The U.S. Food and Drug Administration (FDA) is currently reviewing a novel subcutaneous version of Leqembi, a revolutionary medicine developed by Eisai Co., Ltd. and Biogen Inc. This innovative at-home administration option has the potential to improve patient care by increasing treatment accessibility and convenience. 

Leqembi, which is already approved in several countries, including the United States, Japan, and the United Kingdom, is being recognised as an important aid in reducing the progression of Alzheimer's disease. Traditionally supplied intravenously, a subcutaneous autoinjector (SC-AI) represents a possible alternative. Patients might receive medication without having to attend the hospital with a short 15-second injection, which would improve adherence and reduce carer strain.

"The ability to administer Leqembi at home could significantly improve adherence to treatment and enhance quality of life for patients and carers," Eisai told the press. 

Based on the results of the Clarity AD (Study 301) open-label extension, the FDA should ok the Biologics License Application (BLA) for Leqembi SC-AI. The medicine works by targeting protofibrils and amyloid-beta plaques, which are toxic protein accumulations in the brain that cause cognitive loss. The proposed subcutaneous maintenance regimen is likely to maintain the clinical and biomarker advantages over time. 

With a Prescription Drug User Fee Act (PDUFA) action deadline of August 31, 2025, the FDA's decision will determine whether Leqembi is the first Alzheimer's medication available for subcutaneous administration at home. 

Unlike previous medications, Leqembi uses a dual mechanism to reduce Alzheimer's progression. It continuously removes highly toxic protofibrils that cause neuronal injury while also lowering plaque accumulation. According to research, long-term treatment may extend cognitive benefits even after plaque eradication. 

Aside from its biological impact, the transition from intravenous to subcutaneous administration has substantial benefits. Eliminating the need for frequent hospital visits improves convenience, making it easier for patients to stick to their treatment regimen. The ease of using an autoinjector increases patient comfort by eliminating the anxiety and logistical issues associated with IV infusions. Additionally, this change minimises reliance on infusion centres, cutting associated medical expenses and making therapy more cost-effective. These advancements are especially important in underprivileged communities where access to healthcare institutions is limited, and they align with larger initiatives to make Alzheimer's therapy more accessible to a larger population. 

Despite its promise, Leqembi does not come without hazards. It has been shown in clinical trials to cause Amyloid-Related Imaging Abnormalities (ARIA), such as brain growth and small blood clots. Symptomatic ARIA was found in 3% of patients, whereas severe ARIA symptoms were described in 0.7% of instances. However, with proper monitoring, the majority of ARIA instances recover over time, reducing long-term concerns. Those with the ApoE ?4 genetic variation, a risk factor for Alzheimer's, were more likely to develop ARIA and required close monitoring during treatment. Given these considerations, clinicians should evaluate individual risk factors before prescribing Leqembi to ensure patient safety and maximise treatment outcomes. 

Leqembi is now undergoing regulatory evaluation in 17 countries and regions, following a positive recommendation from the European Medicines Agency. Eisai and Biogen continue to drive global development, ensuring that the medicine reaches more patients worldwide. 

"The future of Alzheimer's treatment is dependent on ongoing innovation and accessibility. Experts believe Leqembi's subcutaneous form has the potential to revolutionise how we manage this condition. 

As the FDA's August 2025 decision approaches, millions of Alzheimer's sufferers and their families anticipate what may be a watershed event in neurological healthcare.