Company: MBIO
Filing Date: 2025-04-01
Form Type: 424B3
Source: 0001104659-25-030657
Chunk: 121

Company: MUSTANG BIO, INC.
Filing Date: 2025-04-01
Form: 424B3
Chunk 121
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ab or dexamethasone.

In March 2024, we announced plans to collaborate
with Fred Hutch for a proof-of-concept Phase 1 investigator-sponsored clinical trial evaluating MB-106 in autoimmune diseases.

In March 2024, we were granted the Regenerative
Medicine Advanced Therapy (“RMAT”) designation by the FDA for the treatment of relapsed or refractory CD20 positive WM and
FL, based on potential improvement in response as seen in clinical data to date. Drugs eligible for RMAT designation are those intended
to treat, modify, reverse or cure a serious or life-threatening disease or condition, and that present preliminary clinical evidence indicating
the drug has the potential to address unmet medical needs for such disease or condition. RMAT designation provides regenerative medicine
advanced therapy products with the same benefits to expedite the development and review of a marketing application that are available
to drugs that receive Breakthrough Therapy Designation.

In June 2024, we announced that updated data for
MB-106 in the Phase 1/2 Fred Hutch investigator-sponsored trial showed a favorable safety and efficacy profile in 10 patients with WM.
There was an overall response rate (“ORR”) of 90% with durable responses observed, including three complete responses (“CR”),
two very good partial responses (“VGPR”), and four partial responses (“PR”). One of the patients who achieved
a CR remained in remission for 31 months, with an immunoglobulin M (IgM) level that decreased rapidly to the normal range after treatment
with MB-106 and remained normal since. Patients had a median of nine prior lines of therapy, and only one patient started additional anti-WM
treatment after being treated with MB-106. From a safety perspective, CRS occurred in nine patients: five patients with grade 1 and four
patients with grade 2. One patient experienced grade 1 ICANS. No grade 3 or 4 CRS or grade 2, 3 or 4 ICANS was observed, despite dose
escalation.

In May 2024, we informed the clinical sites participating
in the Mustang-sponsored Phase 1/2 study in non-Hodgkin lymphoma and chronic lymphocytic leukemia, MB106-CD20-001, that we had decided
to close the trial. In June 2024, we similarly informed the clinical sites participating in the Mustang-sponsored Long-term Follow-up
Study in Patients Previously Treated with Mustang Bio, Inc. CAR