Ionis Pharmaceuticals: IONS: Thoughts on the Full Tau Data

Research evidence excerpt

Ionis Pharmaceuticals: IONS: Thoughts on the Full Tau Data

USA | Biotechnology

Ionis Pharmaceuticals EquityJulyResearch14, 2026

COMPANY UPDATEIONS: Thoughts on the Full Tau Data

BIIB/IONS CELIA Ph2 data was given at AAIC today. As prev top-lined (HERE), RATING BUY

Diranersen missed primary endpt of dose response for CDR-SB changes at PRICE $56.75^

wk76. While all dose cohorts showed reductions in Tau pathology (CSF tau PRICE TARGET | % TO PT $90.00 | +59%

& Tau PET), only the lowest 60mg Q24W cohort achieved meaningful clinical 52W HIGH-LOW $86.74 - $40.03

efficacy comparable to mAbs (26% vs 23-27% slowing w/ Aß agents). Overall, FLOAT (%) | ADV MM (USD) 100.0% | 173.61

Qs remain on the clinical translatability of the MOA & optimal dose heading into MARKET CAP $9.2B

the planned Ph3 TICKER IONS

^Prior trading day's closing price unless otherwise

noted.

Bottom Line: BIIB/IONS gave the full data from Ph2 CELIA study of Diranersen (an ASO targeting

Tau) in pts w/ early Alzheimer's Disease. As a reminder, BIIB prev. top-lined that the study didn't

meet its primary endpt of dose response in CDR-SB change from BL to wk76 (HERE). After talking FY (Dec) CHANGE TO JEFe JEF vs CONS

to IONS post the top-line data, we got the sense that there was a correlation between cognitive 2025 2026 2025 2026

benefit and tau reduction + we hoped for a clinically meaningful trend across all dose cohorts & no REV NA NA +26% +1%

inverse dose response. However, the full data showed only the lowest-dose cohort (60mg Q24W) EPS NA NA NA NA

achieved efficacy (26% CDR-SB effect) comparable to Aβ agents (23-27% slowing).

Our take? The full data was underwhelming, and left us with more questions than answers re:

the potential of Tau-targeting agents succeeding in a larger Ph3 study for Alzheimer's.