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Highlights

  • 66% objective response rate in Non-Hodgkin Lymphoma patients, 50% complete responses.
  • Durable responses ranged 3–24 months; five patients remain responder ≥6 months.
  • Safety profile acceptable: no dose-limiting toxicities or serious adverse events.

Marker Therapeutics reported encouraging early efficacy and tolerability data from its Phase 1 APOLLO study of MT-601, a Multi-Antigen Recognizing T cell product, in relapsed lymphoma. The trial enrolled 24 B-cell lymphoma patients across seven U.S. clinical sites with dose levels spanning 100×10^6 to 400×10^6 cells. In the pooled Non-Hodgkin Lymphoma (NHL) cohort, investigators observed a 66% objective response rate (ORR), with half of evaluable patients achieving complete response (CR).

The company also disclosed response signals in Hodgkin Lymphoma, reporting a 78% ORR in that subgroup; however, only one complete response (11%) was recorded among Hodgkin patients. Durable activity was documented, with responses lasting between three and 24 months and five patients maintaining responses for six months or longer. Importantly for a first-in-human study, the regimen cleared the maximum planned dose of 400×10^6 cells and the programme is advancing into a dose-expansion phase targeting diffuse large B-cell lymphoma (DLBCL) patients who have relapsed after, or are ineligible for, CAR-T therapy.

Safety data from APOLLO were broadly favourable. There were no dose-limiting toxicities or serious adverse events attributed to MT-601, and only two instances of Grade 1 cytokine release syndrome (CRS) were reported. These signals suggest a tolerability profile that may support further development, though the regulatory and clinical paths ahead will require larger, controlled datasets.

Caveats are significant. Phase 1 trials are designed primarily to assess safety and dose, and the small cohort sizes here limit the precision and generalisability of the reported response rates. The imbalance between ORR and complete responses in the Hodgkin subgroup highlights variability that may reflect small sample effects or heterogeneity in patient characteristics. Follow-up remains limited for many patients, and longer observation will be necessary to understand durability and late toxicities.