Biogen Inc Stock Price, News & Analysis

Biogen (NASDAQ:BIIB) and Eisai presented CTAD 2025 data showing continued LEQEMBI (lecanemab-irmb) maintenance treatment in early Alzheimer's disease may delay progression.

Key findings: time savings vs untreated ADNI decline — MCI to mild AD: overall +2.5 years, low-amyloid subgroup +6.0 years; MCI to moderate AD: overall +3.5 years, low-amyloid subgroup +8.3 years. A subcutaneous (SC) initiation program showed bioequivalence to IV (exposure ratio 104%, 90% CI 99.1%–109%) and low immunogenicity (ADA 1.4%).

Regulatory status: SC maintenance approved in US Aug 2025; sBLA rolling complete Nov 2025; Japan submission Nov 2025.

Biogen (Nasdaq: BIIB) and Eisai presented CTAD 2025 data showing that lecanemab (LEQEMBI) binds Aβ protofibrils (PF) measurable in CSF, supporting target engagement and a pharmacodynamic effect. In a Clarity AD CSF sub-cohort (n=410) total CSF PF rose +59% at 12 months with lecanemab vs +19% with placebo (difference p=0.0126). The treatment-associated PF mobilization correlated with a loss of the placebo correlation between PF changes and neurodegeneration/tau biomarkers, suggesting reduced PF-driven neurotoxicity. Safety data reiterated ARIA and ICH risks and recommended MRI monitoring and ApoE ε4 testing prior to treatment.

Stoke Therapeutics and Biogen (Nasdaq: BIIB) will present new clinical and EEG analyses for zorevunersen at the 2025 American Epilepsy Society Annual Meeting (Dec 5–9, Atlanta).

Presentations report up to four years of data from Phase 1/2a and ongoing open‑label extension (OLE) studies, including propensity‑weighted analyses and EEG findings in patients with Dravet syndrome. Zorevunersen is also being evaluated in the global pivotal Phase 3 EMPEROR study in children and adolescents with Dravet syndrome.

Sessions include one oral presentation (Dec 5) and multiple posters (Dec 6–8) covering seizure outcomes, seizure‑free days, quality of life, overall functioning, and electrophysiological EEG changes linked to seizure reductions.

Biogen (Nasdaq: BIIB) and Eisai announced completion of the rolling submission of an sBLA to the U.S. FDA on Nov 25, 2025 seeking approval of LEQEMBI IQLIK (lecanemab-irmb) as a 500 mg once-weekly subcutaneous starting dose after the FDA granted Fast Track Status. Company data show the 500 mg SC autoinjector (two 250 mg injections) achieved equivalent exposure to IV dosing every two weeks with similar clinical and biomarker effects and a safety profile comparable to IV administration (~<2% systemic injection/infusion reactions). If approved, IQLIK would allow at-home initiation and maintenance dosing and could reduce IV infusion resource needs; FDA will set a PDUFA action date upon sBLA acceptance.

Biogen (Nasdaq: BIIB) and Dayra Therapeutics announced a research collaboration on November 24, 2025 to discover and develop oral macrocyclic peptides for priority immunological targets.

Key terms include a $50 million upfront payment to Dayra, program-level option and milestone payments, and Biogen leading further development, manufacturing, and potential commercialization. Biogen will record the upfront as an Acquired In-Process R&D expense in Q4 2025, and the amount was included in Biogen’s updated 2025 guidance issued October 30, 2025.

Biogen (Nasdaq: BIIB) will present new clinical and real-world lecanemab (LEQEMBI) data at the 18th Clinical Trials on Alzheimer’s Disease (CTAD) conference, Dec 1–4, 2025, in San Diego.

Highlights include subcutaneous initiation dosing safety and feasibility, evidence that continued treatment may yield additional long-term clinical benefit, an analysis estimating 10‑year time‑savings based on Phase 3 data, and interim real-world findings from a post‑marketing study in Japan and the ALZ‑NET registry. Biogen will also share biodistribution data for investigational ASO BIIB080 and research on disease‑progression measures.

Biogen (Nasdaq: BIIB) and Stoke Therapeutics published final two-year natural history data from the BUTTERFLY study in Neurology on November 14, 2025, describing disease course in children and adolescents (ages 2–18) with Dravet syndrome.

Key findings: neurodevelopment plateaued at a developmental age of ~2 years regardless of entry age, creating a widening gap versus typical development; major motor seizure frequency rose 10.6% over two years (baseline 14.3 seizures/28 days; p=0.63; n=23). Study used pre-specified adaptive and cognitive measures aligned with endpoints in the Phase 3 EMPEROR trial of zorevunersen.

Biogen (Nasdaq: BIIB) announced a positive CHMP opinion recommending approval of a high dose regimen of nusinersen for 5q spinal muscular atrophy, with a final European Commission decision expected in January 2026.

The CHMP opinion is based on the Phase 2/3 DEVOTE study: Part B (n=75) showed a mean CHOP-INTEND difference of 26.19 points (+15.1 vs -11.1; p<0.0001) and a 68% reduction in risk of death or permanent ventilation versus a matched sham group. Part C (n=38) reported a HFMSE mean increase of 1.8 points at Day 302 after switching from 12 mg. Dosing: two 50 mg loading doses 14 days apart then 28 mg every 4 months (single 50 mg loading for switchers). Safety was generally consistent with known profile; common AEs included pneumonia, COVID-19, aspiration pneumonia, and malnutrition.

Biogen (Nasdaq: BIIB) completed its acquisition of Alcyone Therapeutics on Nov 14, 2025, gaining the investigational implantable drug delivery device ThecaFlex DRx™.

ThecaFlex DRx™ is designed to reduce repeat lumbar punctures for chronic intrathecal administration and has been in development since 2019 with the PIERRE and PIERRE-PK clinical studies for nusinersen (SPINRAZA®) currently underway. Biogen plans to introduce the delivery system for SPINRAZA in early 2028, contingent on successful clinical trial completion and regulatory approval. Biogen cites the acquisition as a way to combine its biopharmaceutical capabilities with device technology to potentially improve patient experience and broaden access to therapies.