Efgartigimod: A Review in Generalised Myasthenia Gravis

Efgartigimod (Vyvgart (R); Vyvgart (R) Hytrulo) is a neonatal fragment crystallizable receptor (FcRn) antagonist indicated for the treatment of generalised myasthenia gravis (gMG) in adults who are acetylcholine receptor (AChR) antibody positive (Ab+). Efgartigimod is approved for both intravenous (IV) and subcutaneous (SC) use. In a pivotal phase III trial, IV efgartigimod was associated with significant and clinically meaningful improvements in myasthenia gravis symptoms and reductions in disease burden. The beneficial effects of IV efgartigimod were reproducible, durable and maintained over the long term. IV efgartigimod also improved health-related quality of life (HRQOL). In another phase III trial, SC efgartigimod PH20 was noninferior to IV efgartigimod in reducing total immunoglobulin G levels. Clinical improvement with SC efgartigimod PH20 was consistent with that of IV efgartigimod and was reproducible over the long term. Efgartigimod was generally well tolerated; the most common adverse events were headache and infections (with IV efgartigimod) and injection-site reactions (with SC efgartigimod PH20). Although further long-term data are required, IV and SC formulations of efgartigimod provide effective, generally well-tolerated and flexible treatment options for adults with AChR Ab+ gMG. Generalised myasthenia gravis (gMG) is a chronic, autoimmune disorder caused by impaired communication between the nerves and muscles. Recently, new targeted therapies have been developed for gMG, including FcRn antagonists such as efgartigimod (Vyvgart (R); Vyvgart (R) Hytrulo). Efgartigimod works by reducing circulating levels of disease-causing antibodies. The drug is available as an IV infusion or an SC injection. In patients with gMG, IV efgartigimod significantly reduced disease burden and improved myasthenia gravis symptoms. These beneficial effects were long-lasting and repeatable across multiple treatment cycles. IV efgartigimod provided consistent clinically meaningful improvement over the long term (up to 17 treatment cycles) and was generally well tolerated. The efficacy and tolerability of SC efgartigimod PH20 was consistent with that of IV efgartigimod. The most common adverse events were headache and infections (with IV formulation) and injection-site reactions (with SC formulation). Thus, efgartigimod is an effective and generally well-tolerated treatment option for adults with gMG, with the flexibility of IV or SC administration.