Argenx: Lowering Our Valuation on Disappointing ITP Data, Shares Remain Slightly Undervalued

We’re slightly lowering our fair value estimate for Argenx to $539/EUR 490 from $574/EUR 543 following a disappointing phase 3 trial failure for subcutaneous product Vyvgart Hytrulo in primary immune thrombocytopenia, or ITP. While the drug appeared to be effective in lowering levels of IgG antibodies, the trial did have a slightly higher percentage of patients who had failed numerous prior therapies than in the successful phase 3 study of infused Vyvgart, and patients in the placebo arm had surprising responses. Based on this uncertainty, we have reduced our assumed probability of Vyvgart’s global approval in ITP to 30% (from 70%). This lowers our assumed ITP sales of Vyvgart to roughly $300 million in 2032 from $700 million previously.