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General Information
Vyvgart Hytrulo is a combination of efgartigimod alfa, a neonatal Fc receptor blocker, and hyaluronidase, an endoglycosidase.
Vyvgart Hytrulo is specifically indicated for the treatment of generalized myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor (AChR) antibody positive.
Dosing/Administation
Vyvgart Hytrulo is supplied as a solution for subcutaneous injection.
Because Vyvgart Hytrulo causes transient reduction in IgG levels, immunization with liveattenuated or live vaccines is not recommended during treatment with Vyvgart Hytrulo. Evaluate the need to administer age-appropriate immunizations according to immunization guidelines before initiation of a new treatment cycle with Vyvgart Hytrul.
The recommended dosage of Vyvgart Hytrulo is 1,008 mg / 11,200 units (1,008 mg efgartigimod alfa and 11,200 units hyaluronidase) administered subcutaneously over approximately 30 to 90 seconds in cycles of once weekly injections for 4 weeks.
Administer subsequent treatment cycles according to clinical evaluation. The safety of initiating subsequent cycles sooner than 50 days from the start of the previous treatment cycle has not been established.
If a scheduled dose is missed, Vyvgart Hytrulo may be administered up to 3 days after the scheduled time point. Thereafter, resume the original dosing schedule until the treatment cycle is completed.
Mechanism of Action
Vyvgart Hytrulo is a coformulation of efgartigimod alfa and hyaluronidase.
Efgartigimod alfa is a human IgG1 antibody fragment that binds to the neonatal Fc receptor (FcRn), resulting in the reduction of circulating IgG.
Hyaluronidase increases permeability of the subcutaneous tissue by depolymerizing hyaluronan. This effect is transient and permeability of the subcutaneous tissue is restored within 24 to 48 hours.
Side Effects
Adverse effects associated with the use of Vyvgart Hytrulo may include, but are not limited to, the following:
- respiratory tract infections
- headache
- urinary tract infection
Clinical Trial Results
FDA approval of Vyvgart Hytrulo was based on positive results from the Phase 3 ADAPT-SC study, which established the efficacy of Vyvgart Hytrulo by demonstrating a reduction in anti-AChR antibody levels comparable to intravenous Vyvgart in adult gMG patients. ADAPT-SC was a bridging study to the Phase 3 ADAPT study, which formed the basis for approval of intravenous Vyvgart in December 2021.
In the ADAPT-SC study, the primary endpoint of noninferiority was met and Vyvgart Hytrulo demonstrated mean total IgG reduction of 66.4% from baseline at day 29, compared to 62.2% with Vyvgart. Additional key secondary endpoints were met, which were consistent with efficacy measures from the ADAPT study identifying the correlation between total IgG reduction and clinical benefit in gMG.