FDA has approved a new Alzheimer’s drug called Aduhelm that targets the cause of the disease rather than the symptoms.
Alzheimer’s is a progressive neurological condition that causes impaired memory, cognition, and behavioural problems. Although the exact mechanism is unclear, scientists believe an accumulation of amyloid plaques and tau proteins within the brain might be to blame. These brain proteins can cause atrophy of the brain cells and destruction of the neurons. Current treatment options only work on slowing down the progression of symptoms. However, a new Alzheimer’s drug promises to treat the underlying cause of the disease.
Aducanumab, sold under the brand name Aduhelm, is a monoclonal antibody that reduces the amyloid beta plaques within the brain. On 7th June, the US Food and Drug Administration (FDA) approved Aduhelm for treatment of Alzheimer’s. It is the first Alzheimer’s drug in almost 20 years to receive an approval.
The FDA approved the drug using an accelerated approval pathway. This allows quicker approval of potentially life-saving drugs that treat a serious condition. Typically, drug approval is based on clinical trials demonstrating a positive therapeutic effect. Instead, accelerated approval is based on the use of surrogate endpoints, which require less time. These endpoints use laboratory values, radiographic images, physical sign and other measures to predict clinical benefit.
Experts Weigh In
The FDA based its approval on the results of three separate studies, involving more than 3,000 patients.
The three clinical trials tested the drug on Alzheimer’s patients in a randomized, placebo-controlled setting. The surrogate endpoint was a reduction of amyloid beta plaques in the brain. This was measured using positron emission tomography (PET) imaging. Two of the Phase III trials revealed a significant reduction of the plaques within the brains of patients who received Aduhelm. Whereas the control group saw no reduction. Although these results support the accelerated approval of the new Alzheimer’s drug, experts are divided over the drug’s effectivity.
Notably, in March 2019 both of the phase III studies mentioned in FDA’s statement came to a halt. The suspension was a result of the trial’s analysis revealing the drug as ineffective at improving cognition or memory in patients. However, later that year the drug manufacturer, Biogen, revealed that higher doses of Aduhelm slowed down cognitive decline in Alzheimer’s patients. The contradicting results of two identical trials cast doubts on FDA’s decision to approve the drug.
Although Aduhelm has received an accelerated approval, a Phase IV trial is still left. If Biogen fails to demonstrate the drug’s clinical benefit in a randomized, controlled trial, the FDA can withdraw its approval.
Source: The US Food and Drug Administration (FDA)