Mesoblast preps first filings for GVHD drug after phase 3 win

A bone marrow harvest in progress. (Image: Wikipedia / Navy news service)

A late-stage study of Mesoblast’s off-the-shelf stem cell therapy for acute graft-versus-host disease (GVHD) has hit its main goal, setting up an imminent U.S. filing.

The Australian biotech tested remestemcel-L in 55 children with acute GVHF refractory to steroid drugs in the open-label trial, and showed that after 28 days 69% of them had a complete or partial response to the treatment—which it says (PDF) compares favorably to a typical historical rate of around 45%.

Acute GVHD is a serious complication that is one of the leading causes of death in patients receiving donor stem cell transplants, and occurs when the donated bone marrow cells mount an immune response against the recipient’s healthy tissues. Globally, there are around 30,000 of these transplants carried out every year. If treatment with steroids doesn’t work to limit the immune reaction—estimated to occur in up to 15% of cases—the death rate can be as high as 70% within 100 days.

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50 patients in Mesoblast’s study had passed that timepoint with a survival rate of 78%, which the biotech says is “an encouraging indicator of potential longer-term benefit.” Lead investigator Joanne Kurtzberg M.D. of Duke University Medical Center said the result is “an important milestone towards delivering a potentially effective treatment for this very serious and life-threatening condition” which has no approved therapies.

Mesoblast already has fast-track status for remestemcel-L from the FDA, and said that its discussions with the agency leads it to believe the new trial results plus 180-day safety and quality of life data may be enough to file for accelerated approval in children with a label extension for adults following sometime later.

The therapy is already approved as Temcell in Japan, where it is licensed to JCR Pharma and has a reimbursement price of around $195,000.

This is the first of two important data read-outs for Mesoblast this year. The company is also waiting on results of a trial of remestemcel-L in patients with heart failure who have been implanted with a left ventricular assistance device (LVAD). The trial aims to see if a single dose of the therapy improves heart function, measured by short-term weaning off the LVAD.

Mesoblast also has a phase 3 trial of remestemcel-L in heart failure that should complete enrolment later this year and read out sometime towards the end of 2019, depending on recruitment rates. A late-stage trial in lower back pain is also in play and should be fully enrolled before year-end.