1st Patient Dosed in Phase 2a Trial of Annexon’s Antibody Therapy for Huntington’s

The first participant was dosed in a Phase 2a clinical trial testing Annexon’s investigational therapy ANX005 as a treatment for Huntington’s disease, the company announced.

The open-label study ((NCT04514367) is currently enrolling patients at three sites in Washington state and Colorado; other sites across the U.S. are not yet recruiting. More information on contacts and locations is available here.

“We are excited to advance ANX005 and look forward to initial results from our Phase 2 trial in the second half of 2021,” Sanjay Keswani, Annexon‘s chief medical officer, said in a press release.

ANX005 is a monoclonal antibody designed to inhibit C1q, the initiating molecule of the complement cascade — an important component of the innate immune system that functions primarily as a first-line host defense against infections.

Abnormal activation of the C1q protein plays a significant role in neurodegeneration by causing the loss of synapses — or the junctions between two nerve cells that allows them to communicate — chronic neuroinflammation, and eventually nerve cell death. ANX005 has the potential to prevent synaptic loss in several neurodegenerative diseases.

“Annexon targets the initiating protein of the classical complement pathway, C1q, which uniquely binds to synapses in the brain and appears to cause inappropriate synapse elimination during chronic neurodegenerative disease, such as HD,” said Beth Stevens, PhD, associate professor of neurology at Children’s Hospital Boston. “Inhibiting C1q and protecting functioning synapses may benefit patients with neurodegenerative conditions.”

The Phase 2a trial is evaluating the safety, tolerability, pharmacokinetics (the movement of drug into, through, and out of the body) and pharmacodynamics (the effects of a drug on the body) of ANX005 in individuals either with Huntington’s or at risk of the disease.

Researchers are planning to enroll a total of 24 patients (age 18 or older) who will receive an intravenous (into-the-vein) infusion of ANX005 for up to 10 weeks. Participants will receive the therapy on days one and five or six, followed by maintenance dosing every two weeks through week 10, with follow up visits on weeks 12, 16 and 24.

All participants will be contacted, either through a phone call or in a clinic visit, six months after the study is completed.

The experimental therapy has also been tested in a Phase 1b trial for Guillain-Barré syndrome, a rare autoimmune disorder that attacks the peripheral nervous system, for which it has also been granted fast track and orphan drug designations by the U.S. Food and Drug Administration.