Annexon’s late-stage Guillain-Barré syndrome trial has hit its primary endpoint and laid the foundation for a filing for approval next year, the company said Tuesday.
Annexon said Tuesday a Phase III trial in the neurological disease Guillain-Barré syndrome met its primary endpoint, positioning the biotech to file for FDA approval next year.
The study randomized 241 people with Guillain-Barré syndrome (GBS), a rare, serious disorder of the peripheral nerves, to receive one of two doses of the anti-C1Q antibody ANX005 or placebo. After eight weeks, participants who received the lower ANX005 dose experienced statistically significant improvements on the GBS disability score, causing the study to hit its primary endpoint.
The score assesses the functional status of people with GBS, for example by differentiating between patients who need assisted ventilation at least part of the day and those who are able to walk across an open space with help. Annexon linked the lower dose to a 2.4-fold improvement on the GBS scale.
Annexon also reported improvements in muscle strength and reductions in days on artificial ventilation, two of the trial’s secondary endpoints. David Cornblath, professor emeritus of neurology, Johns Hopkins University School of Medicine, said in a statement that walking independently and moving off ventilators “are paramount to getting patients back to normal activities of daily living.”
The biotech focused its top-line analysis on the lower dose. The higher dose was statistically no better than placebo on the primary endpoint, although Annexon said it outperformed the control on multiple measures.
On a conference call to discuss the results, Jamie Dananberg, chief medical officer at Annexon, said the divergence between the two doses “suggest that for most patients the prolonged inhibition of C1q with the 75 milligram per kilogram dose is beyond the therapeutic window and limits C1q-mediated tissue repair.”
Annexon plans to file for FDA approval in the first half of next year. The filing is planned for around when the biotech expects to have real-world evidence (RWE) comparability data. Annexon only activated sites in Bangladesh and the Philippines for the Phase III trial, a decision it attributed to the limited access to standard of care intravenous immunoglobulin, and is generating RWE in the West to support filings.
The FDA can approve medicines based solely on foreign data if the results are applicable to the U.S. population, the studies have been performed by clinical investigators of recognized competence and the data may be considered valid without an on-site inspection. However, the agency has rejected filings that relied on foreign data in recent years.
Nick Paul Taylor is a freelance pharmaceutical and biotech writer based in London. He can be reached on LinkedIn.
