Mustang Bio partners with St Jude Children's Research Hospital to develop a gene therapy to treat Bubble Boy Syndrome

Mustang Bio (NASDAQ:MBIO) has entered into a licensing agreement with St Jude Children’s Research Hospital to develop a lentiviral-based gene therapy for children suffering from X-linked severe combined immunodeficiency, which is widely known as Bubble Boy Syndrome.

The deal provides another gene therapy treatment to Mustang’s repertoire of therapies, which mainly focus on battling cancers using CAR-T treatments.

X-SCID is a rare inherited disorder that cripples the immune system and affects about one in 50,000 to 100,000 newborns each year.

If patients don’t receive treatments, which include stem cell transplants or gene therapy, the condition is fatal in the first year of life due to the onset of severe infection.

The therapy, which Mustang has teamed up with St Jude’s to offer, involves delivering a low dose of the cancer drug busulfan before reinfusing patients with their own gene-modified blood stem cells. The regime is currently being assessed in a Phase1/2 trial evaluating infants under the age of two at St Jude, UCSF Benioff Children’s Hospital in San Francisco and Seattle Children’s Hospital.

Study marks world’s first for a lentiviral gene therapy treatment for Bubble Boy Syndrome

The study is the world’s first lentiviral gene therapy trial for infants with Bubble Boy Syndrome.

Eight patients under two years old have been treated so far, with six of them “[achieving] reconstituted immune systems within three to four months following treatment,” a company statement said.

“Our therapy has been well tolerated thus far, and none of the infants required any blood support after the low dose of busulfan,” said the study’s head Ewelina Mamcarz in a statement.

“Most importantly, we observe recovery of all cells of the immune system, which is truly an achievement over prior gene therapy trials,” she added.

In the wake of the announcement of the trial’s results, Mark Breidenbach, an analyst with Oppenheimer, is optimistic about Mustang’s prospects. He is keeping an Outperform rating on the stock as well as a US$18 price target.

“In our view, the lentiviral gene therapy program nicely complements Mustang’s portfolio of CAR-T programs and the company can leverage its in-house manufacturing capabilities to supply drug product,” Breidenbach wrote in a note to investors.

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Mustang and St Jude believe there could be as many as 1,500 patients in the US as well as a similar number in Europe with Bubble Boy Syndrome for whom allogeneic stem cell transplants don’t work well. These patients could be eligible for lentiviral gene therapy.

A subsidiary of Fortress Biotech (NASDAQ:FBIO), Mustang Bio specializes in CAR-T cell therapies, whereby a patient’s T cells are changed in a lab so they will attack cancer cells.

Mustang Bio shares were flat at US$6.46 in early afternoon trade.

Story by ProactiveInvestors