Nipocalimab: a significant milestone in the treatment of myasthenia gravis approved by the FDA

Abstract

Nipocalimab is a newly approved therapeutic agent that modulates a distinct immune transport pathway and has shown considerable promise in treating patients with motor impairment stemming from dysregulated antibody responses. Cleared for use in individuals aged 12 and older, this biology marks a notable advancement in managing many autoimmune conditions, including myasthenia gravis which exists in 150–200 individuals per million. The results of nipocalimab in patients with the latter condition were read in peer-reviewed literature and clinical trial data and key outcomes were extracted. The disease in focus is characterized by fluctuating muscular weakness and reduced endurance due to immune system disruption at the neuromuscular interface. While existing interventions offer some relief, many are limited by side effects or suboptimal long-term control, underscoring the need for better-targeted therapies. Interrupting the mechanism that prolongs the circulation of specific immune proteins presents a refined strategy to lower pathogenic activity while maintaining overall immunological integrity. This compound disrupts the cellular routing system involved in antibody preservation, leading to a selective decline in disease-associated immunoglobulins while leaving protective antibodies largely unaffected. Clinical studies across healthy and affected populations have demonstrated a favorable safety record and meaningful biological responses, including enhanced physical functioning. Late-stage trials have confirmed significant improvements in key health parameters, reinforcing the agent’s therapeutic value. This biology introduces a more precise, well-tolerated, and durable option for treating myasthenia gravis.

On 29 April 2025, the US Food and Drug Administration (FDA) approved a monoclonal antibody Imaavy, Nipocalimab-aahu by Johnson & Johnson as an effective treatment for patients with antibody-positive generalized myasthenia gravis (gMG) in patients aged 12 and older, representing a major milestone in the treatment of antibody-driven neuromuscular diseases^[1]. It offers a new treatment option with the potential to deliver long-term disease suppression for individuals living with gMG ^[2].

This article is compliant with the TITAN Guidelines 2025 – governing declaration and use of AI^[3].

A comprehensive literature search was conducted using PubMed and Google Scholar to identify clinical trials involving nipocalimab up to April 2025. Relevant studies were reviewed, and key findings have been summarized and highlighted in this article.

MG is an immune-mediated disease that typically presents with muscle weakness; it is caused by autoantibodies directed against the postsynaptic acetylcholine receptors, which bind to the acetylcholine receptors, thus preventing ACh from stimulating muscle contraction effectively. This leads to focal or generalized muscle weakness, with clinical presentations ranging from isolated ocular symptoms like ptosis and double vision to dysphagia, slurred speech, and limb weakness. In severe cases, weakness can affect the muscles of respiration. Muscle weakness fluctuates in severity, increasing as the day progresses and often improving with rest^[4]. Currently, treatment options for gMG that affect multiple muscle groups beyond the eyes (bulbar, limb, and axial muscles) include cholinesterase inhibitors, which enhance neuromuscular transmission, as well as corticosteroids and immunosuppressants. However, as the limitations and side effects of corticosteroids became evident, a variety of alternative therapies were introduced in recent decades, all characterized by immunosuppressive properties. In addition, there are treatment options such as plasma exchange, intravenous immunoglobulins, or immunoadsorption methods that can selectively remove specific molecules like pathogenic antibodies from blood plasma without the need for blood product replacement^[5].Despite their use, many patients experience persistent gMG symptoms, exacerbations, and adverse effects that limit their use, thus leading to a diminished quality of life and a sustained burden of disease. These constraints highlight the need for safe and more effective treatments overall^[6]. Over the past few years, many biological agents have been developed for MG. A recent treatment for autoimmune conditions like MG is blocking the neonatal Fc receptor, which can be achieved using these biologicals. By binding to the Fc portion of IgG, the neonatal receptor protects the IgG from lysosomal breakdown. Blocking the receptor with this mechanism presents a viable strategy without compromising the immune system^[7]. Nipocalimab is a fully human monoclonal antibody that blocks the FcRn receptor by binding to it. The neonatal Fc receptor is responsible for the long half-life of IgG in the blood; thus, nipocalimab decreases the autoantibody levels in the blood. This drug does not decrease the synthesis of IgG or other classes of antibodies hence protecting the immune system of the body. This causes a decrease in circulating pathogenic antibodies without decreasing immunity, making it distinct from standard immunosuppressive therapies. Various clinical trials have been conducted, with extremely compelling evidence suggesting the benefits of nipocalimab with lower side effects compared to other treatment options currently used in individuals with MG.

Recent discovery of several antibodies including five new molecules has gained approval including efgartigimod, and rozanolixizumab, with others in various stages of clinical trials,^[8]. Nipocalimab has many advantages over the other antibodies; it has been proven safe in pregnancy as it does not have significant transplacental transfer^[9]. It also provided more consistent, sustained disease control in gMG compared to efgartigimod and rozanolixizumab, showing improvements in myasthenia gravis activities of daily living (MG-ADL) scores versus both the latter antibodies. Despite trial differences, nipocalimab’s cumulative efficacy and early onset make it a strong therapeutic option among FcRn blockers. As no direct comparative trial has taken place, unanchored MAICs showed a significant benefit of nipocalimab starting from week 8, sustained through week 24. Bucher ITC estimates also numerically favored nipocalimab at multiple later time points^[10]. The drug has also been shown to treat other autoimmune diseases and received a breakthrough therapy designation by the FDA in November of 2024 for Sjogren’s disease.

Concerning MG, three clinical trials have taken place. The phase 1 trial was carried out in Japan on 24 healthy volunteers to evaluate the pharmacokinetics and pharmacodynamics of nipocalimab. The study showed that single intravenous doses of nipocalimab (10–60 mg/kg) were well-tolerated in the Japanese volunteers and exhibited characteristics similar to those seen in non-Asian populations. Robust evidence thus signifies the therapeutic benefit of nipocalimab used in the treatment of IgG-mediated diseases across diverse patient groups^[11]. Moreover, a phase 2 clinical trial VIVACITY-MG was conducted in patients with gMG. The study demonstrated that Nipocalimab was profoundly safe, exhibited good tolerability, and provided statistically significant evidence of clinical efficacy (P = 0.031) with a dose-dependent reduction in both MG-ADL, a score to assess the severity of the disease with 83.8% of patients completing treatment through day 57 and serum total IgG levels. The study was conducted across multiple facilities in 8 nations. Adult participants (18 years or older) were enrolled at 38 sites located in the United States, Canada, Germany, Italy, Poland, Spain, Belgium, and the United Kingdom. The study analyzed the safety and therapeutic potential of intravenous nipocalimab. The 68 gMG patients participated with 54 receiving nipocalimab and 14 receiving a placebo who had inadequate responses to standard treatments over 8 weeks. Treatment-emergent adverse events were similar to placebo, 83.3% versus 78.6%, signifying the benefits of nipocalimab over other current medications^[12].

Nevertheless, the phase 2 trial revealed limited clinical benefits. The recently completed phase 3 VIVACITY study delivered favorable results, positioning nipocalimab amidst available FcRn inhibitors. It exhibited the longest period of sustained disease control, with efficacy noted in patients with AChR, MuSK, and LRP4 positive gMG. A Phase 3 trial, The Vivacity-MG3, measured the therapeutic index and treatment response of nipocalimab in adult patients with gMG. Conducted from July 2021 to November 2023, a 24-week trial enrolled 199 participants, including 153 individuals who tested positive for autoantibodies and had shown inadequate response to standard treatment regimens. The 153 patients who participated were randomly assigned to either the group receiving nipocalimab (77) or a placebo (76), alongside their existing therapies, which were their standard of care. Those treated with Nipocalimab showed improvement in the MG-ADL score (P = 0.0024), which was statistically significant. The therapy led to a significant decrease in total IgG, including pathogenic autoantibodies, by up to 75% over 24 weeks. Importantly, levels of IgA, IgM, and IgE remained unchanged, indicating a targeted immunomodulatory effect. The adverse events were commensurate between the treatment and placebo groups, reported in 84% of participants. Concerning adverse events occurring in 9% of the nipocalimab group and 14% of the placebo group, the most frequently reported side effect was a strong headache (14% in the nipocalimab group vs. 17% in the placebo group). Other side effects included muscle spasms, COVID-19 and infusion reactions. The findings from the Vivacity-MG3 trial signify nipocalimab as an effective, targeted treatment for antibody-positive gMG, offering both clinical efficacy and a favorable safety profile. Its reduction of total lgG including pathological lgG, without broadly suppressing the immune system, supports its use as a novel immunotherapy. However, considering this emerging therapy, further studies are currently being analyzed by specialists to evaluate its long-term safety and therapeutic durability^[13].

In conclusion, nipocalimab offers a less frequent dosing schedule than other FcRn inhibitors, with maintenance infusions every 2 weeks intravenously, compared with weekly subcutaneous administrations for rozanolixizumab and weekly intravenous or subcutaneous dosing for efgartigimod^[14]. While indirect analyses suggest potentially more durable disease control relative to approved FcRn blockers, the absence of active, head-to-head comparative trials – particularly reliance on unanchored MAIC methods – introduces potential bias. As with all FcRn inhibitors, total IgG reduction may increase infection risk and necessitate careful vaccine scheduling, leaving the long-term implications of repeated cyclic use uncertain. Nipocalimab’s list price is approximately US $12 480 per 1200 mg/6.5 mL vial^[15], compared with US $3275 per 140 mg vial for rozanolixizumab and US $6600 per 20 mL vial for efgartigimod. However, true treatment costs are determined by dosing frequency, treatment duration, and patient weight, limiting the accuracy of direct cost comparisons across the class.

Ethical approval

Not applicable.

Consent

Not applicable.

Sources of funding

None.

Author contributions

I.S: theorization, methodology, writing the original draft and editing; M.S: writing, reviewing, editing and submission of the article; M.A.H.: reviewing, editing and submission of the article.

Conflicts of interest disclosure

The authors declare no conflicts of interest.

Research registration unique identifying number (UIN)

None.

Guarantor

Mawiya Sana.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Data availability statement

None.