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6 October 2025

Hemogenyx Pharmaceuticals plc
("Hemogenyx Pharmaceuticals" or the "Company")

MD Anderson Clearance to Initiate Pediatric Enrolment in HG-CT-1 Clinical Trial

Hemogenyx Pharmaceuticals plc (LSE: HEMO) is pleased to announce that the Institutional Review Board ("IRB") at MD Anderson Cancer Center ("MD Anderson") has approved an amendment to the clinical protocol of the Company's ongoing Phase I trial of HG-CT-1, its proprietary CAR-T cell therapy for the treatment of relapsed or refractory acute myeloid leukemia ("R/R AML").

The approved amendment expands the eligibility criteria for the trial to include children and adolescents with R/R AML, allowing the Company to begin enrolling pediatric patients into the study. This important step builds on the safety and early efficacy signals already observed in adult participants and significantly broadens the potential patient population who may benefit from HG-CT-1.

Dr. Vladislav Sandler, CEO & Co-Founder of Hemogenyx Pharmaceuticals, commented:
"Securing IRB clearance to proceed with pediatric enrolment in our HG-CT-1 clinical trial is a major milestone. It marks the transition of HG-CT-1 into the pediatric setting, where treatment options remain limited, and demonstrates the continued momentum of our development program. This expansion not only increases the potential reach and impact of HG-CT-1 but also underscores the value of the Company's strong intellectual property portfolio, which underpins our pipeline and supports long-term growth."

The Company will provide further updates as both adult and pediatric patient enrolment progresses.

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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.

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.