about the study 

This is a multicentre, open label (placebo is not expected: all participants will receive the experimental drug) study aimed at understanding a potential biological effect of ANX005.

The study aims, with a phase 2/a, to verify the biological effect and tolerability (not the efficacy) after 10 weeks of treatment in a very limited number of patients with Huntington's disease.

about the experimental drug anx005

ANX005 monoclonal antibody intended to treat patients with antibody-mediated autoimmune and complement-mediated neurodegenerative disorders. This novel therapy is formulated for intra venous administration and it is designed to inhibit C1q and the entire classical complement pathway.

Aberrant activation of C1q plays a significant role in the neurodegenerative process by causing synapse loss, chronic neuroinflammation and eventual neuronal death. 

The goal is to slow down the course of the disease by inhibiting the harmful activity of the C1q protein. Connection protection is a strategy to counteract synapse loss, which leads to neurodegeneration and cognitive impairment. Inhibition of C1q and protection of synapses may benefit patients with neurodegenerative conditions.

ANX005 has already been tested in phase 1/b in Guillain-Barré Syndrome (GBS). In this placebo controlled, dose escalation trial in 31 patients, ANX005 was well-tolerated at all dose levels. An intra venous infusion of ANX005 resulted in full and prolonged C1q engagement and classical cascade inhibition, measured in the blood and cerebrospinal fluid (CSF). Treated patients showed significantly reduced levels of neurofilament light chain (NfL), a well-accepted marker of nerve damage in neurodegenerative disease that has been shown to correlate with disease severity and clinical outcomes. In Huntington's disease, NfL levels correlate with the severity of the disease.

Treated patients also demonstrated consistent positive trends across key GBS outcome measures, including an early impact on muscle strength, which correlates with prognosis for long-term functional recovery. These observations encouraged the launch of a preliminary study with ANX005 in patients with Huntington's disease. ANX005 has received both Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration for the treatment of GBS.

Study sites 

The study is carried out in 8 study sites in the United States, of which only three have started recruiting to date *:

  • Birmingham, Alabama,
  • Sacramento, California
  • Englewood, Colorado *
  •  Washington, District of Columbia
  • Durham, North Carolina
  • Cincinnati, Ohio
  • Kirkland, Washington *
  • Spokane, Washington *

Treatment period

From 17 August 2020 to 31 December 2021

Number of Participants

24, all of whom belong to a single drug assignment group (open-label study)


ANX005 will be administered intravenously for up to 10 weeks.

Participants will receive induction dosing on days 1 and 5 or 6, followed by maintenance dosing every 2 weeks through week 10, with follow-up visits at weeks 12, 16, and 24.


To assess safety and tolerability in individuals with - or at risk of - Huntington's disease

Inclusion criteria:

  • Age 18 ≥ years
  • Diagnosis of HD at early stage or at risk, with CAP score> 400 and IS-UHDRS score ≥ 80%
  • Able to walk independently and self-sufficient in carrying out daily activities (eg eating, dressing, washing). 
  • Stable concomitant drug therapy.

Official Pipeline

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