Argenx’s Vyvgart Fails to Hit Primary, Secondary Endpoints in Phase III Trial

Pictured: Red line graph showing a downward trend/iStock, KanawatTH

Pictured: Red line graph showing a downward trend/iStock, KanawatTH

Dutch biotech argenx was hit with a stock price drop Tuesday morning with the announcement that a subcutaneous version of its autoimmune drug Vygart Hytrulo failed to reach its endpoints in a Phase III rare bleeding disorder trial.

In Tuesday’s press release, argenx said that the topline results from its ADVANCE-SE study investigating the injectable drug Vyvgart Hytrulo in adults with primary immune thrombocytopenia (ITP) did not reach the primary endpoints of a sustained platelet count response in patients. The disease results from cells that help blood clot and can lead to bleeding and bruising.

In the study, only 13% of patients demonstrated a sustained platelet count response compared to 16.2% for those taking the placebo, demonstrating a p-value of p=0.5081. The secondary endpoints were also not reached, including international working group responder status and mean platelet count change from the baseline. However, argenx did not provide any specific figures for these metrics.

The biotech noted that it is undertaking additional analyses of the study and will present the full results at a future medical meeting. The response from Wall Street was swift as argenx’s stock price was down over 8% at the opening bell on Tuesday morning.

“This is not the outcome we had hoped for patients, but setbacks are part of pioneering a new class of medicines, and these data will provide insights into the broader understanding of FcRn and ITP,” argenx CMO Luc Truyen said in a statement.

Truyen added that the biotech remains committed to the ITP patient community, “who urgently needs additional treatment options to manage this challenging disease and continue to move forward in our deeper analysis of these results.”

Vyvgart’s foray into IPT initially looked positive as it revealed some of the Phase III data in May 2022. At the time, the trial had hit the primary endpoint, showing a “significantly higher” portion of patients—around 21%, with chronic ITP having a sustained platelet count response against a placebo with a p-value of p=0.0316.

Argenx has submitted an application for regulatory approval of Vyvgart to treat ITP in Japan, where a decision will be announced sometime in the first quarter of 2024. The drug is also being evaluated in 13 other autoimmune disorders. Topline results investigating Vyvgart for the skin disease pemphigus are expected by the end of the year, according to argenx.

The FDA approved a subcutaneous form of Vyvgart in June 2023 to treat the muscle-weakening disease generalized myasthenia gravis. The drug remains the biotech’s primary moneymaker, pulling in over $329 million in the third quarter of 2023. 

Tyler Patchen is a staff writer at BioSpace. You can reach him at tyler.patchen@biospace.com. Follow him on LinkedIn.

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