IMAAVY – Dosing Window During Generalized Myasthenia Gravis Clinical Trials in Adult Patients

SUMMARY

• The company cannot recommend any practices, procedures, or usage of IMAAVY that deviate from the approved labeling.
• In a 24-week, phase 3, randomized, double-blind, placebo (PBO)-controlled trial in adult patients with generalized myasthenia gravis (gMG), the dosing window was ±2 days from the scheduled infusion date during the double-blind phase and ±3 days during the open-label extension (OLE) phase.¹

PRESCRIBING INFORMATION

Dosage and Administration  

Recommended dosage in adult and pediatric patients 12 years of age and older 

• The recommended initial dosage of IMAAVY is 30 mg/kg administered once via intravenous (IV) infusion over at least 30 minutes.²  
• Two weeks after the initial dosage, administer a maintenance dosage of 15 mg/kg via
• IV infusion over at least 15 minutes. Continue the maintenance dosage every two weeks thereafter.² 
• If a scheduled infusion is missed, administer the dose of IMAAVY as soon as possible. Resume dosing, maintaining the treatment interval.²

clinical DATA

VIVACITY-MG3 Study

Antozzi et al (2025)³ evaluated the efficacy and safety of IMAAVY in adults with gMG in a phase 3, randomized, multicenter, double-blind, PBO-controlled study with an ongoing OLE phase.

Study Design/Methods

• Patients (≥18 years of age) with anti-acetylcholine receptor (AChR), anti-muscle-specific tyrosine kinase (MuSK) or low-density lipoprotein receptor 4 (LRP4) antibody positive or seronegative (in all countries except France) gMG (Myasthenia Gravis Foundation of America [MGFA] class IIa-IVb) were included in the study.^3,4 
• The study consisted of a ≤4-week screening phase, followed by a 24-week, double-blind, PBO-controlled treatment phase, a variable-duration, OLE phase, and a safety follow-up at 8 weeks after the last infusion (included patients who withdrew or discontinued after receiving any amount of the study intervention).^1,3,4 
• Eligible patients were randomized (1:1) to receive a loading dose of IV IMAAVY
• 30 mg/kg at week 0, followed by 15 mg/kg every 2 weeks (Q2W) or matching PBO through week 24 in addition to standard of care (SOC) therapy.
• Patients entering the OLE phase continued to receive IMAAVY 15 mg/kg IV Q2W in addition to SOC.⁵ 

Dosing Window

• During the double-blind, PBO-controlled phase, the dosing window was ±2 days from the scheduled infusion date.¹
• During the OLE phase, the dosing window was ±3 days from the scheduled infusion date.¹ 

Literature Search

A literature search of MEDLINE^®, EMBASE^®, BIOSIS Previews^®, DERWENT^® (and/or other resources, including internal/external databases) was conducted on 14 September 2026.