UCB needs a stronger rare disease hand

Data from two generalised myasthenia gravis projects that UCB hopes will compete against Astrazeneca’s blockbuster Soliris/Ultomiris franchise and Argenx’s Vyvgart suggest that these incumbents have little to worry about. UCB has taken two shots at this rare disease with zilucoplan and rozanolixizumab, the former a C5 inhibitor and the latter an FcRn MAb, with efficacy looking comparable. Argenx used a different endpoint in its myasthenia gravis programme, so a side-by-side comparison against it is harder than against Astra. But the fact that Vyvgart is off to a strong start speaks to that drug’s potential: first-quarter sales, announced last week, came in well ahead of expectations. Should UCB's contenders make it to market safety and convenience will also matter, and here the subcutaneously delivered zilucoplan appears to have an edge, with treatment-emergent adverse events occurring at a similar rate to placebo (76.7% vs 70.5%). Roza has long been considered more problematic, requiring a lengthy transfusion, while toxicity could prove a problem, with cases of severe headache emerging. Coming late to this space could ultimately be UCB’s biggest challenge, however. The company is unlikely to reach the market until late in 2023.