On May 11, 2026 CERo Therapeutics Holdings, Inc. (OTCQB: CERO) ("CERo" or the "Company"), an innovative cellular immunotherapy company advancing next-generation engineered T cell therapeutics that employ phagocytic mechanisms, reported that it has completed dosing and the 28-day dose-limiting toxicity ("DLT") assessment period for all three patients in the second cohort of its Phase 1 CERTAIN-T clinical trial of CER-1236 in hematologic malignancies.

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In the second cohort, patients received CER-1236 at a total dose of 4 × 10⁶ cells/kg, administered as a split dose on Day 0 and Day 2. No DLTs were observed through the DLT assessment window, supporting continued dose escalation in accordance with the clinical protocol. The observed safety profile remains consistent with clinical data presented at the Tandem Meetings in February, which reported no cytokine release syndrome ("CRS"), immune effector cell-associated neurotoxicity syndrome ("ICANS"), DLTs, or treatment-related severe adverse events during the DLT assessment window.

CERo is now escalating to the planned 1 × 10⁷ cells/kg split-dose cohort and is screening patients for enrollment. This next cohort is expected to include patients with myelodysplastic syndrome ("MDS") and myelofibrosis ("MF"), reflecting the Company’s strategy to evaluate CER-1236 in myeloid disease settings characterized by inflammatory bone marrow microenvironments and impaired hematopoiesis.

The Company has now treated six patients in its Phase 1 trial. In the most recent cohort of three patients, CER-1236 was administered at an increased dose level, with no dose-limiting toxicities observed during the DLT assessment period. As previously reported, CERo has also observed expansion of infused CER-1236 cells following administration, supporting continued evaluation of CER-1236’s pharmacokinetic and pharmacodynamic profile as the study advances through dose escalation.

Robert Sikorski, M.D., Ph.D., CERo Chief Medical Officer, stated, "We are encouraged by the continued progress of the CERTAIN-T study, including completion of the second dose cohort and advancement to the next planned dose level. As we proceed in accordance with the clinical protocol, our priority remains the careful evaluation of the safety, tolerability, pharmacokinetic profile, and preliminary clinical activity of CER-1236. The planned inclusion of patients with MDS and MF reflects our interest in exploring CER-1236 across additional hematologic malignancies with significant unmet need and further assessing the potential of its differentiated phagocytic CAR-T mechanism."

The first-in-human, multicenter, open-label Phase 1/1b study is designed to evaluate the safety and preliminary efficacy of CER-1236. The trial was initially focused on AML patients, including those with relapsed/refractory disease, measurable residual disease, or newly diagnosed TP53-mutated AML, and has since expanded to include transfusion-dependent MDS ("TD-MDS"), high-risk MDS ("HR-MDS"), and post-JAK inhibitor MF. Primary endpoints include safety and tolerability, while secondary endpoints include pharmacokinetics and measures of clinical response, including overall response rate (ORR), complete response (CR), composite complete response (cCR), and measurable residual disease (MRD).

CERo Chief Executive Officer Chris Ehrlich added, "The advancement of CER-1236 through dose escalation continues at a steady pace and we remain focused on evaluating its potential across hematologic malignancies with significant unmet need. We look forward to providing additional clinical updates as the study progresses."

(Press release, Cero Therapeutics, MAY 11, 2026, View Source [SID1234665481])