In a first-in-human study, researchers at The University of Texas MD Anderson Cancer Center observed strong responses and early signs of antitumor activity in patients with difficult-to-treat non-Hodgkin lymphomas who received the novel cell therapy RB-1355. The therapy was effective for those who have relapsed after multiple treatments or no longer responded to standard-of-care options, such as CAR T cell therapy.
Findings from the study were presented by Paolo Strati, M.D., associate professor of Lymphoma, at the 2026 Tandem Meetings of the American Society for Transplantation and Cellular Therapy (ASTCT) and Center for International Blood and Marrow Transplant Research (CIBMTR).
“These early results are very encouraging and shine a light on how we can harness the power of the body’s immune system in a new way when treating patients,” Strati said. “This approach has the potential to open a new pathway for challenging lymphoma cases and patients who do not have effective treatments available to them.”
How does RB-1355 work?
RB-1355 is a new cell therapy made from a patient’s own immune cells. Using a proprietary ex-vivo manufacturing process, immune cells called macrophages are hyperactivated and programmed to reshape the tumor microenvironment toward a proinflammatory and immune supportive state. This treatment sparks the broad activation of an anti-lymphoma immune cascade that includes neoantigen-specific T cell and B cells.
RB-1355 can be manufactured relatively quickly, generally being ready for treatment in about a week. Patients receive the treatment through a series of injections made directly into a patient’s lesions without requiring lymphodepleting chemotherapy.
The study included patients with various B and T cell lymphomas, as RB-1355 does not require a patient’s cancer to express actionable mutations, making it a potential treatment across all lymphoma indications.
The trial’s key findings
Thirteen patients with advanced B-cell or T-cell lymphomas were treated as part of the trial. Two individuals with diffuse large B-cell lymphoma who had relapsed or had not responded to CAR T cell therapy achieved complete remissions. One patient remained disease-free more than 100 days after treatment. Partial responses were observed in patients with peripheral T-cell lymphoma and mycosis fungoides. These patients had no standard treatment options left.
There were no clinically meaningful side effects, and no dose-limiting toxicities were observed. Only three cases of low-grade toxicity were reported.
These early findings suggest that RB-1355 offers a potentially powerful new approach for patients with relapsed or refractory lymphomas, which is significant as these patients often have few treatment options remaining for them. Higher doses or repeated treatment cycles may provide a more durable response, according to Strati. Further investigations are currently underway.
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