FDA Approves Uplizna, First CD19-Targeted Therapy for Generalized Myasthenia Gravis

December 16, 2025

SILVER SPRING, Md. — The U.S. Food and Drug Administration (FDA) has approved Uplizna (inebilizumab-cdon) for the treatment of generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive. The decision, announced late last week, marks the arrival of the first CD19-targeted B-cell therapy for the rare autoimmune disease, offering a new mechanism of action and a significantly less burdensome dosing schedule for patients.

Developed by Amgen, Uplizna is designed to target and deplete CD19-positive B cells, including the plasmablasts and plasma cells responsible for producing the harmful autoantibodies that drive gMG. Unlike existing treatments that remove circulating antibodies or inhibit complement activation, this “first-in-class” approach aims to address the disease’s biological root cause upstream.

“This approval marks a significant advancement for people living with gMG,” said Dr. Jay Bradner, Executive Vice President of Research and Development at Amgen. “By selectively targeting CD19-positive B cells, Uplizna offers a new approach to treatment… conveniently dosed twice a year and delivers durable efficacy.”

Clinical Trial Results: The MINT Study

The FDA’s approval rests on positive data from the Phase 3 MINT (Myasthenia Gravis Inebilizumab Trial), the largest biologic study to date involving both AChR-positive and MuSK-positive patients. The randomized, double-blind, placebo-controlled trial enrolled 238 adults and evaluated the drug’s safety and efficacy over 26 weeks.

Key findings included:

• Functional Improvement: Patients treated with Uplizna showed a statistically significant improvement in their Myasthenia Gravis Activities of Daily Living (MG-ADL) scores. At Week 26, the treatment group improved by an average of 4.2 points compared to 2.2 points for the placebo group ($p < 0.0001$).

• Steroid Reduction: Uniquely, the MINT trial protocol required a structured taper of corticosteroids. By the end of the 26-week period, 87.4% of patients receiving Uplizna had successfully tapered their prednisone dosage to 5 mg per day or less, reducing the long-term burden of steroid side effects.

• Sustained Efficacy: Improvements were observed early and maintained throughout the study period, with efficacy seen across both AChR-positive and the harder-to-treat MuSK-positive subpopulations.

“Uplizna showed strong efficacy at 26 weeks in both AChR+ and MuSK+ patients,” noted Dr. Richard J. Nowak, the trial’s global principal investigator and Director of the Myasthenia Gravis Clinic at Yale University. “MINT also uniquely required steroid tapering, recognizing that long-term steroid use adds to the overall burden of disease.”

A Shift in Treatment Burden

Generalized myasthenia gravis is a chronic autoimmune disorder characterized by fluctuating muscle weakness that can affect breathing, swallowing, speech, and limb function. For decades, treatment relied heavily on broad immunosuppressants and corticosteroids, which carry significant side effects.

While recent years have seen the approval of targeted therapies like FcRn blockers (e.g., Vyvgart, Rystiggo) and complement inhibitors (e.g., Soliris, Ultomiris), many of these require frequent infusions or subcutaneous injections—sometimes as often as every week or two.

Uplizna distinguishes itself with its dosing frequency. After two initial loading doses administered two weeks apart, patients require only one intravenous infusion every six months.

“Managing a rare and chronic illness can mean facing unpredictable relapsing symptoms and demanding treatment schedules,” said Samantha Masterson, CEO of the Myasthenia Gravis Foundation of America (MGFA). “This approval marks an important milestone, offering durable efficacy and a dosing schedule that provides people living with generalized myasthenia gravis six months of treatment-free time between maintenance doses.”

Safety and Limitations

While the approval is a major step forward, Uplizna is not without risks. As an immunosuppressive therapy that depletes B cells, it can increase the risk of infections. In the MINT trial, the most common adverse reactions included urinary tract infections, nasopharyngitis (common cold), and headache.

Infusion reactions were also reported in approximately 10% of patients. The FDA label includes warnings regarding the potential for increased risk of infection and advises that patients should not receive live vaccines during treatment.

Furthermore, while the drug is approved for the vast majority of gMG patients (those with AChR or MuSK antibodies), it is not currently indicated for the small percentage of patients who are “seronegative” (lacking detectable antibodies).

Implications for Public Health

The approval of Uplizna introduces a third major class of targeted biologics for gMG, fostering a more competitive treatment landscape that allows neurologists to tailor therapy to individual patient needs. For patients who have struggled with adherence to frequent infusion schedules or who have not responded adequately to FcRn blockers or complement inhibitors, this B-cell depleting therapy offers a vital new option.

“The approval of Uplizna represents meaningful progress for people living with generalized myasthenia gravis,” said Angela Lek, PhD, Chief Research Officer at the Muscular Dystrophy Association. “It reflects the continued evolution of targeted, mechanism-based treatments.”

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to y²our treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.

References

1. Amgen. (2025, December 11). FDA Approves UPLIZNA® (inebilizumab-cdon) for the Treatment of Generalized Myasthenia Gravis (gMG). [Press Release].

2. U.S. Food and Drug Administration (FDA). (2025). Highlights of Prescribing Information: UPLIZNA (inebilizumab-cdon) injection, for intravenous use.