The Dutch biotech argenx has big plans to develop its drug Vyvgart in more than a dozen autoimmune diseases. But failures in two pivotal studies threw a wrench in that strategy late last year.
Now, it’s taking another shot at one of those diseases where it fell short. It will run a new trial in primary immune thrombocytopenia, or ITP, a rare condition in which a person’s immune system attacks and destroys their platelets, leaving them fatigued and susceptible to bleeding.
“We have reached an agreement with the FDA on a relatively small, relatively concise, confirmatory study for Vyvgart in ITP, which if successful, would satisfy requirements for approval,” CEO Tim Van Hauwermeiren told Endpoints News in an interview ahead of the company’s earnings announcement Thursday.
In Japan, Vyvgart is already approved as an intravenous infusion for ITP, based on positive results from one study. But the injectable version’s failed study in November cast doubt on the drug’s future in the US. Van Hauwermeiren said he’s now ditching the injectable option for the disease to focus on getting the infused drug approved.
The news comes a week after Van Hauwermeiren doubled down on the broad potential of Vyvgart at the company’s R&D day in New York. He even said that argenx is working on a sequel drug that it wants to test in conditions from which it won’t have time to fully profit before the Inflation Reduction Act’s drug pricing regulations may kick in.
Even though ITP is a rare disease, Vyvgart’s approval for the condition could mark a significant windfall for the company. Argenx estimates that there are roughly 60,000 to 70,000 people with ITP in the US, with one-third of them struggling to control their disease using older medications.
Van Hauwermeiren said the market is “very comparable” to myasthenia gravis, for which Vyvgart is already approved. The company charges roughly $225,000 a year for those patients. In its quarterly earnings report on Thursday, argenx reported $478 million in Vyvgart sales in the second quarter of the year, up from $269 million in the same quarter last year.
Last year’s failure in ITP was a major shock for argenx. The disease is one of three that helped launch the company’s thesis that a single drug for eliminating autoantibodies could work for many conditions. But when it failed to beat a placebo in its own Phase 3, the company’s stock fell 10%.
Van Hauwermeiren said he’s confident that there’s nothing wrong with the injectable form, called Vyvgart Hytrulo, which is approved for another disease called myasthenia gravis. He blamed the failure in ITP on “specific countries” and “specific sites” that were not as disciplined in following the study protocols — although he wouldn’t name them.
“These patients come in with very low platelet counts,” Van Hauwermeiren said. “And depending on geography, you see peaks in platelet counts in placebo patients, which are not explainable unless they are using background medication.”
The new ITP study will begin by the end of the year and, Van Hauwermeiren said it will avoid locales that he believes gave the company trouble last time around. The trial will be less than half the size of the previous study, which was just over 200 patients, and use a simpler primary endpoint of cumulative platelet count instead of a sustained platelet count.