Mustang Bio Sells Manufacturing Facility, Scraps and Delays Programs to Conserve Cash

Rare Daily Staff

Mustang Bio said it was selling its manufacturing facility, and discontinuing and delaying programs as part of an effort to extend its cash runway.

Mustang entered into a partnership with uBriGene Biosciences, the U.S. subsidiary of uBriGene Group, a leading cell and gene therapy contract development and manufacturing organization, which includes the sale of the company’s development, manufacturing, and analytical testing facility in Worcester, Massachusetts to uBriGene.

Under the terms of an asset purchase agreement between Mustang and uBriGene, uBriGene will acquire Mustang’s state-of-the-art clinical- and commercial-scale cell and gene therapy manufacturing facility for a total consideration of $11 million, including $6 million payable upfront plus an additional $5 million payable upon Mustang raising $10 million in gross proceeds from equity raises following the closing of the transaction.

Subject to closing, the parties will enter into a manufacturing supply agreement, under which uBriGene will manufacture Mustang’s lead product candidates, including continuing to support MB-106 manufacturing for the ongoing multi-center phase 1/2 trial.

“We believe that this strategic partnership with uBriGene will meet our portfolio manufacturing needs to reach critical upcoming data inflection points, while extending our cash runway,” said Manuel Litchman, president and CEO of Mustang. “While we are optimizing our resources at Mustang, we look forward to continuing to work with many of our colleagues in this new capacity, as our CDMO.”

After a review of its portfolio of product candidates to determine the future strategy of its programs and the proper allocation of its resources, Mustang will discontinue development of its MB-102, its CD123-targeted CAR T cell therapy, as well as its HER2-, CS1- and PSCA-targeted CAR T cell therapy programs, comprising a portion of the company’s portfolio of CAR T cell therapies being developed by Mustang Bio in partnership with City of Hope.

Mustang will continue to work with Fred Hutchinson Cancer Center to develop MB-106 (CD20-targeted CAR T cell therapy) and with Mayo Clinic to develop its in vivo CAR T platform technology. Mustang will also continue to work with City of Hope and with Nationwide Children’s Hospital on the development of MB-109 (MB-101 CAR T cell therapy targeting IL13Rα2 on malignant glioma cells + MB-108 oncolytic virus to potentially make these tumors more susceptible to killing by the CAR-T cells).

Additionally, based on a review of the data from the investigator-sponsored clinical trials of the gene therapy for X-linked severe combined immunodeficiency (XSCID) that has been licensed to Mustang Bio, enrollment to these trials has been paused. The company awaits data from new investigator-sponsored trials being planned by its partners that will test a modified version of the current lentiviral vector prior to initiating multicenter Mustang-sponsored trials in both the newborn and previously transplanted patient populations. No safety concerns in the trials utilizing the current vector have been noted to date and no insertional mutagenesis or malignancy has been detected in either of the two investigator-sponsored trials. However, Mustang made the decision to delay initiating its own sponsored trials out of an abundance of caution. The delayed start of Mustang’s multicenter trials for XSCID will allow the company to utilize the safest known vector available in its clinical trials and reduce Mustang’s near-term operating expense.

In addition, in 2023 the company plans to treat a second RAG1-SCID patient with it MB-110 LV-RAG1 ex vivo lentiviral gene therapy in the ongoing investigator-sponsored phase 1/2 multicenter clinical trial taking place in Europe.

“Upon completion of a thorough, strategic review of our portfolio of CAR T and gene therapies, it was determined that Mustang’s resources should be focused and allocated to benefit our lead clinical-stage CAR T programs, which could provide potential curative treatment options for certain hematologic cancers and solid tumors, supported by data-to-date,” said Litchman.

Mustang previously reported that MB-106 continues to demonstrate high efficacy and a favorable safety profile in a phase 1 investigator-sponsored trial at Fred Hutch, with an overall response rate of 96 percent and complete response rate of 75 percent in a wide range of hematologic malignancies, including Waldenstrom macroglobulinemia (WM). Mustang plans to treat patients with WM in the phase 1 portion of its multicenter MB-106 clinical trial to support a fast-to-market phase 2 strategy for this indication, with the first pivotal phase 2 WM patient potentially to be treated in the first quarter of 2024.

“Concentrating our priorities and postponing the initiation of the XSCID pivotal trials, along with maintaining a reduced headcount, reduces Mustang’s burn and extends our cash runway,” said Litchman. “This allows Mustang to allocate more resources to advance our lead clinical-stage programs and potentially expedite the achievement of several near-term milestones across our portfolio of product candidates for difficult-to-treat cancers.”

Photo: Manuel Litchman, president and CEO of Mustang