FDA starts review of Argenx drug in rare disease CIDP

The US FDA has said it plans to deliver a decision in June on the use of Argenx’ Vyvgart Hytrulo in chronic inflammatory demyelinating polyneuropathy (CIDP), as the company tries to turn around a run of bad news with the drug.

If approved, Vyvgart Hytrulo (efgartigimod alfa) will be 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.

At the moment, drug treatment for CIDP relies on corticosteroids or high-dose intravenous immune globulins, such as Takeda’s Hyqvia and Gammagard Liquid, or a procedure called plasmapheresis, which involves removing patients’ blood and returning the whole cells without the plasma that contains auto-antibodies that cause the disease.

The filing 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.

The FDA has started a priority six-month review of the supplemental Biologics License Application (sBLA) for Vyvgart Hytrulo in CIDP, saying it plans to deliver a decision by 21st June. Argenx chose to use a priority review voucher (PRV) to speed up the process, which signals the importance it attaches to the new indication.

Vyvgart Hytrulo – a subcutaneous formulation of the company’s intravenous Vyvgart product – has been approved by the FDA to treat generalised myasthenia gravis (gMG), but Argenx has suffered setbacks in its efforts to extend uses into new areas, including pemphigus vulgaris/pemphigus foliaceus and primary immune thrombocytopenia (ITP).

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

The franchise competes in gMG with well-established IV therapies, including AstraZeneca’s complement C5 inhibitors Soliris (eculizumab) and Ultomiris (ravulizumab) and two recently-approved subcutaneous therapies from UCB, C5 inhibitor Zilbrysq (zilucoplan), and FcRn-targeting antibody Rystiggo (rozanolixizumab). Approval in CIDP would allow Netherlands-based Argenx to carve out a niche for its product.

“CIDP is yet another example of an autoimmune disease that has not been well understood, and for which there has been insufficient innovation for patients,” said Luc Truyen, Argenx’s chief medical officer.

“FDA’s acceptance of the sBLA represents an important milestone in our continued drive to bring novel treatments for rare, autoimmune diseases, and a significant step forward for people whose lives have been profoundly impacted by this devastating disease,” he added.

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