Hemogenyx Pharmaceuticals PLC Announces First Patient Treated in Second Adult Dose Cohort

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First Patient Treated in Second Adult Dose Cohort of HG-CT-1 CAR-T Phase I Trial

Dose escalation under way in relapsed or refractory acute myeloid leukemia

LONDON, UK / ACCESS Newswire / November 12, 2026 / Hemogenyx Pharmaceuticals plc (LSE:HEMO), the clinical-stage biopharmaceutical group, is pleased to announce that the first patient in the second adult dose cohort has been treated in the Company’s ongoing Phase I clinical trial of HG-CT-1, its proprietary Chimeric Antigen Receptor T-cell (“CAR-T”) therapy for relapsed or refractory acute myeloid leukemia (“R/R AML”).

The patient received HG-CT-1 at the second dose level: twice the dose administered to the three patients in the first adult cohort. Escalation follows the recommendation of the independent Data Safety Monitoring Board (“DSMB”), which reviewed the safety data from the first cohort, in which no dose-limiting toxicities were observed.

The interval between completion of the first cohort and the start of the second reflects two factors. First, the Company transferred manufacturing of HG-CT-1 to Made Scientific, a contract development and manufacturing organization, completion of which was announced in March 2026. Second, five patients who consented to participate in the second cohort could not be treated because of rapid disease progression, which did not allow manufacture of their HG-CT-1 CAR-T cells to be completed before they were taken off the study. In two of these cases, the cells obtained from the patient were of very poor quality, itself a reflection of rapidly progressing disease. Rapid progression of this kind is characteristic of R/R AML and underlines the need for new treatments.

The patient’s dose was manufactured by Made Scientific and is the first HG-CT-1 product manufactured by Made Scientific to be administered in the trial.

The patient will now be monitored for safety in accordance with the trial protocol, and the Company continues to recruit further patients to the cohort. Recruitment to the pediatric arm of the trial, which opens at the initial adult dose level, is also under way.

The Phase I trial is a dose-escalation study designed to assess the safety of HG-CT-1 and to collect data on key secondary endpoints, including anti-leukemic activity, overall survival, progression-free survival and duration of response. As previously reported, CAR-T cell expansion and persistence were observed in all three patients treated at the first dose level, and reductions in leukemic blast burden were recorded in peripheral blood and/or bone marrow, with no immune effector cell-associated neurotoxicity syndrome and no dose-limiting toxicities. These findings are preliminary, given the small number of patients treated to date.

Dr. Vladislav Sandler, CEO & Co-Founder of Hemogenyx Pharmaceuticals, commented:

“Treating the first patient at the higher dose marks the start of dose escalation in our Phase I trial of HG-CT-1. The first cohort gave us an encouraging safety profile at the lowest dose, together with early signs of biological activity; the second cohort will begin to show how safety and anti-leukemic activity respond to dose. We are grateful to the patient and their family, and to our clinical investigators, and we look forward to updating shareholders as the cohort progresses.”

Market Abuse Regulation (MAR) Disclosure

Certain information contained in this announcement would have been deemed inside information for the purposes of Article 7 of Regulation No 596/2014 (as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018) until the release of this announcement. The person responsible for arranging for the release of this announcement on behalf of Hemogenyx Pharmaceuticals plc is Dr Vladislav Sandler, Chief Executive Officer & Co-Founder.

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About Hemogenyx Pharmaceuticals plc

Hemogenyx Pharmaceuticals is a publicly traded company (LSE:HEMO) headquartered in London, with its US operating subsidiaries, Hemogenyx Pharmaceuticals LLC and Immugenyx LLC, located in New York City at its state-of-the-art research facility.

The Company is a clinical stage biopharmaceutical group developing new medicines and treatments to treat blood and autoimmune diseases. Hemogenyx Pharmaceuticals is developing several distinct and complementary product candidates, as well as platform technologies that it uses as engines for novel product development.

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SOURCE: Hemogenyx Pharmaceuticals PLC

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