Mustang Bio, Inc. (NASDAQ: MBIO) shares skyrocketed by 260% on Thursday at the opening bell after the Company announced on Wednesday after it entered into an agreement with St. Jude Children’s Research Hospital to develop a gene therapy treatment.
Mustang and St. Jude are partnering to commercialize lentiviral gene therapy used to treat XSCID or more commonly known as “bubble boy” disease.
The agreements comes after Mustang’s Phase 1 and 2 clinical trials which are evaluating the safety and efficacy of a lentiviral vector to transfer a normal copy of the IL2RG gene to the bone marrow stems cells in newly diagnosed children under the age of 2. The published data covers eight infants with XSCID who were treated at St. Jude and at UCSF Benioff Children’s Hospital and followed for a median of 16.4 months.
“The results have been very good thus far. We’ve been able to restore a full immune system pretty quickly,” Ewelina Mamcarz, M.D., assistant member at St. Jude said. “All of these patients were able to come off of isolation and they’ve returned home with immune systems that were fully functional. We had patients come to us with very severe infections and they cleared them through the emergence of this newly developed immune system.”
Mustang reported that Bone marrow harvest, busulfan conditioning and cell infusion were well tolerated. Furthermore, in seven of the eight cases, normalization of CD3+, CD4+ and CD4+ naïve T-cell and natural killer cell numbers occurred within three to four months after treatment, accompanied by vector marking in T, B, NK and myeloid cells and marrow progenitors, according to its press release.
The eighth infant had insufficient T cells initially, but Mustang said that the normalization of T cells occurred following an unconditioned boost of gene-corrected cells, and the patient is progressing favorably.
Martina Sersch, M.D., Ph.D., Chief Medical Officer of Mustang, said, “We are extremely encouraged by the Phase 1/2 clinical data published in the New England Journal of Medicine. They underscore the potential of MB-107 as a novel approach and potentially curative treatment option for newly diagnosed infants with XSCID. We are excited to continue working with St. Jude to evaluate MB-107 in this clinical trial, and we look forward to transferring the IND to Mustang by the end of this year, after which patients’ cells from all three participating clinical trial sites will be processed in our Worcester, Mass., facility.”