8-K: Marker Therapeutics Reports Strong Phase 1 Lymphoma Data

Marker Therapeutics announced encouraging Phase 1 APOLLO study results for MT-601 in relapsed lymphoma, showing high objective response rates and a favorable safety profile.

Summary

• The Phase 1 APOLLO study of MT-601, a Multi-Antigen Recognizing (MAR)-T cell product, in patients with relapsed B-cell lymphoma demonstrated promising safety and efficacy.
• In Non-Hodgkin Lymphoma (NHL) patients (n=12 assessed), an Objective Response Rate (ORR) of 66% was observed, with 50% achieving a Complete Response (CR).
• NHL patients had undergone a median of 5 prior lines of therapy, including anti-CD19 CAR-T cells (n=9) and bispecific antibodies (n=4).
• Durable responses were noted in NHL patients, ranging from 3 to 24 months, with 5 patients showing continued response at 6 months and 3 patients at 12 months.
• In Hodgkin Lymphoma (HL) patients (n=9 assessed), an ORR of 78% was achieved, with 11% demonstrating a CR.
• A favorable safety profile was observed across all evaluated doses (100x10^6-400x10^6 cells), with no Dose Limiting Toxicities (DLTs) or immune-effector cell associated neurotoxicity syndrome (ICANS) reported.
• Only two Grade 1 cytokine release syndrome (CRS) events (fever) were reported, requiring no treatment.
• The Safety Review Committee (SRC) cleared the pre-specified maximum dose (400x10^6 cells) for the dose expansion phase on June 17, 2025.
• The dose expansion phase will enroll patients with Diffuse Large B Cell Lymphoma (DLBCL) who have relapsed after or are ineligible for CAR-T cell therapy.
• Cash and cash equivalents totaled $11.8 million as of June 30, 2025, with a projected cash runway into Q2 2026, assuming no additional grant funds are received.
• Marker Therapeutics has received over $30 million in non-dilutive funding from NIH, FDA, and CPRIT to date.

Sentiment

Score: 8

Explanation: The clinical results for MT-601 in the Phase 1 APOLLO study are highly encouraging, demonstrating strong efficacy and a favorable safety profile in a difficult-to-treat patient population. The advancement to dose expansion and the potential for MT-601 to address a significant unmet medical need are strong positives. However, the early stage of the trial and the limited cash runway into Q2 2026 introduce some financial uncertainty.

Positives

• High objective response rates in heavily pre-treated lymphoma patients: 66% ORR and 50% CR in NHL, and 78% ORR and 11% CR in HL.
• Favorable safety profile with no DLTs or ICANS, and only two Grade 1 CRS events that did not require treatment.
• Durable responses observed in NHL patients, with 5 patients showing continued response at 6 months and 3 patients at 12 months.
• MT-601's multi-antigen targeting approach (6 tumor antigens) is designed to reduce the possibility of tumor escape.
• The therapy is non-genetically modified, potentially offering an improved safety profile and easier/less expensive manufacturing compared to engineered T cell approaches.
• The study is advancing to the dose expansion phase at the maximum dose (400x10^6 cells) for DLBCL patients, indicating confidence in the preliminary results.
• Significant non-dilutive funding of over $30 million has been secured from NIH, FDA, and CPRIT.
• An optimized manufacturing process for MT-601 has resulted in a 4x increased potency compared to previous studies.

Negatives

• Hodgkin Lymphoma patients showed a lower complete response rate (11%) compared to NHL (50%), despite a high overall response rate.
• The current cash runway is limited, expected to finance operations only into Q2 2026 without additional grant funding, indicating potential future capital needs.
• The reported data is from an early-stage Phase 1 study, and larger, later-stage trials are required to confirm efficacy and safety definitively.
• The number of patients assessed in each subgroup (12 NHL, 9 HL) is relatively small, which may limit the generalizability of the findings.

Risks

• The effectiveness of the company's programs or the possible range of application, potential curative effects, and safety in the treatment of diseases may not meet expectations.
• The timing, conduct, interim results announcements, and outcomes of clinical trials for product candidates, including MT-601, may differ from current projections.
• Forward-looking statements are inherently subject to risks, uncertainties, and other factors that could cause actual results to differ materially from those stated.
• The company's financial stability and cash runway are subject to risks, including the need for additional funding beyond Q2 2026 if further non-dilutive grants are not secured.
• Risks are further detailed in the company's most recent Forms 10-K, 10-Q, and other SEC filings.

Future Outlook

The company expects to advance the APOLLO study to the dose expansion phase, investigating MT-601 at the maximum dose of 400x10^6 cells in patients with relapsed DLBCL, with the aim of further improving clinical efficacy and durability. A further data update is anticipated in the first half of 2026. Management believes MT-601 has the potential to address a critical unmet need for patients who have exhausted multiple lines of treatment, including CAR-T cell therapy, given the high rate of disease progression in CAR-T patients. The post-CD19 CAR-T market is projected to be a multi-billion dollar opportunity. The company also continues efforts to secure non-dilutive funding and plans to expand its cellular inventory for MT-401 Off-the-Shelf (OTS) while advancing other programs like MT-401-OTS in AML/MDS and MT-601 in pancreatic cancer.

Management Comments

• Juan Vera, M.D., President and CEO: "We are very excited and encouraged by the progress of the study. The safety and preliminary efficacy data from our Phase 1 APOLLO study underscore the potential of MT-601 in heavily pre-treated patients with lymphoma, who have relapsed after multiple lines of therapy, including CAR-T cells and bispecific antibodies."
• Juan Vera, M.D., President and CEO: "We believe that MT-601 could address this critical unmet need and offer new hope to patients who have exhausted multiple lines of treatment, including CAR-T cell therapy."
• Juan Vera, M.D., President and CEO: "We look forward to advancing the study to the dose expansion phase, where we will investigate MT-601 at the maximum dose of 400x10^6 cells in patients with relapsed DLBCL to potentially build upon these promising results."
• Juan Vera, M.D., President and CEO: "The encouraging efficacy in patients with NHL was achieved at doses ranging from 100x10^6-200x10^6 cells. We believe that investigating MT-601 at the maximum dose of 400x10^6 cells in the dose expansion cohort could have the potential to further improve the clinical efficacy and durability we are currently observing in patients with NHL."
• Juan Vera, M.D., President and CEO: "It is particularly encouraging that even at the highest dose level no DLTs were reported in the dose escalation phase. We will continue to closely monitor the safety and efficacy of MT-601 in treated patients and anticipate to provide another data update in the first half of 2026."

Industry Context

CAR-T cells have become a standard of care in relapsed/refractory Non-Hodgkin Lymphoma, generating global revenues of $3.1 billion in 2024. However, a significant unmet need exists as 40-60% of CAR-T patients experience disease progression within the first year. MT-601 is positioned to address this critical gap by targeting patients who have relapsed after or are ineligible for anti-CD19 CAR-T cell therapy. The multi-antigen targeting and non-genetically engineered nature of MT-601 differentiate it from existing single-antigen CAR-Ts and bispecific antibodies, which often face challenges with narrow recognition, short-term durability, and increased toxicity. The company projects the post-CD19 CAR-T market to be a multi-billion dollar opportunity, indicating a substantial market for MT-601 if successful.

Comparison to Industry Standards

• MT-601 targets patients who have relapsed after or are ineligible for anti-CD19 CAR-T cell therapy, addressing a significant unmet need where 40-60% of CAR-T patients experience disease progression within the first year.
• Unlike genetically engineered CAR-T cells, MT-601 is a non-genetically modified T-cell therapy, which the company believes offers an improved safety profile (e.g., no ICANS, minimal CRS) and potentially easier/less expensive manufacturing.
• MT-601's multi-antigen recognition (targeting 6 tumor antigens) aims to reduce tumor escape, a limitation often seen with single-antigen targeting approaches used by many CAR-T and T-cell engaging antibody therapies (TCEs).
• Compared to previous MAR-T cell products from the Baylor study (TACTAL, NCT01333046), MT-601 targets 6 antigens versus 5, uses higher cell doses (200x10^6-400x10^6 vs. 10x10^6-40x10^6), and demonstrates 4x increased potency (1,200 SFU/2x10^5 cells vs. 77 SFU/2x10^5 cells), aiming for superior efficacy while maintaining the favorable safety profile.
• The observed durable responses in NHL patients (up to 24 months, with 3 patients showing 12 months durability) compare favorably to the 'unclear durability of response' noted for some bispecific antibodies in the current treatment landscape for CAR-relapsed DLBCL.

Stakeholder Impact

• Shareholders: Positive clinical data could increase investor confidence and potentially share price, but the limited cash runway suggests a future need for capital, which could lead to dilution.
• Patients: Offers new hope and a potentially safer, effective treatment option for heavily pre-treated lymphoma patients who have relapsed after or are ineligible for existing therapies like CAR-T.
• Employees: Positive clinical progress can boost morale and job security, supporting ongoing research and development efforts.
• Regulatory Authorities: Favorable Phase 1 data supports continued clinical development and potential future regulatory approvals.
• Partners/Collaborators: Continued success could attract new partnerships or strengthen existing ones (e.g., Baylor College of Medicine, NCI).

Next Steps

• Advance the APOLLO study to the dose expansion phase, investigating MT-601 at the maximum dose of 400x10^6 cells in patients with relapsed DLBCL.
• Continue to closely monitor the safety and efficacy of MT-601 in treated patients.
• Provide another data update in the first half of 2026.
• Host a live webcast on August 26, 2025, to discuss clinical results and provide a corporate update.
• Continue ongoing efforts to obtain non-dilutive funding.
• Expand cellular inventory for MT-401 Off-the-Shelf (OTS).
• Further develop MT-401-OTS for Acute Myeloid Leukemia (AML) or Myelodysplastic Syndrome (MDS) and MT-601 for pancreatic cancer.

Key Dates

Recommendation

While the Phase 1 APOLLO study results for MT-601 are highly encouraging, demonstrating strong efficacy and a favorable safety profile in a challenging patient population, the early stage of the trial and the limited cash runway into Q2 2026 warrant a 'hold' recommendation. The company has promising technology and non-dilutive funding, but the path to market is long, and future capital raises are likely, which could lead to dilution. Investors should monitor the progress of the dose expansion phase and future financing activities closely.

Keywords

Lymphoma, MT-601, CAR-T, Immuno-oncology, T-cell therapy, Non-Hodgkin Lymphoma, Hodgkin Lymphoma, DLBCL, Clinical trial, Phase 1, Oncology, Cell therapy, Cancer, Relapsed lymphoma, Multi-Antigen Recognizing T cell, MAR-T