SUMMARY

• Please refer to local labeling for relevant information on IMAAVY and occurrence of infusion-related reactions.
• In a 24-week, phase 3, randomized, double-blind, placebo (PBO)-controlled trial in adult patients with generalized myasthenia gravis (gMG), infusion-related reactions were reported in 10% and 11% of patients in the IMAAVY + standard of care (SOC) and PBO + SOC groups, respectively.¹ 
• In the ongoing open-label extension (OLE) phase, the events per patient-years (PY) rate for infusion-related reactions in the combined IMAAVY group (n=176) was 0.07, with 17 events reported in 10 patients during a median follow-up of 72 weeks.² 

CLINICAL DATA

VIVACITY-MG3

Antozzi et al (2025)¹ evaluated the efficacy and safety of IMAAVY in adults with gMG in a phase 3, randomized, multicenter, double-blind, PBO-controlled study.

Study Design/Methods

• Patients (≥18 years of age) with anti- acetylcholine receptor (AChR), 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.^1,3
  • The safety analysis population included all randomized patients who received ≥1 dose (partial or complete) of any study treatment in the double-blind phase or of IMAAVY in the OLE phase.^1,2 
• 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 safety follow-up at 8 weeks after the last infusion.^1,4 
  • Patients who withdrew or discontinued after receiving any amount of the study intervention were required to complete a safety follow-up assessment at 8 weeks after the last dose.⁴ 
• Eligible patients were randomized (1:1) to receive a loading dose of intravenous (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 SOC therapy.¹ 
• Patients entering the OLE phase continued to receive IMAAVY 15 mg/kg Q2W in addition to SOC.² 

Results

Double-Blind Phase

• A total of 196 patients (IMAAVY, n=98; PBO, n=98) were included in the safety analysis dataset.¹ 
• Infusion-related reactions were reported in 10% (10/98) of patients in the IMAAVY + SOC group and 11% (11/98) of patients in the PBO + SOC group, with no reported cases of severe or serious infusion reactions in either group.¹ 

Ongoing-OLE Phase

• A total of 176 patients were included in the safety analysis set with a median follow-up of 72 weeks (IMAAVY→IMAAVY, n=88; PBO→IMAAVY, n=88). For details on infusion-related reactions, see Table: Infusion-related Reactions in the OLE Phase.

Literature Search

A literature search of MEDLINE^®, EMBASE^®, BIOSIS Previews^®, and DERWENT^® (and/or other resources, including internal/external databases) was conducted on 09 June 2025.