FDA lifts clinical hold on Mustang Bio's lentiviral gene therapy, paving the way for quick jump into pivotal trial
Things were looking good for Mustang Bio’s MB-107 gene therapy program. By early September, it had nabbed both rare pediatric disease and orphan drug designations, adding to the regenerative medicine advanced therapy designation it already scored at the FDA. It all boded well for the pivotal trial they were looking to start in newly diagnosed infants with X-linked severe combined immunodeficiency.
There was just a problem: The FDA had put a clinical hold on that trial in June.
Six months after execs first alerted investors to the hold, Mustang said they’ve finally been cleared to proceed with dosing.
Regulators lifted the hold on the pivotal Phase II trial on Jan. 28 after reviewing a comprehensive package on chemistry, manufacturing and controls (CMC) — which was what raised concerns in the first place — submitted in late December, Mustang added.
“The clinical outcomes observed in XSCID patients in the ongoing Phase 1/2 clinical trials continue to be encouraging,” CEO Manuel Litchman said in a statement. “It is especially gratifying to see the consistent safety and efficacy of our lentiviral vector over the course of more than eight years since the first patient was treated at NIAID in 2012.”
Mustang plans to start the trial in 2021, enrolling 10 patients whose data would be compiled with those from the 15 already treated in the current study. It’s previously noted that investigators were continuing to accrue particpants while waiting for the hold to lift.
After treatment with MB-107, a one-time therapy delivering the IL2RG gene in a lentiviral vector, the 25 patients will be compared with 25 “matched historical control patients who have undergone hematopoietic stem cell transplantation” — the current treatment of choice that, while theoretically curative, can still leave patients vulnerable to infections.
The program now being developed by Mustang came from St. Jude Children’s Research Hospital, but the approach has been tested for almost two decades either as an alternative or followup to HSCT.
A second program, dubbed MB-207, is targeting that population who’s received transplants.
The pivotal trial will be comparing event-free survival between the two groups. Although it’s starting later than originally expected, the company says it still anticipates topline data in the second half of 2022.
Social: Manuel Litchman, PR Newswire