Biogen Announces Positive Phase 2 Results for Diranersen
Biogen Inc. (NASDAQ:BIIB) reported that its shares increased roughly 2% on Tuesday following the presentation of Phase 2 CELIA study data at the Alzheimer’s Association International Conference. The investigational Alzheimer’s treatment, diranersen, an antisense oligonucleotide targeting MAPT mRNA to reduce all tau isoforms, demonstrated efficacy across all studied doses over an 18‑month period.
The 60 mg dose produced the strongest clinical response, slowing decline on the ADAS‑Cog13 cognitive test by 42%, on the MMSE by 50%, and on the CDR‑SB functional scale by 26% compared with placebo. Diranersen also achieved the first tau‑directed reductions in both cerebrospinal fluid total tau (mean 50‑65% decrease) and brain tau pathology measured by PET across every dose evaluated.
The CELIA trial enrolled 416 participants with early Alzheimer’s disease and administered three intrathecal doses of diranersen over 18 months. Although the study did not meet its primary endpoint of a dose‑response relationship on CDR‑SB at 18 months, the drug was generally well tolerated. Most adverse events were mild or moderate, with the most frequent being procedural pain, post‑lumbar puncture syndrome, and confusional state. More than 90% of participants who completed the placebo‑controlled phase elected to continue into the extension study.
Based on these findings, Biogen intends to advance diranersen into Phase 3 development. The U.S. Food and Drug Administration previously granted Fast Track designation to diranersen for Alzheimer’s disease in 2025.
This article was generated with AI assistance and reviewed by an editor.