Batoclimab (HBM9161)

Batoclimab (also known as HBM9161, HL161, RVT-1401, or IMVT-1401) is an experimental treatment for autoimmune disorders including myasthenia gravis.

Originally developed by HanAll Biopharma, batoclimab is now being developed by Harbour Biomed which holds a license to commercialize it in Greater China (Hong Kong, Macau, and Taiwan). Immunovant (a subsidiary of Roivant) is developing batoclimab for commercialization in the U.S. and Canada.

How does batoclimab work?

Myasthenia gravis is an autoimmune disorder where the patient’s antibodies (called immunoglobulin G, IgG) that normally fight off bacteria and viruses instead attack the neuromuscular junction, or the point where nerve cells and muscle cells meet. These attacks cause a loss of signal from nerves to muscles and ultimately leads to progressive muscle weakness.

Batoclimab is a fully human monoclonal antibody (man-made using human cells) that binds to a receptor called neonatal fragment crystallizable receptor (FcRn). IgG antibodies usually bind to FcRn on the surface of cells, before entering the cells. FcRn also helps keep IgG from being broken down. When batoclimab binds to FcRn, it blocks IgG from binding to it. When IgG cannot bind to FcRN, it is degraded and the levels of IgG are reduced throughout the body. This is thought to help ease the flare-ups of myasthenia gravis.

Batoclimab in clinical trials

A Phase 1 clinical trial (NCT03917916) investigated the safety, tolerability, pharmacokinetics (movement in the body), and pharmacodynamics (effect on the body) of batoclimab in 24 healthy volunteers of Han Chinese ancestry in China. Researchers randomly assigned participants to receive a single, under-the-skin dose of 340 mg, 510 mg, or 680 mg of batoclimab or a placebo. They then monitored them for 85 days. The results showed that batoclimab was safe and resulted in a reduction in IgG levels.

Ongoing clinical trials

A Phase 2 randomized, double-blind, placebo-controlled clinical trial (NCT04346888) is recruiting adult patients with myasthenia gravis in Shanghai, China. The study aims to recruit up to 30 patients who will randomly receive 340 mg or 680 mg of batoclimab, or a placebo for six weeks. Afterwards, patients may enter an open-label extension study where they will all receive 340 mg of treatment. The study will primarily look for a change in the myasthenia gravis activities of daily living (MG-ADL) score at day 43 compared to baseline. Researchers will also record and assess changes in several other scores throughout the study. They estimate that the study will be completed in November 2021.

Another Phase 2 trial, called Ascend MG, (NCT03863080) is also investigating the effect of batoclimab in adult patients. The study aims to recruit 21 patients who will receive treatment in three groups every week for six weeks: 340 mg or 680 mg of batoclimab or a placebo. After the six weeks, all patients may continue on an open-label extension study with a 340 mg dose of batoclimabdose every other week for six weeks. The primary endpoints for this study are the number of adverse events and changes in multiple forms of IgG levels from baseline to week 7.

Researchers released topline results from 15 patients in August 2020, which showed that batoclimab was generally safe, and patients tolerated it well. IgG levels in the blood decreased by 59% in patients receiving the lower dose and by 76% in those receiving the higher dose of treatment. Patients who received the treatment also showed improvements in the MG-ADL as well as the myasthenia gravis composite scale (MGC) scores. Patients receiving treatment had an average improvement of 3.8 points on the MG-ADL score compared to a 0.6-point decline for those in the placebo group. On the MGC scale, patients who received treatment improved by 8 points on average compared to a 1.4-point worsening in those on the placebo. The trial is still recruiting participants in the U.S. and Canada and is due to conclude in December 2020.

Based on the results of this trial, Immunovant may launch a Phase 3 trial.

Other details

Researchers are also investigating batoclimab as a treatment for immune thrombocytopenia, Graves’ ophthalmopathy, neuromyelitis optica spectrum disorder, and warm autoimmune hemolytic anemia.


Last updated: Nov. 4, 2020


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