FDA approves a new Alzheimer's drug. What to know about Eli Lilly's Kisunla

The Food and Drug Administration on Tuesday approved the experimental Alzheimer's drug donanemab, which slowed the early stages of the fatal mind-robbing disease in studies.

The approval comes less than a month after an FDA advisory committee endorsed Eli Lilly's drug , despite questions from advisory committee members about the potential side effects of the drug. The drug is an antibody that removes beta-amyloid that accumulates in the brains of patients with Alzheimer's disease.

Eli Lilly said donanemab will be marketed under the brand name Kisunla as a monthly injection, which will be administered via IV infusion. The Alzheimer's treatment will be available for adults with early symptoms of Alzheimer's disease, which includes mild cognitive impairment and mild dementia. Patients will be tested for amyloid before starting the medication.

Eli Lilly said Kisunla is the only amyloid-targeting drug for which studies provide evidence treatments can be discontinued when amyloid plaques are removed. The company said that can result in lower costs and fewer infusions. The company expects to make the drug available in two weeks, officials said.

Eli Lilly said the price will depend on how quickly the drug clears amyloid plaques from patients. Studies showed 17% of patients completed treatment at six months while 69% took the drug for 18 months. Based on that scenario, Lilly said the drug cost would range from $12,522 for six months to $48,696 for 18 months.

Clinical studies showed people with a mild form of the disease reduced cognitive decline by 35% compared with those who took a placebo. Cognitive decline was assessed by a test that measures memory, thinking and daily functioning.

Kisunla becomes the third amyloid-clearing Alzheimer's drug approved since 2021. Last year, the FDA approved Eisai and Biogen's drug Leqembi but required the drug to provide a warning about the drug's known side effects, which include brain swelling and tiny bleeds. In 2021, the agency approved Biogen's amyloid-clearing drug aducanumab despite mixed results in clinical studies. Biogen halted sales of the drug, sold as Aduhelm , and gave up ownership of it earlier this year.

As it did with Leqembi, the FDA will require Kisunla to include a warning for MRI-visible injuries called amyloid-related imaging abnormalities, or ARIA, which can include brain swelling and tiny bleeds at the surface of the brain. Most people with ARIA-related side effects don't experience symptoms, but serious and life-threatening events do occur, the FDA said.

During the advisory panel hearing last month, Lilly officials said three people died from ARIA-related injuries during the study, and another two who continued taking the drug after the study was completed also died from ARIA injuries.

Patients who carry two copies of the Alzheimer's risk gene, ApoE4, are more likely to get ARIA-related side effects. The FDA said people should take a genetic test to learn whether they carry this genetic risk before starting the treatment.

Joanne Pike, president and CEO of the Alzheimer’s Association, said the new treatment options represent "real progress."

“Today’s approval allows people more options and greater opportunity to have more time,” Pike said in a statement. “Having multiple treatment options is the kind of advancement we’ve all been waiting for – all of us who have been touched, even blindsided, by this difficult and devastating disease.”

This article originally appeared on USA TODAY: FDA approves a new Alzheimer's drug. What to know about Eli Lilly's Kisunla