Announcement • May 24
Biogen Inc. and Denali Therapeutics Inc. Provide Update on Phase 2b LUMA Study Of BIIB122 In Early-Stage Parkinson’s Disease Biogen Inc. and Denali Therapeutics Inc. announced topline results from the Phase 2b LUMA study evaluating BIIB122 (DNL151), an investigational small molecule inhibitor of LRRK2 (leucine-rich repeat kinase 2), in individuals with early-stage Parkinson’s disease. Results from the study show that BIIB122 did not slow the progression of Parkinson’s disease versus placebo, as measured by the primary endpoint of Time to Confirmed Worsening in the modified Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part II and III combined score. Secondary endpoints also did not show a benefit with BIIB122. Exploratory biomarker endpoints demonstrated >90% kinase inhibition of peripheral LRRK2 (phosphoserine 935) and, in a cerebrospinal fluid (CSF) sub-study, up to approximately 30% reduction observed in a biomarker of LRRK2 activity (phosphorylated Rab10). Expected levels of BIIB122 in the blood and CSF were sustained across the study. BIIB122 was generally well tolerated with an acceptable safety profile. Based on these results, Biogen and Denali will discontinue further development of BIIB122 in idiopathic Parkinson’s disease. Denali will continue to independently conduct the Phase 2a BEACON study evaluating the small molecule inhibitor in carriers of a pathogenic LRRK2 variant. LUMA was a Phase 2b multi-center, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of BIIB122 compared to placebo in 648 people with early-stage Parkinson’s disease between the ages of 30 and 80. Participants received BIIB122 or placebo for a minimum of 48 weeks and up to 144 weeks. The study included individuals with early-stage Parkinson’s disease with or without a pathogenic LRRK2 variant. The LUMA study was designed to evaluate the potential of LRRK2 inhibition to address the underlying biology of Parkinson’s disease. The global Phase 2a BEACON study is designed to assess safety, pharmacokinetics and biomarkers of lysosomal pathway engagement, which will inform the biomarker profile in LRRK2 pathogenic variant carriers and the impact of LRRK2 inhibition. Data from the BEACON study is anticipated in the first half of 2027. The BEACON study is being operationalized by Denali and funded under a Collaboration and Development Funding Agreement between Denali and a third party. Biogen and Denali will share detailed findings from the LUMA study at an upcoming scientific conference to contribute to the broader understanding of Parkinson’s disease and LRRK2 biology. Announcement • May 15
Biogen Announces Topline Results from Phase 2 Celia Study of Diranersen (Biib080) Biogen announced compelling topline results from the Phase 2 CELIA study evaluating diranersen (BIIB080), an investigational antisense oligonucleotide (ASO) therapy targeting tau, in individuals with early Alzheimer’s disease. CELIA did not meet its primary endpoint assessing dose response; based on the strength of the biomarker and efficacy data, Biogen plans to advance diranersen to registrational development. Robust reductions in tau pathology were observed across all studied doses, with results generally consistent with those observed in the Phase 1b study. Pre-specified analyses of cognitive endpoints demonstrated slowing of clinical decline across all studied doses, particularly at the lowest dose. The safety and tolerability profile of diranersen was generally consistent with the Phase 1b study. CELIA is an 18-month Phase 2 randomized, placebo-controlled, dose-ranging study evaluating diranersen, a tau-targeting antisense oligonucleotide (ASO). Pre-specified analyses of cognitive endpoints demonstrated slowing of clinical decline across all studied doses, particularly in participants receiving the lowest dose of diranersen, 60 mg administered every 24 weeks. Diranersen also demonstrated robust reductions in both cerebrospinal fluid (CSF) tau and tau pathology, as measured by positron emission tomography (PET), across all studied doses, with reductions maintained throughout the dosing period. CELIA did not meet its primary endpoint assessing dose response for change from baseline on the Clinical Dementia Rating–Sum of Boxes (CDR-SB) at Week 76. The safety and tolerability profile of diranersen across all studied doses was generally consistent with the Phase 1b study and the known profile of diranersen to date. The incidence of adverse events (AEs) was comparable across dose groups, with a higher incidence of serious adverse events (SAEs) observed at the highest dose studied. CELIA is a pioneering study evaluating diranersen, a first-in-class investigational ASO designed to reduce the production of tau protein at its source in early Alzheimer’s disease. While tau plays an important role in the normal function of brain cells, in Alzheimer’s disease abnormal tau can accumulate and form intracellular tangles that contribute to neurodegeneration and cognitive decline. Unlike many investigational approaches that have focused on targeting extracellular tau, diranersen is designed to reduce both extracellular and intracellular tau. Diranersen (BIIB080) is an investigational antisense oligonucleotide (ASO) therapy designed to target microtubule-associated protein tau (MAPT) mRNA to reduce the production of tau protein. Abnormal accumulation of tau in the brain is a hallmark of Alzheimer’s disease associated with neurodegeneration and cognitive decline. Diranersen is being investigated as a potential treatment for early Alzheimer’s disease. In 2025, the U.S. Food and Drug Administration (FDA) granted Fast Track designation to diranersen for the treatment of Alzheimer’s disease. In December 2019, Biogen exercised a license option with Ionis Pharmaceuticals and obtained a worldwide, exclusive, royalty-bearing license to develop and commercialize diranersen. Diranersen was discovered by Ionis. CELIA is a global Phase 2 randomized, double-blind, placebo-controlled, dose-ranging study evaluating the efficacy, safety and tolerability of diranersen in individuals with early Alzheimer’s disease. The study enrolled 416 participants with mild cognitive impairment due to Alzheimer’s disease or mild Alzheimer’s disease dementia. All participants enrolled in CELIA had not previously received anti-amyloid therapy. The study evaluated three doses of diranersen administered intrathecally over a 76-week placebo-controlled treatment period: 60 mg every 24 weeks, 115 mg every 24 weeks, and 115 mg every 12 weeks. The primary endpoint of CELIA was assessment of dose response for change from baseline on the Clinical Dementia Rating–Sum of Boxes (CDR-SB) at Week 76. Secondary and exploratory endpoints included additional clinical, biomarker and imaging measures, including cerebrospinal fluid tau biomarkers and tau positron emission tomography (PET). An ongoing long-term extension (LTE) study is continuing to evaluate the long-term safety, tolerability and durability of diranersen in early Alzheimer’s disease. Announcement • May 11
Eisai Co., Ltd. and Biogen Inc. Update on Fda Priority Review of Leqembi Iqlik (Lecanemab-Irmb) Subcutaneous Injection as A Starting Dose for Early Alzheimer's Disease Eisai Co., Ltd. and Biogen Inc. announced that the U.S. Food and Drug Administration (FDA) has extended the review period by three months for the supplemental Biologics License Application (sBLA) for a once-weekly lecanemab-irmb subcutaneous injection (U.S. brand name: LEQEMBI IQLIK) as a starting dose for the treatment of early Alzheimer's disease. The new Prescription Drug User Fee Act (PDUFA) action date is August 24, 2026. As part of the ongoing review process, the agency requested additional information and has determined that it constituted a major amendment to the sBLA, extending the PDUFA date to allow sufficient time for a full review of the additional materials. The FDA has not raised any concerns to date regarding the approvability of LEQEMBI IQLIK as a starting dose. Eisai and Biogen believe that the comprehensive clinical data package evaluating subcutaneous administration of LEQEMBI across multiple studies and dosing regimens strongly supports the potential use of LEQEMBI IQLIK for initiation therapy, following FDA approval of the subcutaneous maintenance dosing regimen on August 26, 2025. LEQEMBI has been approved by more than 50 regulatory authorities worldwide, reflecting broad regulatory confidence in LEQEMBI as a treatment option for early Alzheimer's disease. LEQEMBI is indicated for the treatment of Alzheimer's disease (AD). Treatment with LEQEMBI should be initiated in patients with mild cognitive impairment (MCI) or mild dementia stage of disease, the population in which treatment was initiated in clinical trials. LEQEMBI (lecanemab-irmb) is available: Intravenous infusion: 100 mg/mL; Subcutaneous injection: 200 mg/mL. Lecanemab is the result of a strategic research alliance between Eisai and BioArctic. It is a humanized immunoglobulin gamma (IgG1) monoclonal antibody directed against aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aß). Lecanemab has been approved in 53 countries and regions including Japan, the United States, China, Europe, South Korea, Taiwan, and Saudi Arabia, and is under regulatory review in 6 countries. Following the initial phase with treatment every two weeks for 18 months, intravenous (IV) maintenance dosing with treatment every four weeks was approved in 7 countries including the U.S., China, the UK, and others, and applications have been filed in 12 countries and regions. The U.S. FDA approved Eisai's Biologics License Application (BLA) for subcutaneous maintenance dosing with LEQEMBI IQLIK in August 2025. In November 2025, an application for a subcutaneous injectable formulation in Japan was submitted. In January 2026, the Biologics License Application (BLA) for the subcutaneous formulation was accepted in China. In December 2025, lecanemab (IV) has been included in the "Commercial Insurance Innovative Drug List", recently introduced by the National Healthcare Security Administration (NHSA) of China. Since July 2020, the Phase 3 clinical study (AHEAD 3-45) for individuals with preclinical AD, meaning they are clinically normal and have intermediate or elevated levels of amyloid in their brains, is ongoing. Since January 2022, the Tau NexGen clinical study for Dominantly Inherited AD (DIAD), that is conducted by Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU), led by Washington University School of Medicine in St. Louis, is ongoing and includes lecanemab as the backbone anti-amyloid therapy. 
