by some but hailed as a milestone by others for a mainly untreatable malady.

 The Food and Drug Administration is expected to grant Leqembi full approval — the first time such clearance has been granted to a therapy that changes the course of the disease. Other Alzheimer’s drugs treat symptoms, and often not very well. Leqembi’s manufacturer set its list price at $26,500 per year. For Medicare to pay for the drug, patients have to be enrolled in a clinical trial, which will limit coverage.

The price for Leqembi is much higher than recommended by the Institute for Clinical and Economic Review, a Boston-based research group that helps determine fair drug prices. Dr. David Rind, the institute’s chief medical officer, said an appropriate cost for the drug is $8,500 to $20,600 a year.

Broad coverage of Alzheimer’s drug Leqembi would raise future costs for the U.S. Medicare health plan by $2 billion to $5 billion a year, according to a study led by researchers at the University of California, Los Angeles (UCLA).

Skeptics note, however, that the drug’s effectiveness is limited — perhaps too subtle to be noticed by a patient — and that the medication can cause potentially dangerous brain swelling and bleeding. The drug is expensive — $26,500 per year. And Medicare, the federal health program for older Americans, intends to impose coverage conditions, fueling a bitter battle between government officials and advocacy groups.

Because of safety and logistical concerns, most Leqembi prescriptions appear likely to be handled initially at academic medical centers experienced in treating Alzheimer’s patients. They are best equipped to navigate the complex tasks of finding eligible patients and conducting follow-up tests. But even those centers are scrambling to establish safety procedures, find places for infusions and hire more specialists — amid a shortage of dementia experts.

As a result, many medical centers are unlikely to start using Leqembi until mid-autumn or later. If demand surges, patients could face substantial delays in getting the drug. Patients will need evidence of a buildup of amyloid in their brains to get the medication. That is determined by amyloid PET scans — which can cost thousands of dollars and aren’t covered by Medicare except in a limited way in clinical trials — or lumbar punctures, also known as spinal taps. Blood tests are on the horizon but not yet in mainstream use.

Once patients receive Leqembi, they need several brain MRIs to check for side effects. Swelling and bleeding in the brain can usually be safely managed, according to doctors involved in clinical trials of anti-amyloid drugs. They say the side effects are no worse than those for some cancer drugs.

But there were three deaths thought to be linked to Leqembi in an extended portion of its key study. And some patients — including those on blood thinners or with a condition that causes microscopic brain bleeds — could be especially vulnerable to dangerous side effects. If the drug is not handled correctly, some experts worry more people could be injured, and the drug itself could be imperiled.

Medicare has said it plans to cover Leqembi and similar drugs that receive formal FDA approval, but with a caveat: Physicians must participate in registries that collect evidence about how the drugs work in the real world. Collecting such information, Medicare officials say, won’t be a significant burden because doctors will be gathering the data anyway as they assess their patients. Some doctors agree, saying the requirement doesn’t appear onerous and will provide important information on unanswered questions about the drugs.

The Alzheimer’s Association vigorously disagrees, saying the restrictions will delay access. “I think it is going to be a big obstacle, not only because it will take more time and effort for clinicians to prescribe, but also because there will be a delay in setting up” the registries, said R. Scott Turner, a neurology professor at Georgetown University School of Medicine. He and others believe the restrictions also will worsen disparities in Alzheimer’s care.

Even with Medicare coverage, patients could be responsible for more than $5,000 per year in out-of-pocket costs for the drug, according to KFF, a nonprofit health policy organization. And there could be additional costs for brain scans and other services. Private insurers tend to follow Medicare’s lead, so some coverage seems likely once Leqembi gets full FDA approval.

So we see that the FDA is moving with caution, as they should be doing. However, the Alzheimer’s organization that has never met an Alzheimer’s drug they didn’t like wants broad coverage. As stated above, that could cost Medicare over five billion dollars.

The FDA is doing the right thing. Our healthcare system can’t afford a drug whose costs and side effects may be worse than its benefits. HCPs must first be aligned on the causes and possible treatments for Alzheimer’s before any drug receives broad coverage.