Marker Therapeutics Updates on MT-601 for Lymphoma Patients

Marker Therapeutics, Inc., a clinical-stage immuno-oncology company listed on Nasdaq as MRKR, has provided an update on its Phase 1 APOLLO study. This study is focused on evaluating the safety and efficacy of MT-601, a multi-antigen recognizing T cell product, in patients with lymphoma who have relapsed following anti-CD19 chimeric antigen receptor (CAR) T cell therapy or for whom such therapy is not viable. As of the data cutoff date of September 10, clinical data is available for nine out of ten patients treated in this study, which is being conducted across five clinical sites in the United States.

MT-601, previously known as multi-tumor associated antigen-specific T cells, is designed to address an unmet medical need in the treatment landscape, particularly for patients who relapse after CD19-targeting CAR-T cell therapies. These therapies have shown promise but also come with significant challenges, including a relapse rate of 40-60% within the first year and adverse effects like cytokine release syndrome (CRS) and immune-effector cell associated neurotoxicity syndrome (ICANS).

The APOLLO study is exploring a non-genetically modified approach, where MT-601 is used to harness the body's natural tumor-specific T cells. These T cells can identify and attack a wide array of tumor antigens, thus minimizing the risk of tumor escape and potential mutagenesis, a concern with genetically engineered therapies. This method not only enhances safety but also reduces manufacturing complexities and costs.

Initial results from the study are promising. Among the nine patients assessed, 78% showed objective responses at the first evaluation, with 44.4% achieving a complete response. Importantly, the treatment was well tolerated, with no cases of ICANS reported. Only one patient experienced a mild case of CRS, and no dose-limiting toxicities were observed. These outcomes suggest that MT-601 could potentially offer a safer alternative to existing therapies.

The study is currently in the dose-escalation phase, with plans to enroll up to 30 participants across nine clinical sites in the United States. Long-term follow-up data is available for three patients, ranging from six to twelve months, and ongoing monitoring seeks to evaluate the durability of responses.

Dr. Monic Stuart, the Chief Medical Officer at Marker Therapeutics, expressed optimism about the study's findings. The ability to achieve objective responses in heavily pre-treated patients, many of whom have undergone multiple lines of therapy including CAR-T cells, highlights the potential impact of MT-601. The company continues to recruit more participants to gather comprehensive data, which will inform the future development strategy for MT-601.

Dr. Juan Vera, President and CEO of Marker Therapeutics, emphasized the significance of these developments for patients who currently have no approved standard of care post-CD19 CAR-T relapse. The promising safety and efficacy profile of MT-601 could fill this gap, providing new hope for a large and growing patient population.

Marker Therapeutics stands out in the field of T cell-based immunotherapies due to its innovative MAR-T cell platform, which selectively expands T cells capable of recognizing numerous tumor-specific antigens. This approach not only targets a broader spectrum of tumor antigens but also offers a more favorable safety profile compared to genetically modified T cell therapies.

As the APOLLO study progresses, Marker Therapeutics continues to focus on operational excellence and the efficient allocation of financial resources to advance its T cell-based therapies. With support from state and federal agencies, the company remains committed to delivering novel cancer treatments and improving patient outcomes.