Japan has recently approved argenx’s  Vyvdura (efgartigimod alfa and hyaluronidase-qvfc) subcutaneous (SC) injection for the treatment of adult patients with generalized myasthenia gravis (gMG), who do not have sufficient response to steroids or non-steroidal immunosuppressive therapies (ISTs). While introducing a novel subcutaneous administration route, Vyvdura adds to Japan’s myasthenia gravis (MG) treatment options. However, differentiation from the existing therapies remains marginal, leaving an unmet need for a unique and specifically curative approach in MG treatment, says GlobalData, a leading data and analytics company.

With the latest approval, Japan has expanded its treatment armamentarium against MG with two argenx formulations: the intravenous (IV) Vyvgart (efgartigimod alfa), first sanctioned by the Ministry of Health, Labour and Welfare (MHLW) in January 2022, and the subcutaneous (SC) Vyvdura. This adds to the existing lineup of four IV disease-modifying therapies (DMTs) – AstraZeneca’s Soliris (eculizumab), Ultomiris (ravulizumab LA), argenx’s Vyvgart, UCB’s Rystiggo (rozanolixizumab), and one SC therapy, UCB’s Zilbrysq (zilucoplan), in Japan

Sasmitha Sahu, Pharma Analyst at GlobalData, comments: “The expanded approval of Vyvgart offers a new method of administration for adult MG patients  refractory to the first line of treatment options. However, in contrast to Japan, where patients can self-administer the treatment at home, the equivalent product Vyvgart Hytrulo requires administration by a healthcare professional in the US. As per argenx, this is simply an alternative delivery method, aimed at maintaining Vyvgart’s market presence, especially in light of UCB’s recent approval of a self-administered SC therapy.”

Although UCB is positioning Zilbrysq as the first self-administered drug, patients recieving Zilbrysq are required to be vaccinated with meningococcal vaccination, adding another complication to this SC competitor.

GlobalData’s recent report, Myasthenia Gravis: Opportunity Assessment and Forecast, reveals that the market for MG across the seven major markets is expected to witness at a compound annual growth rate (CAGR) of 8.3% from $3 billion in 2022 to $6.7 billion in 2032 , with an expected contribution of 6.4% from Japan. It was the second country to approve all targeted DMTs after the US and ahead of EU for MG.

Sahu adds: “The recent influx of several novel targeted DMTs have shown to improve treatment rates and drive growth within the off-label therapy refractory MG market but are associated with higher costs and constrained insurance. The Japanese guidelines for MG treatment that were last updated in 2022 still suggest off-label symptomatic therapies like acetyl cholinesterase inhibitors, glucocorticoids, and immunosuppressants as the first line treatment options for MG.”

Of the six pipeline drugs in Phase III, only Horizon Therapeutics’ inebilizumab and Chugai’s satralizumab are against the targets other than FCRN and complement C5.

Sahu concludes: “Even majority of the late stage pipeline molecules have mechanisms similar to the approved DMTs and are unlikely to differentiate themselves from the approved therapies. If approved, they have the potential to bring the overall prices down by increasing competition in the market. However, none of them are being developed as a first line of therapy or as a curative therapy.”

(7MM: the US, France, Germany, Italy, Spain, the UK, and Japan)