Biogen finds Alzheimer’s path for tau ASO despite mixed data

Biogen cannot yet explain why the low dose of its tau-targeting therapy diranersen outperformed the high dose in a Phase II Alzheimer’s trial, but the company says it saw enough — across target engagement, cognitive signal and tolerability — to advance the low dose into Phase III.

The results of the CELIA study were mixed. Diranersen did not meet its primary endpoint of Clinical Dementia Rating–Sum of Boxes (CDR-SB) at week 76. But across all three doses tested, Biogen Inc. (NASDAQ:BIIB) said the antisense oligonucleotide (ASO) produced “robust” reductions in both cerebrospinal fluid tau and tau pathology in the brain as measured by PET imaging. Prespecified analyses of cognitive endpoints showed slowing of clinical decline, with the strongest effect at the lowest dose of 60 mg every 24 weeks...