Annexon soars on positive results for ANX005 in Guillain-Barré syndrome

Shares in California, USA-based autoimmune specialist Annexon (Nasdaq: ANNX) soared more than 37% in pre-market trading on Tuesday to $6.32, after it announced positive top-line results from its randomized placebo-controlled pivotal Phase III trial in patients with Guillain-Barré syndrome (GBS).

The Phase III trial met its primary endpoint, with its monoclonal antibody (MAb) ANX005 30 mg/kg achieving a highly statistically-significant 2.4-fold improvement on the GBS-disability scale (GBS-DS) at week 8 (proportional odds analysis, p = 0.0058).

ANX005 30 mg/kg treatment also demonstrated improvements versus placebo on key secondary endpoints, including early gains in muscle strength by Medical Research Council (MRC) sum score at day 8 (p <0.0001*) and at week 8 (p = 0.0351), and a median of 28 fewer days on artificial ventilation through week 26 (p = 0.0356).