Takeaways from the Myositis R&D Spotlight session

Research evidence excerpt

Takeaways from the Myositis R&D Spotlight session

J P M O R G A N Europe Equity Research

24 June 2026

Argenx

Yesterday we attended the R&D spotlight session for Autoimmune Myositis in European Pharmaceuticals &

Boston. Here, Argenx disclosed further information regarding the subgroup Biotechnology

patient population in the Phase II trial, where IMNM patients constituted c.60% of Richard Vosser AC

patients and demonstrated a statistically significant result in this subgroup (44-20) 7742-6652

alone, and DM patients (c.30% of patients) also showed a clear signal of richard.vosser@jpmorgan.com

efficacy, albeit with this subgroup not sufficiently powered to show a stat sig J.P. Morgan Securities plc

benefit in Phase II. Given that Phase II enrollment recruited in similar proportions Sophia Graeff Buhl Nielsen AC

to Phase III, Argenx will now analyse the primary end point for Phase III in IMNM (44-20) 7742-3918

sophia.graeffbuhlnielsen@jpmorgan.com

and DM separately and file on this basis, and given a limited number of patients J.P. Morgan Securities plc

in PM they now no longer see a registrational path for PM. With yesterday’s session Zain Ebrahim

providing more insight around the potential efficacy and powering of the IMNM (44-20) 3493-1163

portion of the ALKIVIA trial, we this as further de-risking the opportunity for zain.ebrahim@jpmorgan.com

Vyvgart in IMNM, which we expect could be c.$5bn in itself assuming a 50% J.P. Morgan Securities plc

penetration of the 20k patient population. Furthermore, we continue to see a path Khushi Bihani

forward for Vyvgart in DM, where despite greater heterogeneity in the patients and (91-22) 6157-4103

a small number of patients enrolled increasing the risk around whether this part of khushi.bihani@jpmorgan.com

J.P.