FDA Expands Argenx's Vyvgart Label to Treat Rare Disorder

Shares of Argenx ARGX rose nearly 4% on Friday after management announced that the FDA approved its subcutaneously administered Vyvgart Hytrulo (efgartigimod) for a second indication — chronic inflammatory demyelinating polyneuropathy (CIDP).

Vyvgart Hytrulo has been approved as a once-weekly 30-to-90-second subcutaneous injection to treat adult patients with CIDP, a rare autoimmune disease. Per argenx, the approval ofVyvgart Hytrulo makes it the first FDA-approved medication with a novel mechanism of action to treat CIDP in more than 30 years.

The drug was initially approved by the FDA last year to treat adults with generalized myasthenia gravis (gMG) indication. An intravenous formulation of the drug was approved by the FDA in 2021 to treat gMG and is marketed under the trade name Vyvgart. The approval of Vyvgart/Vyvgart Hytrulo marks the first and currently the only approval for a medication based on a neonatal Fc receptor (FcRn) blocker in the United States.

The latest FDA approval is based on data from the phase III ADHERE study, which evaluated the argenx drug in CIDP patients, regardless of prior treatment. The study met its primary endpoint — the drug helped cut the risk of relapse by 61% compared with placebo.

CIDP is a rare and serious autoimmune disease of the peripheral nervous system, marked by a range of disabling mobility and sensory issues, which include fatigue, muscle weakness and loss of feeling in arms and legs. Before the latest FDA approval, CIDP patients had limited options for treatment, which consisted of corticosteroids and plasma-derived therapies.

Unlike the existing treatments which could only manage symptoms of CIDP, treatment with Vyvgart Hytrulo also helps in improving mobility and sensory issues. Data from the ADHERE study also demonstrated that 69% of patients who received the drug showed evidence of clinical improvement, including improvements in mobility, function and strength.

argenx's shares rose as investors cheered the drug's approval, which is attributable to the drug's commercial potential. The company, which derives all its product revenues from the sale of Vyvgart and Vyvgart Hytrulo, is currently a market leader in gMG indication. Since its commercial launch in 2022, Argenx's product sales have been encouraging. Argenx recorded $398 million from product sales in first-quarter 2024, up 83% year over year and 6% quarter over quarter. With the latest label expansion, it could also establish itself as a market leader in CIDP indication.

Year to date, Argenx's shares have gained 3.7% against the industry's 5.8% fall.

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Argenx is also evaluating Vyvgart/Vyvgart Hytrulo in multiple proof-of-concept clinical studies, including membranous nephropathy and lupus nephritis (LN) indications.

Last month, management announced its decision to discontinue developing the drug in post-COVID-19-mediated postural orthostatic tachycardia syndrome (PC-POTS). This decision was based on data from a mid-stage study wherein treatment with the drug did not show clinical improvement in study participants with the disease.

Another company that secured the FDA's approval for CIDP indication is Takeda TAK. The agency expanded approval to Takeda's subcutaneous administered immune globulin treatment, Hyqvia, as a maintenance therapy for adults with CIDP in January. The Takeda drug is also approved for use in primary immunodeficiency in individuals aged two years and older.

Zacks Rank & Key Picks

Argenx currently carries a Zacks Rank #3 (Hold). A couple of better-ranked stocks in the overall healthcare sector include Arcutis Biotherapeutics ARQT and Heron Therapeutics HRTX, each carrying a Zacks Rank #2 (Buy) at present.

In the past 60 days, estimates for Arcutis Biotherapeutics' 2024 loss per share have narrowed from $2.49 to $1.60. During the same period, the loss estimates per share for 2025 have narrowed from $1.77 to $1.14. Year to date, shares of Arcutis have surged 162.9%.

Earnings of Arcutis Biotherapeutics beat estimates in three of the last four quarters while missing the mark on one occasion. Arcutis delivered a four-quarter average earnings surprise of 14.93%.

In the past 60 days, estimates for Heron Therapeutics' 2024 loss per sharehave narrowed from 22 cents to 10 cents. During the same period, estimates for 2025 have improved from a loss of 9 cents to earnings of 1 cent. Year to date, HRTX's shares have appreciated 90.0%.

Earnings of Heron Therapeutics beat estimates in three of the last four quarters while missing the mark on one occasion. HRTX delivered a four-quarter average earnings surprise of 30.33%.

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