• Mesoblast is in a trading halt, but doesn’t expect to announce the FDA’s decision on Ryoncil until Monday
  • Approval of the stem cell treatment to treat pediatric graft-versus-host disease would be transformative for the company
  • A reason for the delay wasn’t given

Mesoblast (ASX:MSB) shareholders have a few more sleepless nights ahead of them.

The closely watched biotech went into a trading halt this morning in relation to the US Food and Drug Administration’s review of its new drug application for its award-winning drug candidate Ryoncil (remestemcel-L).

But Mesoblast told the ASX it expected to make an announcement regarding the application on Monday — not today, as many watching the company had expected.

Wednesday was the deadline for the FDA acting on Mesoblast’s application, and on Twitter, at least one punter reported they planned to stay up all night waiting on the announcement.

A reason for the delay wasn’t provided. A Mesoblast spokeswoman didn’t immediately respond to a request for comment.

Mesoblast has requested drug approval for Ryoncil to treat pediatric patients with steroid-refractory acute graft versus host disease, a serious and sometimes fatal complication of receiving bone marrow transplants.

While there’s not a huge market for the drug, there’s no approved treatment for patients under 12 — meaning Mesoblast is expected to sell its treatment for hundreds of thousands of dollars.

Approval would be transformative for the company, which only had $23.3m in revenue in FY2020.

It would also buoy Mesoblast in advance of the readouts for two phase-three studies for ailments for which there is a huge market — lower back pain and advanced chronic heart failure.

But there’s also a chance that the FDA could reject the Ryoncil application. An advisory committee voted 9-1 in August to recommend approval, but on occasion, the FDA has been known to reject the non-binding advice of its advisory committees.

The regulatory agency made it clear in some of its briefing materials for the committee it had some concerns about the drug.

Clinical trials also are underway to use Ryoncil to treat COVID-19 patients.