New CAR-T Therapy Shows Durable Remissions in Advanced Lymphoma After Other Treatments Fail

IRVINE, CA – May 28, 2026 – By Deborah Cooper

For patients with aggressive B-cell non-Hodgkin lymphoma, the journey through treatment can be a grueling series of hopes and setbacks. While CAR T-cell therapy, a revolutionary approach that engineers a patient's own immune cells to fight cancer, has been a lifeline for many, a significant portion of patients eventually see their cancer return, often more resistant than before. For this group, which faces a grim prognosis and dwindling options, a new investigational therapy is showing profound promise.

Irvine-based PeproMene Bio, Inc. has announced striking results from a Phase 1 trial of its next-generation CAR T-cell therapy, PMB-CT01. The data, selected for a prestigious oral presentation at the 2026 European Hematology Association (EHA) Congress, reveal that the therapy can induce deep, lasting remissions even in patients who have already failed a prior CAR T-cell treatment. The early findings suggest a potential paradigm shift in how oncologists may one day manage these difficult-to-treat cancers.

A Second Chance at Remission

The most compelling data comes from the initial dose-escalation phase of the trial, which involved nine patients with relapsed or refractory B-cell lymphomas. These were heavily pretreated individuals for whom standard therapies, including the current generation of CD19-targeted CAR T-cells, had stopped working. In this high-risk population, PMB-CT01 achieved a 78% complete response rate, meaning seven of the nine patients saw all signs of their cancer disappear.

Even more remarkably, these responses appear to be exceptionally durable. At the time of the data analysis, none of the responding patients had relapsed, with the longest remission now extending beyond three years. All responders also achieved a status known as minimal residual disease (MRD)-negative, a highly sensitive measure indicating that no detectable cancer cells remain in the body. This depth of response is a key predictor of long-term survival.

The trial has since moved into an expansion phase, and the early success continues. The first patient treated in this new cohort—a person with transformed follicular lymphoma, an aggressive subtype, who had also progressed after a CD19 CAR T-cell therapy—achieved a complete response at their very first assessment. This result provides further validation that PMB-CT01 can effectively combat cancers that have learned to evade the industry's frontline cell therapies.

Redefining Safety in Cell Therapy

While the efficacy of CAR T-cell therapy is well-established, its adoption has been tempered by the risk of severe, and sometimes life-threatening, side effects. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are inflammatory conditions that can cause high fevers, organ dysfunction, and neurological problems, often requiring intensive care unit management. Approved CAR T-cell therapies like Kymriah and Yescarta report high rates of CRS, with a significant percentage of patients experiencing severe grade 3 or 4 events.

In stark contrast, PMB-CT01 has demonstrated an exceptionally favorable safety profile. Among the nine patients in the initial cohort, there were no dose-limiting toxicities, and crucially, no patient experienced CRS or ICANS beyond grade 1—the mildest form. This remarkable safety data sets it apart from existing treatments and could have transformative implications. A therapy with such a low risk of severe toxicity could potentially be administered in outpatient clinics or community oncology centers, dramatically increasing patient access and reducing the burden on specialized academic hospitals.

"When cancer progresses following CD19 CAR T therapy, patients face a significant unmet medical need, with very limited treatment options remaining," said Dr. Larry W. Kwak, scientific founder of PeproMene Bio, in the company's announcement. He noted that the therapy's safety profile "may support future use in outpatient community oncology settings."

The Science of a Smarter Target: BAFF-R

The innovation behind PMB-CT01 lies in its target. Most current CAR T-cell therapies are designed to recognize a protein called CD19, which is found on the surface of B-cells. However, a primary reason for treatment failure is "antigen escape," where cancer cells stop expressing CD19, effectively becoming invisible to the CAR T-cells.

PMB-CT01 targets a different protein: the B-cell activating factor receptor, or BAFF-R. This receptor is not just present on B-cells; it is essential for their survival. Because cancer cells rely on BAFF-R to live and proliferate, they are far less likely to stop expressing it as a way to evade therapy. This makes BAFF-R a more robust and durable target, potentially preventing the relapses seen with CD19-directed treatments.

"These durable CRs clinically validate BAFF-R as a novel target," stated Dr. Kwak. This validation opens a new front in the war on B-cell cancers, offering a powerful strategy to overcome the primary mechanism of resistance to current cell therapies.

PeproMene's Path in a Crowded Field

As a clinical-stage biotechnology company, PeproMene Bio is navigating a highly competitive landscape. The field of post-CAR-T relapse is rapidly evolving, with other approaches like bispecific T-cell engagers (BiTEs) also showing promise. However, the combination of deep, durable responses and an outstanding safety profile gives PMB-CT01 a potentially best-in-class profile.

The company, which has licensed the core technology from the world-renowned City of Hope medical center, is backed by strategic investments, including a recent $11 million commitment from the Institute for Follicular Lymphoma Innovation (IFLI) to specifically advance the therapy in that subtype. With its Phase 1 trial now expanding to enroll more patients with mantle cell lymphoma, large B-cell lymphoma, and follicular lymphoma, PeproMene is systematically building the evidence needed for a therapy that could one day offer a new standard of care. The promising data also hints at broader applications, with Dr. Kwak suggesting future exploration in refractory autoimmune diseases, where targeting B-cells is also a key therapeutic strategy.