FDA clears Argenx’ Vyvgart Hytrulo for rare disease CIDP

Netherlands biotech Argenx has a second FDA approval for its FcRn inhibitor Vyvgart Hytrulo, adding a new indication in chronic inflammatory demyelinating polyneuropathy (CIDP) for a drug that it hopes could find a use in more than a dozen diseases.

Vyvgart Hytrulo (efgartigimod alfa/hyaluronidase) is the first drug in the FcRn blocker class to treat CIDP, a rare autoimmune disease of the peripheral nervous system that causes fatigue, muscle weakness, and loss of feeling that can lead to serious disability and the need to use a wheelchair.

In a statement, Argenx said that the subcutaneously administered drug is the first “meaningful” new treatment option for the approximately 24,000 people living with CIDP in the US in more than three decades.

Drug treatment for CIDP currently relies on corticosteroids, high-dose intravenous immune globulins – including Takeda’s HyQvia, which was approved for CIDP by the FDA in January – or a procedure called plasmapheresis. The latter involves removing patients’ blood and returning the whole cells without the plasma containing the auto-antibodies that cause the disease.

The approval is based on the results of the ADHERE trial, which met its primary endpoint by showing a 61% lower risk of relapse with Vyvgart Hytrulo compared to placebo. All told, 69% of patients were deemed to have shown a response to Argenx’s drug.

Vyvgart Hytrulo – or rather its intravenously dosed sister product Vyvgart (efgartigimod alfa) – was the first FcRn blocker to be approved by the FDA, getting the go-ahead in December 2021 for generalised myasthenia gravis (gMG).

Vyvgart Hytrulo was cleared for gMG in the US a year ago, and Argenx chose to use a priority review voucher (PRV) to shorten the CIDP timeline, which signals the importance it attaches to the new indication.

Other attempts to extend the indications of Vyvgart Hytrulo to include diseases like pemphigus vulgaris/pemphigus foliaceus and primary immune thrombocytopenia (ITP) have suffered clinical trial setbacks, although it was recently approved in Japan for ITP. The drug remains in development across around 15 indications overall and – like FcRN rival nipocalimab, from Johnson & Johnson – has been tipped by analysts to make multibillion-dollar sales at peak.

The Vyvgart franchise overall brought in $1.2 billion in sales last year, but future growth forecasts have focused on the subcutaneous version, which allows for a once-weekly injection administered by a healthcare professional that takes between 30 and 90 seconds, rather than a weekly, hour-long IV infusion delivered at a clinic with Vyvgart.