Biogen (BIIB) and Denali Therapeutics' (DNLI) experimental Parkinson's disease treatment, BIIB122, did not meet its primary and secondary endpoints in the Phase 2b LUMA study, prompting the companies to discontinue its development in idiopathic Parkinson's disease.
The companies released topline results showing that BIIB122, a small-molecule LRRK2 inhibitor, failed to slow disease progression compared with placebo in people with early-stage Parkinson's disease. The primary measure- Time to Confirmed Worsening on the MDS-UPDRS Part II and III combined score- showed no improvement, and secondary endpoints also did not demonstrate benefit.
LRRK2 is a kinase implicated in both familial and sporadic Parkinson's disease, with mutations accounting for 4-5% of familial cases and 1-2% of sporadic cases. Common variants around the gene are also recognized risk factors. LRRRK2 plays a major role in intracellular trafficking within the endolysosomal system, a pathway strongly linked to Parkinson's disease biology.
Despite the lack of clinical efficacy, exploratory biomarker data confirmed that the drug achieved more than 90% inhibition of peripheral LRRK2 activity and showed up to a 30% reduction in a cerebrospinal fluid biomarker of LRRK2 activity in a sub-study. Drug levels in blood and CSF were sustained, and BIIB122 was generally well tolerated with an acceptable safety profile.
Study Overview
The LUMA trial enrolled 648 adults aged 30 to 80 with early-stage Parkinson's disease, including individuals with and without pathogenic LRRK2 variants. Participants received BIIB122 or placebo for at least 48 weeks and up to 144 weeks in this randomized, double-blind, placebo-controlled study designed to test whether LRRK2 inhibition could address underlying disease biology.
Company Statements
Biogen's neurodegeneration clinical leader, Dr. Diana Gallagher, noted that while the results were not what the company hoped for, the data provide important information to the Parkinson's community. Denali's Chief Medical Officer, Dr. Peter Chin, emphasized that the study was a robust test of LRRK2 inhibition and that further analysis may help inform next steps for development.
What Continues
While BIIB122 will no longer be pursued for idiopathic Parkinson's disease, Denali will continue its independent Phase 2a BEACON study, which evaluates the same molecule in individuals who carry a pathogenic LRRK2 variant- a genetically defined subgroup associated with increased LRRK2 kinase activity. Data from BEACON are expected in the first half of 2027.
Broader Context
Parkinson's disease affects more than one million people in the U.S. and over 10 million globally Its complexity, diverse symptoms, and lack of reliable biomarkers make drug development particularly challenging. Lysosomal dysfunction- a failure of the cell's waste-disposal system- is considered a central pathogenic driver of Parkinson's disease, and LRRK2 remains a significant therapeutic target due to its role in this pathway.
Biogen and Denali plan to present full LUMA findings at an upcoming scientific conference to support continued research into Parkinson's disease and LRRK2 biology.
BIIB has traded between $121.05 and $205.97 over the past year. The stock closed Thursday's trading at $189.47, up 0.89%. During overnight trading, the stock was at $189.00, down 0.25%.
For comments and feedback contact: editorial@rttnews.com
Business News
May 15, 2026 15:25 ET Apart from the confirmation of Kevin Warsh as the next Fed chair, the main news on the economics front this week included key price data from the U.S. and the first quarter economic growth figures from major economies. Both consumer prices and producer costs have started to reflect the effect of supply shocks due to the Middle East conflict. In Europe, GDP data was in focus, while inflation data from China dominated the news flow in Asia.