MUSTANG BIO, INC.
For the period ended Sep 30, 2025. Filed Nov 7, 2025.
View on SEC.govAbout this filing
A company's report for each of its first three quarters. The financial statements are not audited. It shows how the business has moved since the last annual report, and what management says changed.
Sep 30, 2025 · Filed Nov 7, 2025
MBIO$0.39+0.2%Stored close · as of Nov 6, 2026
What changed in Management’s Discussion and Analysis?
Read the current filingPrevious report: 10-Q
Period ended 2025-06-30; filed 2025-08-08.
0001558370-25-010920
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsCurrent report: 10-Q
Period ended 2025-09-30; filed 2025-11-07.
0001104659-25-108468
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsThe baseline is this issuer’s latest earlier reporting period of the same form that was filed before the current report. A previous 10-Q is a different quarter, not a year-over-year comparison. Amendments are excluded.
Compared 81 previous paragraphs and 78 current paragraphs.
49 unchanged; 23 reworded; 5 added; 5 removed; 4 previous and 1 current paragraphs rearranged.
Tables are not compared: 18 previous and 14 current tables excluded. Dates, whitespace, punctuation and numbering changes are ignored; changes to financial figures remain significant.
A changed paragraph is not evidence that risk increased or decreased. An unchanged paragraph does not establish that risk stayed the same.
Added paragraphs (5)
Current report
In September 2025, we received notice from Fred Hutch of its intent to terminate the CD20 License for cause in connection with unpaid patent expenses and maintenance fees. A 90-day cure period is applicable under the CD20 License. We intend to negotiate the terms of an arrangement with Fred Hutch pursuant to which the CD20 License is terminated (together with related agreements) in exchange for potential consideration remunerable to us.
Current report
We are currently pursuing the development of MB-106, in collaboration with Fred Hutch, for autoimmune diseases. As described above, however, we are in ongoing discussions with Fred Hutch regarding potential termination of this program.
Current report
In July 2025, the remaining approximately 0.5 million of the Pre-Funded Warrants and approximately 2.4 million of the Series C-2 Warrants were exercised. In connection with these exercises, the Company received approximately $7.1 million in proceeds and issued approximately 2.9 million shares of its common stock. As of September 30, 2025, all of the Series C-1 Warrants and 284,452 of the Series C-2 Warrants remain outstanding.
Current report
For the three months ended September 30, 2025, and 2024, other income was $0.2 million and $47,000, respectively. The increase of approximately $0.1 million reflects an increase in interest income.
Current report
Comparison of the Nine Months Ended September 30, 2025 and 2024
Removed paragraphs (5)
Previous report
Currently, we are focused on the development of MB-106, in collaboration with Fred Hutch, for autoimmune diseases. We are in planning stages for a proof-of-concept investigator-sponsored clinical trial and actively evaluating potential indications in which MB-106 may be most effective and serve a patient population with high unmet need with a potential trial initiation in the first quarter of 2026.
Previous report
We have also previously been granted Regenerative Medicine Advanced Therapy (“RMAT”) designation by the FDA for the treatment of relapsed or refractory CD20-positive Waldenstrom macroglobulinemia and follicular lymphoma based on clinical data in both indications disclosed previously.
Previous report
Comparison of the Six Months Ended June 30, 2025 and 2024
Previous report
Asset Impairment
Previous report
For the six months ended June 30, 2025, and 2024, total other income was $0.2 million and $0.4 million, respectively. The decrease of approximately $0.2 million reflects a decrease of other income of approximately $0.3 million related to the non-repeat gain on the termination of the Mercantile Center lease in June 2024 offset by an increase in interest income of approximately $0.2 million.
Reworded paragraphs (23)
Previous wording
We are developing CAR T therapy for solid tumors in partnership with COH targeting IL13Rα2 (MB-101). In addition, we have partnered with Nationwide on the development of a herpes simplex virus type 1 (“HSV-1”) oncolytic virus (MB-108) in order to enhance the activity of MB-101 for the treatment of patients with high-grade malignant brain tumors. A Phase 1 clinical trial sponsored by COH for MB-101 (ClinicalTrials.gov Identifier: NCT02208362) has completed the treatment phase and patients continue to be assessed for long-term safety. A Phase 1 clinical trial sponsored by the University of Alabama at Birmingham (“UAB”) for MB-108 (ClinicalTrials.gov Identifier: NCT03657576) has also completed the treatment phase and patients continue to be assessed for long-term safety. In October 2023, we announced that the FDA accepted our IND application for the combination of MB-101 and MB-108 – which is referred to as MB-109 – for the treatment of patients with IL13Rα2+ relapsed or refractory glioblastoma (“GBM”) and high-grade astrocytoma. Pursuant to termination of the lease for our cell processing center in Worcester, MA, we are exploring with COH and Nationwide the possibility of initiating this clinical trial as an investigator-sponsored single-institution study at COH in the first quarter of 2026.
Current wording
We are developing CAR T therapy for solid tumors in partnership with COH targeting IL13Rα2 (MB-101). In addition, we have partnered with Nationwide on the development of a herpes simplex virus type 1 (“HSV-1”) oncolytic virus (MB-108) in order to enhance the activity of MB-101 for the treatment of patients with high-grade malignant brain tumors. A Phase 1 clinical trial sponsored by COH for MB-101 (ClinicalTrials.gov Identifier: NCT02208362) has completed the treatment phase and patients continue to be assessed for long-term safety. A Phase 1 clinical trial sponsored by the University of Alabama at Birmingham (“UAB”) for MB-108 (ClinicalTrials.gov Identifier: NCT03657576) has also completed the treatment phase and patients continue to be assessed for long-term safety. In October 2023, we announced that the FDA accepted our IND application for the combination of MB-101 and MB-108 – which is referred to as MB-109 – for the treatment of patients with IL13Rα2+ relapsed or refractory glioblastoma (“GBM”) and high-grade astrocytoma. Pursuant to termination of the lease for our cell processing center in Worcester, MA, we are exploring with COH and Nationwide the possibility of initiating this clinical trial as an investigator-sponsored single-institution study at COH in the second quarter of 2026.
Previous wording
We are also developing a CAR T therapy for hematologic malignancies and autoimmune diseases in partnership with Fred Hutch targeting CD20 (MB-106). In May 2021, we announced that the U.S. Food and Drug Administration (“FDA”) accepted our IND Application for MB-106. As of June 30, 2025, 53 patients have been treated in an ongoing Phase 1 clinical trial sponsored by Fred Hutch (ClinicalTrials.gov Identifier: NCT03277729) and 20 patients have been treated in the Phase 1 clinical trial sponsored by us (ClinicalTrials.gov Identifier: NCT05360238). Each clinical trial has completed its respective treatment phase, and patients continue to be assessed for long-term safety. Pursuant to termination of the lease for our cell processing center in Worcester, MA, we are exploring with Fred Hutch the possibility of initiating a Phase 1 trial in autoimmune diseases as an investigator-sponsored single-institution study at Fred Hutch in the first quarter of 2026.
Current wording
We are also developing a CAR T therapy for hematologic malignancies and autoimmune diseases in partnership with Fred Hutch targeting CD20 (MB-106) pursuant to a license agreement originally executed with Fred Hutch in 2017 (the “CD20 License”). In May 2021, we announced that the U.S. Food and Drug Administration (“FDA”) accepted our IND Application for MB-106. As of June 30, 2025, 53 patients have been treated in an ongoing Phase 1 clinical trial sponsored by Fred Hutch (ClinicalTrials.gov Identifier: NCT03277729) and 20 patients have been treated in the Phase 1 clinical trial sponsored by us (ClinicalTrials.gov Identifier: NCT05360238). Each clinical trial has completed its respective treatment phase, and patients continue to be assessed for long-term safety.
Previous wording
We are currently exploring with COH and Nationwide the possibility of conducting an investigator-sponsored single-institution trial under the COH IND to treat patients with IL13Rα2+ recurrent GBM and high-grade astrocytoma with MB-109 that could potentially be initiated in the first quarter of 2026. Because cell processing for MB-101 will revert back to COH – where the product continues to be manufactured today for other investigator-sponsored clinical trials being conducted by COH in malignant brain tumors (ClinicalTrials.gov Identifiers: NCT04003649, NCT04661384, NCT04510051), we believe that it is reasonable to assume that the FDA will not require a lead-in cohort, wherein a cohort of patients would have to be treated with MB-101 alone prior to treatment of subsequent cohorts with the combination of MB-108 followed by MB-101. Should this, indeed, be the case, the first patient enrolled will receive combination therapy, which will represent a considerable savings of time and money – as well as afford the potential benefit of both therapies to every patient treated on study.
Current wording
We are currently exploring with COH and Nationwide the possibility of conducting an investigator-sponsored single-institution trial under the COH IND to treat patients with IL13Rα2+ recurrent GBM and high-grade astrocytoma with MB-109 that could potentially be initiated in the second quarter of 2026. Because cell processing for MB-101 will revert back to COH – where the product continues to be manufactured today for other investigator-sponsored clinical trials being conducted by COH in malignant brain tumors (ClinicalTrials.gov Identifiers: NCT04003649, NCT04661384, NCT04510051), we believe that it is reasonable to assume that the FDA will not require a lead-in cohort, wherein a cohort of patients would have to be treated with MB-101 alone prior to treatment of subsequent cohorts with the combination of MB-108 followed by MB-101. Should this, indeed, be the case, the first patient enrolled will receive combination therapy, which will represent a considerable savings of time and money – as well as afford the potential benefit of both therapies to every patient treated on study.
Previous wording
The Pre-Funded Warrants have an exercise price of $0.0001 per share, were exercisable immediately upon issuance and will expire when exercised in full. Each Warrant has an exercise price of $3.01 per share and will be exercisable beginning on the effective date of the Warrant Stockholder Approval. The Series C-1 warrants will expire five years from the Warrant Stockholder Approval and the Series C-2 warrants will expire twenty-four months from the Warrant Stockholder Approval. The Warrant Stockholder Approval was obtained on March 23, 2025.
Current wording
The Pre-Funded Warrants had an exercise price of $0.0001 per share, were exercisable immediately upon issuance and will expire when exercised in full. Each Warrant has an exercise price of $3.01 per share and will be exercisable beginning on the effective date of the Warrant Stockholder Approval. The Series C-1 warrants will expire five years from the Warrant Stockholder Approval and the Series C-2 warrants will expire twenty-four months from the Warrant Stockholder Approval. The Warrant Stockholder Approval was obtained on March 23, 2025.
Previous wording
During the six months ended June 30, 2025, we issued approximately 54,000 shares of common stock at an average price of $11.55 for gross proceeds of $0.6 million under the ATM Agreement. In connection with these sales, we paid aggregate fees of approximately $27,000.
Current wording
During the nine months ended September 30, 2025, we issued approximately 54,000 shares of common stock at an average price of $11.55 for gross proceeds of $0.6 million under the ATM Agreement. In connection with these sales, we paid aggregate fees of approximately $27,000.
Previous wording
judgment in determining the appropriateness of acceptable accounting principles and methods of application in diverse and complex economic activities. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of expenses, assets and liabilities, and related disclosure of contingent assets and liabilities. We base our estimates on historical experience and other assumptions that we believe are reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions.
Current wording
Our discussion and analysis of our financial condition and results of operations are based on our financial statements, which we have prepared in accordance with accounting principles generally accepted in the United States. Applying these principles requires our judgment in determining the appropriateness of acceptable accounting principles and methods of application in diverse and complex economic activities. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of expenses, assets and liabilities, and related disclosure of contingent assets and liabilities. We base our estimates on historical experience and other assumptions that we believe are reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions.
Previous wording
During the six months ended June 30, 2025, there were no new accounting pronouncements or updates to recently issued accounting pronouncements disclosed in the 2024 Form 10-K that are expected to materially affect our present or future financial statements.
Current wording
During the nine months ended September 30, 2025, there were no new accounting pronouncements or updates to recently issued accounting pronouncements disclosed in the 2024 Form 10-K that are expected to materially affect our present or future financial statements.
Previous wording
For the three months ended June 30, 2025 and 2024, research and development expenses were approximately $0.1 million and $4.4 million, respectively. The decrease of approximately $4.3 million is primarily attributed to actions taken in 2024, including the reduction
Current wording
For the three months ended September 30, 2025 and 2024, research and development expenses were approximately $(0.3) million and $0.1 million, respectively. The decrease of approximately $0.4 million is primarily attributed to:
Previous wording
For the three months ended June 30, 2025, and 2024, general and administrative expenses were $0.8 million and $1.5 million, respectively. The decrease of approximately $0.7 million is primarily attributed to a $0.3 million decrease in personnel related expenses, $0.2 million decrease in non-cash stock-based compensation expenses, including the equity fee to Fortress, $0.1 million decrease in consulting costs and $0.1 million decrease in professional services including legal and patent protection expenses.
Current wording
For the three months ended September 30, 2025, and 2024, general and administrative expenses were $1.0 million and $1.4 million, respectively. The decrease of approximately $0.4 million is primarily attributed to a $0.1 million decrease in personnel related expenses, $0.2 million decrease in legal and patent protection expenses, $0.1 million decrease in consulting costs and $0.1 million decrease in other expenses, offset by $0.1 million increase in non-cash stock-based compensation expenses, primarily the equity fee to Fortress.
Previous wording
For the six months ended June 30, 2025 and 2024, research and development expenses were approximately $(0.9) million and $8.2 million, respectively. The decrease of approximately $9.0 million is primarily attributed to actions taken in 2024, including the reduction in the workforce, closing the MB-106 clinical trial, and the termination of our transaction with uBriGene. These activities resulted in decreases in the following expenses:
Current wording
For the nine months ended September 30, 2025 and 2024, research and development expenses were approximately $(1.2) million and $8.2 million, respectively. The decrease of approximately $9.4 million is primarily attributed to actions taken in 2024, including the reduction in the workforce, closing the MB-106 clinical trial, and the termination of our transaction with uBriGene. These activities resulted in decreases in the following expenses:
Previous wording
Additionally, we have been actively negotiating settlements of aged payables, and recognized savings of approximately $0.8 million and recognized a net gain of approximately $0.4 million due to the termination of the Plantation Street Facility lease, which resulted in a credit for research and development expenses for the six months ended June 30, 2025. This credit is not indicative of our research and development expenses going forward.
Current wording
Additionally, we have been actively negotiating settlements of aged payables, and recognized savings of approximately $1.4 million and recognized a net gain of approximately $0.4 million due to the termination of the Plantation Street Facility lease, which resulted in a credit for research and development expenses for the nine months ended September 30, 2025. This credit is not indicative of our research and development expenses going forward.
Previous wording
For the three months ended June 30, 2024, we incurred impairment charges of $2.6 million attributable to our assessment of the recoverability of the asset group consisting of leasehold improvements and associated right-of-use asset. No impairment was recorded in the three months ended June 30, 2025.
Current wording
For the nine months ended September 30, 2024, we incurred impairment charges of $2.6 million attributable to our assessment of the recoverability of the asset group consisting of leasehold improvements and associated right-of-use asset. No impairment was recorded in the nine months ended September 30, 2025.
Previous wording
For the six months ended June 30, 2025, and 2024, general and administrative expenses were $2.0 million and $3.0 million, respectively. The decrease of approximately $1.0 million is primarily attributed to a $0.2 million decrease in personnel costs, $0.3 million decrease in legal and patent protection expenses, $0.3 million decrease in consulting expenses, and a $0.2 million decrease across various other general and administrative expenses.
Current wording
For the nine months ended September 30, 2025, and 2024, general and administrative expenses were $3.0 million and $4.4 million, respectively. The decrease of approximately $1.4 million is primarily attributed to a $0.4 million decrease in personnel costs, $0.5 million decrease in legal and patent protection expenses, $0.4 million decrease in consulting expenses, and $0.3 million decrease across various other general and administrative expenses, offset by $0.2 million increase innon-cash stock-based compensation expenses, primarily the equity fee to Fortress.
Previous wording
For the three months ended June 30, 2025, and 2024, other income was $0.1 million and $0.3 million, respectively. The decrease of approximately $0.2 million reflects a decrease in other income of approximately $0.3 million related to the non-repeat gain on the termination of the Mercantile Center lease in June 2024, offset by an increase in interest income of approximately $0.1 million.
Current wording
Other income for the nine months ended September 30, 2025, was $0.4 million relating to interest income. Other income for the nine months ended September 30, 2024, was $0.3 million relating to the non-repeat gain on the termination of the Mercantile Center lease in June 2024 and $0.1 million of interest income.
Previous wording
At June 30, 2025, we had cash and cash equivalents of $12.7 million. We have funded our operations to date primarily with the proceeds from various public and private offerings of our common stock. We have incurred substantial operating losses and expect to continue to incur significant operating losses for the foreseeable future and may never become profitable. We will continue to seek additional funding through corporate partnerships and capital markets fundraising. As of June 30, 2025, we had an accumulated deficit of $397.6 million.
Current wording
At September 30, 2025, we had cash and cash equivalents of $19.0 million. We have funded our operations to date primarily with the proceeds from various public and private offerings of our common stock. We have incurred substantial operating losses and expect to continue to incur significant operating losses for the foreseeable future and may never become profitable. We will continue to seek additional funding through corporate partnerships and capital markets fundraising. As of September 30, 2025, we had an accumulated deficit of $398.1 million.
Previous wording
During the three and six months ended June 30, 2025, there were no material changes in our contractual obligations and commitments, as described in our 2024 Form 10-K.
Current wording
During the three and nine months ended September 30, 2025, there were no material changes in our contractual obligations and commitments, as described in our 2024 Form 10-K.
Previous wording
Cash Flows for the Six Months Ended June 30, 2025 and 2024
Current wording
Cash Flows for the Nine Months Ended September 30, 2025 and 2024
Previous wording
Net cash used in operating activities was $2.7 million for the six months ended June 30, 2025, compared to $7.7 million for the six months ended June 30, 2024.
Current wording
Net cash used in operating activities was $3.5 million for the nine months ended September 30, 2025, compared to $9.4 million for the nine months ended September 30, 2024.
Previous wording
Net cash used in operating activities for thesix months ended June 30, 2025, was primarily due to approximately $0.9 million in net loss, $1.8 million change in operating assets and liabilities, and $0.4 million gain on the termination of the Plantation Street Facility lease, partially offset by $0.3 million of non-cash items, primarily related to the $0.2 million equity fee to Fortress for financing activity.
Current wording
Net cash used in operating activities for thenine months ended September 30, 2025, was primarily due to approximately $1.4 million in net loss, $0.9 million change in operating assets and liabilities, $1.3 million non-cash savings from the settlement of payables and $0.4 million gain on the termination of the Plantation Street Facility lease, partially offset by $0.5 million of non-cash items, primarily related to the $0.4 million equity fee to Fortress for financing activity and $0.1 million of non-cash stock based compensation expenses.
Previous wording
Net cash used in operating activities for thesix months ended June 30, 2024, was primarily due to approximately$13.4 million in net loss, partially offset by $5.7 million of non-cash items, primarily related to the $2.6 million asset impairment charge and a $3.1 million change in operating assets and liabilities.
Current wording
Net cash used in operating activities for thenine months ended September 30, 2024, was primarily due to approximately$14.8 million in net loss, partially offset by $2.8 million of non-cash items, primarily related to the $2.6 million asset impairment charge, and a $2.6 million positive change in operating assets and liabilities.
Previous wording
During thesix months ended June 30, 2025, net cash provided by investing activities was $1.2 million, which primarily reflects the proceeds from the sale of equipment to AbbVie. No cash was used in or provided by investing activities during the six months ended June 30, 2024.
Current wording
During thenine months ended September 30, 2025, net cash provided by investing activities was $1.2 million, which primarily reflects the proceeds from the sale of equipment to AbbVie. No cash was used in or provided by investing activities during the nine months ended September 30, 2024.
Previous wording
Net cash provided by financing activities was $5.3 million during the six months ended June 30, 2024, primarily reflecting proceeds from the May 2024 Offering and June 2024 Offering.
Current wording
Net cash provided by financing activities was $14.5 million during thenine months ended September 30, 2025, primarily reflecting the proceeds from the February 2025 Equity Offering, the ATM Agreement and the July 2025 warrant exercises.
Previous wording
Net cash provided by financing activities was $7.4 million during thesix months ended June 30, 2025, primarily reflecting the proceeds from the February 2025 Equity Offering and the ATM Agreement.
Current wording
Net cash provided by financing activities was $6.3 million during the nine months ended September 30, 2024, primarily reflecting proceeds from the May 2024 Offering, June 2024 Offering and the ATM Agreement.
Rearranged current paragraphs (1)
Current report — wording carried from elsewhere
Additionally, we have been actively negotiating settlements of aged payables, and recognized savings of approximately $0.6 million, which resulted in a credit for research and development expenses during the three months ended September 30, 2025. This credit is not indicative of our research and development expenses going forward.
Rearranged previous paragraphs (4)
Previous report — wording carried elsewhere
Our discussion and analysis of our financial condition and results of operations are based on our financial statements, which we have prepared in accordance with accounting principles generally accepted in the United States. Applying these principles requires our
Previous report — wording carried elsewhere
in the workforce, closing the MB-106 clinical trial, and the termination of our transaction with uBriGene. These activities resulted in decreases in the following expenses:
Previous report — wording carried elsewhere
Additionally, we have been actively negotiating settlements of aged payables, and recognized savings of approximately $0.1 million.
Previous report — wording carried elsewhere
For the six months ended June 30, 2024, we incurred impairment charges of $2.6 million attributable to our assessment of the recoverability of the asset group consisting of leasehold improvements and associated right-of-use asset. No impairment was recorded in the six months ended June 30, 2025.