Annexon, Inc. Reports Positive Early GBS FORWARD Study Responses

What Happened

• On August 6, 2026, Annexon, Inc. filed a Form 8-K (Item 8.01) to announce a press release reporting that the first U.S. and European patient cohort in the GBS FORWARD study showed rapid, positive clinical responses in all tanruprubart-treated patients within one week. The press release is attached as Exhibit 99.1 to the 8-K.

Key Details

• Date filed: August 6, 2026 (Form 8-K, Item 8.01).
• Study: GBS FORWARD (first U.S. and European patient cohort).
• Drug: tanruprubart — all treated patients demonstrated positive clinical responses within one week.
• Press release included as Exhibit 99.1 to the 8-K.

Why It Matters

• This filing reports a clinical development milestone: early, consistent responses in the initial cohort of a targeted study for Guillain-Barré syndrome (GBS). For investors, clinical readouts like this are material progress updates on drug development programs. The 8-K does not report financial results, regulatory approvals, or detailed patient counts or outcome metrics beyond the statements in the press release; investors should review the attached Exhibit 99.1 for full details.