Drug Update · Neurology

efgartigimod: 68% MG‑ADL Response in ADAPT; SubQ VYVGART HYTRULO Dosing

July 12, 2026

MG-ADL responder rate (AChR+)

68% (44/65) vs 30% (19/64) efgartigimod vs placebo [1]

MG-ADL responder rate (label)

67.7% vs 29.7% (p < 0.0001; OR 4.951; 95% CI 2.213-11.528) [12]

VYVGART IV approved dose

10 mg/kg IV once weekly for 4 weeks; 1,200 mg for patients ≥120 kg [2][9]

VYVGART HYTRULO subcutaneous dose (prefilled syringe)

1,000 mg efgartigimod alfa + 10,000 units hyaluronidase once weekly × 4 weeks (administer over 20–30 seconds) [4]

Clinical Perspective

Neurologists and neuromuscular specialists who treat adults with generalized myasthenia gravis should note that efgartigimod (VYVGART/VYVGART HYTRULO) is labeled for use in adult gMG patients and has demonstrated a higher proportion of MG-ADL responders in the AChR antibody–positive population in ADAPT ^[3]^[1]. The ADAPT primary-cycle results—68% versus 30% MG-ADL responders in AChR antibody–positive patients—support FcRn blockade as an effective mechanism to lower pathogenic IgG and improve activities of daily living in that subgroup ^[1]^[6]. How effective the subcutaneous coformulation VYVGART HYTRULO is specifically in anti‑AChR antibody–negative (seronegative) patients remains to be clarified from the reported excerpts of the provided sources?

Dr. Aditi Kulkarni · Neurology

VYVGART HYTRULO (efgartigimod alfa and hyaluronidase) is indicated for adult patients with generalized myasthenia gravis (gMG) per the product labeling ^[3]. The phase 3 ADAPT trial showed a Myasthenia Gravis Activities of Daily Living (MG-ADL) responder rate of 68% versus 30% with placebo in acetylcholine receptor (AChR) antibody–positive patients during the first treatment cycle ^[1]^[6].

Clinical Context

Efgartigimod is a human IgG1 antibody fragment engineered to block the neonatal Fc receptor (FcRn) and reduce circulating IgG levels, including pathogenic autoantibodies ^[2]^[6]. The intravenous formulation, VYVGART (efgartigimod alfa-fcab), received FDA approval for treatment of adult patients with generalized myasthenia gravis, initially for AChR antibody–positive disease per the FDA press announcement ^[5]^[2]. VYVGART HYTRULO is a coformulation of efgartigimod alfa with hyaluronidase for subcutaneous administration; the label states it is indicated for adult patients with gMG and for chronic inflammatory demyelinating polyneuropathy (CIDP) ^[3]^[6]. The ADAPT development program included both AChR antibody–positive and AChR antibody–negative populations and established clinical efficacy in the AChR antibody–positive cohort ^[1]^[6].

Key Findings

The ADAPT trial showed efgartigimod achieved an MG-ADL responder rate of 68% versus 30% with placebo in acetylcholine receptor antibody–positive patients during the first treatment cycle (MG-ADL responder defined as ≥2-point improvement sustained for ≥4 weeks) ^[1].
In the ADAPT (Study 1) dataset reported in the prescribing information, the MG-ADL responder rates during the first treatment cycle were 67.7% for efgartigimod intravenous versus 29.7% for placebo (p < 0.0001; odds ratio 4.951; 95% CI 2.213-11.528) ^[6].
The ADAPT trial also reported QMG responder rates favoring efgartigimod in anti‑AChR antibody–positive patients: 63.1% versus 14.1% during the first treatment cycle (p < 0.0001; odds ratio 10.842; 95% CI 4.179-31.200) ^[6].
The multicenter, randomized, placebo-controlled ADAPT program enrolled 167 patients in the pivotal study (84 randomized to efgartigimod and 83 to placebo), with 129 (77%) AChR antibody–positive across the cohort; efficacy analyses reported above were prespecified for the AChR antibody–positive population ^[1]^[6].

Safety & Tolerability

Respiratory tract infection (most common; reported in 33% of VYVGART-treated patients vs 29% placebo in Study 1) ^[2]^[4].
Headache (reported in 32% of VYVGART-treated patients vs 29% placebo in Study 1) ^[2]^[4].
Urinary tract infection (reported in 10% of VYVGART-treated patients vs 5% placebo in Study 1) ^[2]^[4].
Nasopharyngitis (reported in the ADAPT safety results: efgartigimod 10/84 [12%] vs placebo 15/83 [18%] for the IV formulation) ^[1].
Paraesthesia (reported in Study 1; 7% VYVGART vs 5% placebo) ^[4].
Myalgia (reported in Study 1; 6% VYVGART vs 1% placebo) ^[4].
Nausea (reported in the placebo-controlled study in anti-AChR antibody–negative patients; 7% VYVGART vs 5% placebo) ^[3].
Hypersensitivity reactions including anaphylaxis, hypotension leading to syncope, angioedema, dyspnea, rash, and urticaria have been reported; VYVGART and VYVGART HYTRULO are contraindicated in patients with serious hypersensitivity to efgartigimod alfa products or excipients ^[2]^[3]^[4].
Infusion-related or injection-related reactions have been reported, with symptoms such as hypertension, chills, shivering, and thoracic/abdominal/back pain occurring during or within an hour of administration ^[2]^[3].
Hematologic abnormalities observed more frequently with efgartigimod included below-normal white blood cell counts (12% vs 5%), lymphocyte counts (28% vs 19%), and neutrophil counts (13% vs 6%) in Study 1 ^[3].

Study Design

ADAPT (Study 1) was a multicentre, randomized, double-blind, placebo-controlled, phase 3 trial done at 56 neuromuscular academic and community centres in 15 countries; patients were randomized 1:1 to efgartigimod or matching placebo, with 167 patients enrolled (84 efgartigimod, 83 placebo) ^[1]. The primary endpoint for Study 1 was the proportion of acetylcholine receptor antibody–positive patients who were MG-ADL responders (≥2-point MG-ADL improvement sustained for ≥4 weeks) in the first treatment cycle; the primary analysis population was the modified intention-to-treat of AChR antibody–positive patients ^[1]^[6]. VYVGART HYTRULO’s label notes Study 3 demonstrated comparable pharmacodynamic effect to the IV formulation ^[6].

FAQ

Q1 What is VYVGART HYTRULO approved for?

VYVGART HYTRULO (efgartigimod alfa and hyaluronidase) is indicated for the treatment of adult patients with generalized myasthenia gravis (gMG) and for chronic inflammatory demyelinating polyneuropathy (CIDP) according to the product labeling. The intravenous formulation VYVGART is indicated for treatment of adult patients with generalized myasthenia gravis; ADAPT demonstrated benefit in AChR antibody–positive patients. Clinicians should consult current prescribing information for full dosing guidance.

Q2 How does efgartigimod (VYVGART/VYVGART HYTRULO) work?

Efgartigimod alfa is a human IgG1 antibody fragment that binds the neonatal Fc receptor (FcRn), blocking IgG recycling and reducing circulating IgG levels, including pathogenic autoantibodies implicated in gMG. Hyaluronidase in the HYTRULO coformulation increases subcutaneous tissue permeability to allow subcutaneous administration of efgartigimod. Clinicians should consult current prescribing information for full dosing guidance.

Q3 What is the recommended dose of VYVGART HYTRULO?

For generalized myasthenia gravis, the VYVGART HYTRULO prefilled syringe contains 1,000 mg efgartigimod alfa and 10,000 units hyaluronidase administered subcutaneously over approximately 20 to 30 seconds in cycles of once-weekly injections for 4 weeks. The vial formulation provides 1,008 mg with 11,200 units hyaluronidase administered over approximately 30 to 90 seconds in the same 4-week cycle. Administer subsequent treatment cycles based on clinical evaluation. Clinicians should consult current prescribing information for full dosing guidance.

Q4 What are the most common side effects of efgartigimod/VYVGART HYTRULO?

Across the pivotal studies and labeling, the most common adverse reactions reported in patients treated with efgartigimod (reported in at least 10% in Study 1) include respiratory tract infections, headache, and urinary tract infection. Injection-site reactions are common with the subcutaneous HYTRULO formulation (reported ≥15% in gMG and CIDP cohorts). Hypersensitivity reactions and infusion/injection-related reactions have been observed; infections and hematologic abnormalities have also been reported. Clinicians should consult current prescribing information for full dosing guidance.

efgartigimod: 68% MG‑ADL Response in ADAPT; SubQ VYVGART HYTRULO Dosing

efgartigimod: 68% MG‑ADL Response in ADAPT; SubQ VYVGART HYTRULO Dosing

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

Study Design

FAQ

References

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