Company profile / ANNX
Annexon is a clinical-stage biopharmaceutical company built on a single upstream target: C1q, the initiating molecule of the classical complement cascade. Vonaprument and tanruprubart are the same anti-C1q antibody deployed in two tissues — geographic atrophy (intravitreal) and Guillain-Barré syndrome (IV) — making the pipeline two shots on one biological thesis rather than two unrelated programs.
We carry a central fair value of ~$8.5–9 per share against $5.07 spot, ~70–75% upside, on a regressed ARCHER II statistical case that clears the pooled Month-15 gate ~65–70% of the time — materially better odds than the raw 5-vs-19 event count implies. Downside is supported, not open-ended: a GA failure leaves ~$2.5–3.4 per share from tanruprubart (GBS), net cash and pipeline.
The tape prices ARCHER II close to a low-probability statistical coin flip on a fragile Phase 2 signal. Our bottom-up reconstruction of that signal, regressed for winner's-curse bias, implies materially better statistical odds than the "handful of events" framing suggests.
Whether a clean, uniform ARCHER II win translates into category-maker commercial behavior (dosing to label, durable persistence) or merely share-taker economics within the existing GA paradigm — the quality of the readout, not just its statistical pass/fail, sets what GA is worth.
ARCHER II pooled Month-15 primary endpoint assessment, expected Q4 2026; if positive, the two-substudy consistency analysis follows in Q1 2027.
2 assets · 2 programs
ARCHER II can survive heavy regression of the Phase 2 GA effect — RR ~0.5–0.6 still leaves a viable Phase 3, with replicated visual functional benefit offering genuine differentiation in GA
