Broader coverage for Eisai/Biogen’s Leqembi follows traditional FDA approval

On 6 July, Eisai and Biogen announced that the FDA approved the supplemental biologics licence application (sBLA) for Leqembi (lecanemab), thereby granting traditional full approval of the anti-amyloid beta (Aβ) monoclonal antibody (mAb) for the treatment of mild Alzheimer’s disease (AD) and mild cognitive impairment (MCI). While the accelerated approval of Leqembi, granted by the FDA on 6 January, was based on Phase II data (NCT01767311), full approval was based on data from the Phase III Clarity AD trial (NCT03887455). Leqembi-treated patients demonstrated a reduced clinical decline of 27% compared with placebo-treated patients after 18 months in Clarity AD, as measured by the primary endpoint, Clinical Dementia Rating-Sum of Boxes (CDR-SB).

The full approval for Leqembi is a pivotal moment for the AD market as the drug will become the first widely available disease-modifying therapy (DMT) for AD. Despite the drug receiving accelerated approval from the FDA in January 2023, the uptake of Leqembi has been severely limited by restricted Medicare coverage. However, upon receiving full approval, the decision by the US Centers for Medicare and Medicaid Services (CMS) to limit coverage to patients in clinical trials has been revoked, allowing for much broader coverage and significantly greater access to the drug. Based on its position as a first-to-market, widely available DMT, Leqembi is expected to become the top-selling AD drug by 2030. GlobalData forecasts that Leqembi could generate global (8MM: US, France, Germany, Italy, Spain, UK, Japan, and China) sales of approximately $3.5bn in 2030. In contrast, the CMS restriction still applies to Biogen’s Aduhelm (aducanumab), which was approved by the FDA in 2021 based on the surrogate endpoint of Aβ clearance, as it failed to demonstrate significant clinical effect in its clinical trials, and as such has continued to stymie uptake of the drug.

The decision from the CMS to now cover Leqembi fully is good news for Eli Lilly’s donanemab. This anti-Aβ mAb is expected to be the biggest competitor for Leqembi and the company will be targeting full approval for donanemab following the read-out of positive Phase III results in May this year. Donanemab demonstrated a reduced clinical decline of 35% compared with placebo at 18 months of treatment in TRAILBLAZER-ALZ 2 (NCT04437511), as measured by the primary endpoint, integrated Alzheimer’s Disease Rating Scale (iADRS). While Leqembi does have the advantage of reaching the market before donanemab, an important competitive advantage for donanemab would be its once-monthly dosing schedule compared with once every two weeks for Leqembi. GlobalData forecasts that donanemab could generate global (8MM) sales of approximately $2.0bn in 2030.