Market reactionShares fell 10% on Nov 5.
Annexon is a clinical-stage company developing complement C1q inhibitors, led by tanruprubart for Guillain-Barré syndrome and vonaprument for geographic atrophy; none are approved.
Annexon's case rests on tanruprubart, an antibody that blocks C1q, for Guillain-Barré syndrome, a rapidly paralyzing nerve disorder, where its placebo-controlled Phase 3 met its primary endpoint. The European application is under EMA review, and Annexon plans a U.S. BLA in Q4 2026 supported by the FORWARD study of U.S. and European patients. The Phase 3 ARCHER II of vonaprument in geographic atrophy reports in Q4 2026, and Annexon expects runway into 2028.
Thesis checklist
0 risks need attention
Why it is in this state
The evidence, what would weaken it and the source filing
Why it is in this state
The evidence, what would weaken it and the source filing
Why it is in this state
The evidence, what would weaken it and the source filing
Next decision point
Tests: The tanruprubart BLA is submitted and accepted
Does Annexon file a BLA that FDA accepts for review?
Strong, inconclusive and weak outcomes
What to look for in the result and how each would move the checklist
Price and material events
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Annexon plans to file tanruprubart's BLA for Guillain-Barré syndrome in Q4 2026 while EMA reviews it; vonaprument's Phase 3 in GA reads out the same quarter
GBS therapy racing a dual regulatory clock: MAA under EMA review and a BLA planned for Q4 2026, but approvability hinges on whether Western FORWARD data satisfies FDA generalizability concerns
About this history: every entry shows when the Thesis moved and what it said. The reasoning behind each move (the evidence, the analysis and the source filing) and the earnings write-ups are part of a subscription.
Dates, trials and completed outcomes are open to everyone. What each upcoming milestone hinges on is part of a subscription.
Disease areas: Eye diseases, Kidney diseases, Neuromuscular diseases, Neurology and pain, Blood disorders
Catalyst calendar · Upcoming FDA decisions · Thesis changes
Competitive landscape
17 peers tracked
Cash: Market-data provider estimate; measurement period unavailable.
Debt: Market-data provider estimate; a complete comparable filing balance is unavailable.
Quarterly burn: Estimated from trailing free cash flow; measurement period unavailable.
Net cash and estimated runway require verified matching measurement periods. Missing debt components are not assumed to be zero.
Runway: No underlying guidance available.