Eisai's Leqembi Shows Mixed Performance, Eyes Subcutaneous Formulation

Eisai's Alzheimer's therapy Leqembi, developed in partnership with Biogen, is making steady progress towards its fiscal year 2024 revenue goal of ¥42.5 billion ($279 million), despite underwhelming sales in the United States. The company's latest earnings announcement reveals a complex landscape for the anti-amyloid antibody, with international markets driving growth while U.S. uptake lags behind expectations.

Global Sales Performance

In the third quarter of Eisai's 2024 fiscal year (October to December 2024), Leqembi generated approximately ¥13.3 billion ($87.4 million) in global sales. The U.S. market contributed ¥7.7 billion ($51 million), representing a 30% quarter-on-quarter growth. However, the drug's performance was particularly strong in international markets, with Japan seeing a nearly 50% surge to ¥4.1 billion ($27 million), and Chinese and other international markets jumping 33% to ¥1.5 billion ($9.9 million).

Analysts at Jefferies characterized Leqembi's U.S. performance as "steady" and "expected," while highlighting the overseas sales as the primary driver of Eisai's growth. The drug's international success is offsetting the slower uptake in the U.S. market, which has been a persistent challenge since its launch.

U.S. Market Developments

Despite the slower-than-anticipated sales in the U.S., there are signs of improvement. Eisai reports that approximately 13,500 patients are currently on Leqembi, surpassing analysts' expectations. The number of prescribing physicians has grown to around 3,000, while 1,200 medical institutions are now purchasing the drug, representing 20% and 12% quarter-on-quarter growth, respectively.

The company also noted a 45% increase in amyloid-beta PET testing compared to the previous quarter, suggesting an expansion in the capacity to identify and accommodate potentially eligible patients. Eisai anticipates that the recent FDA approval of Leqembi's once-monthly maintenance regimen will further accelerate its uptake in the U.S. market.

Future Prospects and Subcutaneous Formulation

Eisai is actively working on a subcutaneous formulation of Leqembi, which could significantly reduce the burden on healthcare professionals and patients by allowing at-home administration and minimizing the number of required visits. The FDA has accepted the application for subcutaneous Leqembi for maintenance dosing, with a target action date of August 31, 2025.

The company plans to file its subcutaneous application for induction dosing after this verdict, aiming for approval later this year or early next year. This development could potentially address some of the challenges faced in the U.S. market and improve the drug's overall accessibility and convenience for patients.