Company: MBIO
Filing Date: 2025-04-01
Form Type: 424B3
Source: 0001104659-25-030657
Chunk: 23

Company: MUSTANG BIO, INC.
Filing Date: 2025-04-01
Form: 424B3
Chunk 23
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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

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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-T Cell Investigational Products, MB100-OBS-001, that we had decided to
close that trial. As a result, further clinical development of MB-106 is currently focused solely on autoimmune diseases unless funding
and resources become available to restart the program for hematologic malignancies. Planning for the aforementioned Phase 1 investigator-sponsored
clinical trial in autoimmune diseases is in progress, with initiation anticipated in the fourth quarter of 2025.

Terminated Product Candidates (CAR-T Therapies, Gene Therapies and in vivo CAR-T)

We previously developed four additional CAR-T
product candidates licensed from City of Hope, which included MB-102 (CD123), MB-103 (HER2), MB-104 (CS1) and MB-105 (PSCA) programs.
In May 2023, we announced a series of changes resulting from a review of our portfolio of product candidates to determine the future strategy
of our programs and the proper allocation of our resources. Following this review, we determined to discontinue development of these four
programs and terminated the associated license agreements.

In