PeproMene Bio announced that interim data from its Phase 1 trials of PMB-CT01, a first-in-class BAFFR-CAR T cell therapy, will be presented at the 2025 American Society of Hematology (ASH) Annual Meeting. The therapy has demonstrated promising safety and efficacy results in heavily pretreated patients with relapsed and refractory B-cell malignancies, including those who failed prior CD19-directed therapy.
Exceptional Safety Profile in B-Cell Lymphoma
In the relapsed/refractory B-cell Non-Hodgkin Lymphoma (r/r B-NHL) cohort, PMB-CT01 demonstrated an exceptionally favorable tolerability profile. No patients experienced Grade ≥1 Cytokine Release Syndrome (CRS) or Grade ≥1 Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS), representing a significant safety advantage over existing CAR T therapies.
All seven patients in the initial B-NHL cohort achieved complete response (CR) at 1-3 months post-infusion, including patients previously treated with CD19 CAR T therapy and those with CD19-negative disease. Remissions have remained ongoing for up to 32+ months, with a median duration of 17 months at data cutoff.
Promising Activity in Acute Lymphoblastic Leukemia
In the relapsed/refractory B-cell Acute Lymphoblastic Leukemia (r/r B-ALL) study, four of six enrolled patients achieved undetectable Minimal Residual Disease (MRD-) complete remission. Notably, three of the four responders were CD19-negative at enrollment, and all three successfully transitioned to allogeneic hematopoietic cell transplant with curative intent.
The safety profile in B-ALL patients was similarly favorable, with no dose-limiting toxicities observed. Only one patient experienced Grade 2 CRS, with no Grade 3 CRS reported across the cohort.
Targeting CD19 Resistance
PMB-CT01 targets BAFF-R (B-cell Activating Factor Receptor), which is expressed almost exclusively on B cells and is essential for B-cell survival. This targeting strategy is designed to overcome CD19 antigen escape, a common mechanism of resistance to current CAR T therapies.
"The consistent and durable activity seen across both B-ALL and B-NHL, particularly in patients who have exhausted CD19 CAR T options or present with CD19-negative disease, strongly supports BAFF-R as a highly effective and safe alternative target," said Hazel Cheng, Ph.D., COO of PeproMene Bio. "These data highlight PMB-CT01's potential to address critical unmet needs in high-risk relapsed disease."
ASH 2025 Presentations
The company will present two abstracts at the ASH Annual Meeting. Elizabeth Budde, M.D., Ph.D., will present data on BAFFR-CAR T cells in B-cell lymphomas on December 6, while Ibrahim Aldoss, M.D., will present the B-ALL data on December 8.
The interim results are from two Phase 1 dose-escalation studies (NCT04690595, NCT05370430) evaluating PMB-CT01 in patients with relapsed and refractory B-cell malignancies. PeproMene Bio, a clinical-stage biotechnology company based in Irvine, California, is developing the therapy as a potential treatment option for patients with limited therapeutic alternatives.
