Biogen Ready to Catch Alzheimer’s Patients Transitioning Off Lilly’s Kisunla

Why It Matters

The transition creates a sizable market opportunity for Biogen, potentially reshaping the competitive landscape of disease‑modifying Alzheimer’s treatments and boosting its revenue diversification.

Key Takeaways

• Kisunla patients face 18‑month stop, may switch to Leqembi
• Leqembi sales rose 74% YoY to $168 M in Q1 2026
• Biogen seeks FDA nod for Iqlik induction by May 24
• Leqembi’s at‑home dosing could erode Kisunla’s advantage
• Biogen eyes Alzheimer’s growth amid MS generic pressure

Pulse Analysis

The Alzheimer’s therapeutic arena has rapidly evolved since the FDA’s 2023 approval of Leqembi, the first disease‑modifying antibody to gain market traction. Unlike Eli Lilly’s Kisunla, which is administered until amyloid clearance is confirmed via PET scans, Leqembi offers indefinite dosing and, with the upcoming subcutaneous Iqlik formulation, the promise of at‑home administration. This dosing flexibility addresses a key barrier for patients and providers—frequent infusion visits—and positions Leqembi as a more convenient long‑term solution.

Biogen’s strategy hinges on converting the cohort of Kisunla patients who must discontinue therapy after the 18‑month window. By promoting Leqembi as a seamless maintenance alternative, the company can capture a pipeline of high‑need patients already familiar with antibody therapy. The pending FDA decision on Iqlik’s induction use, slated for May 24, could further erode Kisunla’s competitive edge by eliminating the need for an initial infusion phase. Coupled with Leqembi’s robust Q1 2026 performance—$168 million globally, $86 million in the U.S., and a 12% beat of consensus—Biogen is poised to translate clinical preference into measurable revenue growth.

Beyond immediate sales, the shift underscores broader industry dynamics. Investors are watching Biogen’s Alzheimer’s push as a counterbalance to mounting generic pressure on its multiple‑sclerosis portfolio. Successful adoption of Leqembi could accelerate consolidation among amyloid‑targeting therapies and spur further innovation in delivery mechanisms. For payers, the move toward subcutaneous, at‑home dosing may ease reimbursement complexities and improve adherence, ultimately influencing long‑term cost‑effectiveness assessments across the Alzheimer’s care continuum.