CV-MG01 for myasthenia gravis
Last updated Jan. 14, 2025, by Andrea Lobo, PhD
Fact-checked by Joana Carvalho, PhD
What is CV-MG01 for myasthenia gravis?
CV-MG01, also called Myasterix, was a therapeutic vaccine being explored by Curavac as a potential treatment for myasthenia gravis (MG). Its development appears to have been halted after the company withdrew a planned Phase 2/3 clinical trial due to a lack of participating centers, which compromised timely patient recruitment.
The company is now reportedly preparing a Phase 2 efficacy trial that will assess the effects of a more potent formulation of the vaccine, called CV-MG02.
Administered as injections under the skin, or subcutaneously, CV-MG01 received orphan drug designations in Europe and the U.S. The designations provide regulatory support and financial benefits to accelerate the development and regulatory review of therapies with the potential to treat rare diseases.
Therapy snapshot
Treatment name: | CV-MG01 |
Administration: | Subcutaneous injections |
Clinical testing: | Development apparently halted following withdrawal of Phase 2/3 trial |
How does CV-MG01 work in myasthenia gravis?
MG is an autoimmune disease caused by autoantibodies that target proteins at the neuromuscular junction, the site where nerve and muscle cells communicate to coordinate voluntary movements. In most patients, autoantibodies target acetylcholine receptors (AChRs) on muscle cells.
Nerve cells normally release a neurotransmitter called acetylcholine that binds AChRs on the surface of muscle cells, triggering a muscle contraction. In MG, autoantibodies block or damage AChRs, disrupting nerve-muscle communication and causing the symptoms of muscle weakness and fatigue.
CV-MG01 is a therapeutic vaccine made up of two synthetic peptides, or short chains of amino acids, that are designed to mimic specific regions of the AChR protein. These peptides are designed to stimulate the immune system to produce specialized antibodies that can bind and neutralize anti-AChR autoantibodies, and bind to immune T-cell receptors involved in producing autoantibodies. By blocking the harmful effects of anti-AChR autoantibodies and reducing the production of new autoantibodies, CV-MG01 should be able to restore proper nerve-muscle communication and ease MG symptoms.
In preclinical studies, the peptides prevented or reduced muscle fatigue in a rat model of MG and increased the rate of disease remission in pet dogs. They also lowered the levels of anti-AChR antibodies in both animal models.
How was CV-MG01 administered in myasthenia gravis?
In clinical trials involving MG patients, CV-MG01 was given as three consecutive subcutaneous injections.
CV-MG01 in myasthenia gravis clinical trials
CV-MG01 has been tested in two clinical trials involving people with MG: a Phase 1/2 trial called CV-0002 (NCT02609022) and a Phase 2/3 study called CV-0003 (NCT03165435). Its clinical development has apparently been stopped after patient enrollment failed to be completed in the Phase 2/3 trial.
CV-0002 trial
The Phase 1/2 CV-0002 trial aimed to assess the safety and tolerability of CV-MG01, along with its ability to trigger an immunogenic response.
The study enrolled 24 patients (18 women, six men) with low to moderately severe MG, ages 24-64, who were divided into groups of eight patients, where six received the vaccine at one of two doses, and two were given a placebo. The first group received the lower dose of the vaccine, while those in the second and third groups were given the highest dose.
The study was divided into two parts: a five-month active period, where the vaccine or placebo were administered as three subcutaneous injections at week one, five, and 13, with a biweekly follow-up until week 20; and a two-year observational part, where patients were monitored to assess the treatment’s effects over time.
Interim results from the first two groups who received CV-MG01 showed both vaccine doses markedly reduced the MG Composite score, a measure of MG severity, and improved patient-reported quality of life.
The higher dose led to a greater decrease in the Quantitative MG (QMG) score, another commonly used measure of MG severity, with 66% of patients given it having a 3 point decrease in QMG, compared with 33% of those treated with the low dose, and 25% of those on a placebo. The higher dose was also more effective at prompting an immune response, even though the vaccine’s overall immunogenic response was found to be low.
Final results indicated the treatment was generally safe and no serious side effects were reported.
CV-0003 trial
The Phase 2/3 CV-0003 trial was designed with the main goal of assessing the therapy’s efficacy and was expected to recruit about 66 patients, who would be randomly assigned to receive the vaccine, or a placebo, over three months.
The trial was withdrawn due to a lack of on-time approval by the ethics committee of the partner institution responsible for recruiting the largest portion of patients planned to take part in the trial, however.
Common side effects of CV-MG01
In the Phase 1/2 trial, CV-MG01 was found to have a favorable safety profile, with most adverse events being mild to moderate in severity. The most frequent events were reactions at the site of injection, such as tenderness, pain, redness, or itching, which resolved spontaneously within days after the injection. No serious adverse events occurred after the injection and no safety issues were identified up to a year after the last injection.
Myasthenia Gravis News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
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