FDA approves second drug to slow Alzheimer's progression

US officials have approved another Alzheimer's drug that can modestly slow the disease.  

This approval provides a new option for patients in the early stages of the incurable, memory-destroying ailment, according to The Canadian Press. 

The Food and Drug Administration approved Eli Lilly’s Kisunla on Tuesday for mild or early cases of dementia caused by Alzheimer’s. This drug is only the second shown to convincingly delay cognitive decline in patients, following last year’s approval of a similar drug from Japanese drugmaker Eisai.   

The delay provided by both drugs amounts to about seven months for Lilly’s drug. Patients and their families must weigh this benefit against downsides like regular IV infusions and potentially dangerous side effects, such as brain swelling.   

Physicians who treat Alzheimer’s consider the approval a significant step after decades of failed treatments.  

Suzanne Schindler, a neurologist at Washington University in St. Louis, expressed her excitement, “I’m thrilled to have different options to help my patients. It’s been difficult as a dementia specialist — I diagnose my patients with Alzheimer’s and then every year I see them get worse and they progress until they die.”   

Both Kisunla and the Japanese drug, Leqembi, are laboratory-made antibodies administered by IV. They target sticky amyloid plaque buildup in the brain, a contributor to Alzheimer’s. However, questions remain about which patients should receive the drugs and how long they might benefit.   

The approval of the new drug was anticipated after an outside panel of FDA advisors unanimously voted in favour of its benefits last month.  

This endorsement came despite questions from FDA reviewers about how Lilly studied the drug, including allowing patients to discontinue treatment once their plaque levels became very low.   

Lilly stated that costs would vary based on the duration of the treatment, with a year’s therapy costing $32,000. This price is higher than the $26,500 annual cost of Leqembi. The FDA’s prescribing information suggests that doctors can consider stopping the drug after confirming minimal plaque via brain scans.   

More than 6 million Americans have Alzheimer’s. Only those with early or mild disease will be eligible for the new drug, and an even smaller subset will likely undergo the multi-step process required to get a prescription.   

The FDA approved Kisunla, known chemically as donanemab, based on an 18-month study. The study showed that patients receiving the treatment experienced about 22 percent slower decline in memory and cognitive ability compared to those given a placebo. 

The main safety issue associated with the drug is brain swelling and bleeding, common to all plaque-targeting drugs. Lilly's study reported slightly higher rates of these issues, including 20 percent of patients experiencing microbleeds, compared to Leqembi.  

However, the two drugs were tested in different patient types, making direct comparisons challenging.   

Kisunla’s once-a-month infusion schedule contrasts with Leqembi’s twice-a-month regimen, potentially easing the burden on caregivers. Schindler noted, “Certainly getting an infusion once a month is more appealing than getting it every two weeks.” 

An advantage of Lilly's drug is that patients can stop taking it if they respond well. In the study, patients discontinued Kisunla once their brain plaque reached nearly undetectable levels, with almost half achieving this within a year.  

This could reduce long-term costs and safety risks, although it remains unclear when patients might need to resume infusions.   

Logistical hurdles, spotty insurance coverage, and financial concerns have slowed the rollout of Leqembi, co-marketed by Eisai and US partner Biogen. Many smaller hospitals and health systems are not yet equipped to prescribe the new plaque-targeting Alzheimer's drugs.   

Doctors need to confirm that dementia patients have the brain plaque targeted by these drugs. They must then locate a drug infusion centre for therapy and train nurses and staff to perform repeated scans for brain swelling or bleeding.  

Mark Mintun, head of Lilly’s neuroscience division, explained, “Those are all things a physician has to have set up. Until they get used to them, a patient who comes into their office will not be offered this therapy.”