The primary endpoint of a sustained platelet count response was not met (p=0.5081); 13.7% (17/124) of treated patients demonstrated a sustained platelet count response compared to 16.2% (11/68) of placebo patients.

Secondary endpoints were not met, including additional endpoints on International Working Group (IWG) responder status and mean platelet count change from baseline.

ADVANCE-IV formed the basis of the regulatory submission for approval of Vyvgart IV for ITP in Japan, where a decision is expected in the first quarter of 2024.

William Blair writes that the outright failure across endpoints is surprising.

As ADVANCE-SC performed worse than ADVANCE-IV, it raises the question of whether the pharmacokinetics of Vyvgart SC were suboptimal in ITP, but even achieving a 22% response rate would not have resulted in a positive trial given the level of placebo.

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