Ionis Pharmaceuticals
Ionis Pharmaceuticals
One-line summary: Antisense-oligonucleotide (ASO) platform biotech (NASDAQ: IONS); tracked here as the modality on the wrong side of two 2026 readouts — the diranersen tau miss (with Biogen) and the eplontersen ATTR-CM null (with AstraZeneca) — both read by the panel as ASO tolerability/delivery limits.
What it is
Ionis is the pioneer of antisense-oligonucleotide drugs. ASOs are typically delivered intrathecally in CNS and carry a recurring tolerability signal that shows up as narrow therapeutic windows and dose-response oddities. Ionis partners its assets widely (Biogen on CNS, AstraZeneca on cardiometabolic).
Why it matters to stock-market
Ionis is the common thread in the 2026 "ASOs keep disappointing" pattern — it partnered both diranersen (tau, with biogen) and eplontersen (ATTR-CM, with astrazeneca). Its ASO modality is the negative in both biogen-tau-failure-to-brain-shuttle-rerate (favors IV brain-shuttle rivals) and eplontersen-failure-to-alnylam-silencer-consolidation (favors siRNA silencers).
Key facts
- Diranersen (tau, w/ Biogen): intrathecal ASO; Ph2 primary miss + inverted dose response read as ASO tolerability. Ionis viewed negatively vs IV/subQ siRNA alternatives (Arrowhead, Alnylam). From 2026-07-17-podcast-biotech-hangout-episode-189-july-17-2026.
- Eplontersen (ATTR-CM, w/ AstraZeneca): total null on top of background tafamidis (no efficacy, no CV-biomarker effect) — see eplontersen-failure-to-alnylam-silencer-consolidation. john-maraganore cites "the Eplan Turin fail in cardio transform" as an ASO-tolerability example on 2026-07-17-podcast-biotech-hangout-episode-189-july-17-2026.
Open questions
- Is the recurring ASO shortfall a modality ceiling (bearish IONS structurally) or asset-specific? The tau vs TTR reads point to modality.