Brussels, Tuesday - Shares of Argenx fell 5.7% in Brussels trading following an update to the company's late-stage clinical program for Vyvgart in myositis treatment.
The Belgian biotech firm said it will no longer pursue one myositis subtype within the program and will instead evaluate the two remaining subgroups separately in the ongoing late-stage trial. Company statements said that one subgroup showed less robust evidence of efficacy, prompting the change in approach.
The announcement, presented along with research data on Tuesday, led investors to reassess the development path for Vyvgart and produced the immediate share-price reaction. Management characterized the revision as an adjustment to the program's development strategy based on the subgroup data.
Investment banking commentary accompanied the trial update. J.P. Morgan said that while there may be concerns about the likelihood of success in the dermatomyositis, or DM, subtype, the updated strategy provides greater confidence that the immune-mediated necrotizing myopathy, or IMNM, subgroup could achieve its endpoints. J.P. Morgan estimated that successful outcomes in the IMNM subgroup could add approximately 150 per share to Argenx's stock.
Vyvgart is being developed as a treatment for myositis, which comprises a group of rare autoimmune diseases that cause muscle inflammation and weakness. The company did not add new numerical targets for timelines in the update; it focused on the decision to narrow and separately analyze subgroups in the late-stage trial.
What happened
- Argenx shares fell 5.7% in Brussels trading on Tuesday following a clinical-program update.
- The company said it will no longer pursue one myositis subtype and will analyze the two remaining subgroups independently in the late-stage Vyvgart trial.
- One subgroup was described by the company as showing less robust evidence of efficacy, prompting the strategic shift.
Analyst reaction
J.P. Morgan highlighted concerns about the DM subtype's likelihood of success but said the revised strategy increases confidence in the IMNM subgroup meeting its endpoints. The bank estimated a potential upside of about 150 per share if IMNM meets its goals.
Note on information limits - The update focused on subgroup performance and the program's altered design. The company did not provide additional efficacy figures for the subgroups beyond describing one as showing less robust evidence, and it did not announce changes to regulatory timelines in the material presented on Tuesday.