2 May 2025

Hemogenyx Pharmaceuticals plc

("Hemogenyx Pharmaceuticals" or the "Company")

Second Patient Treated with HG-CT-1 CAR-T Therapy

Hemogenyx Pharmaceuticals plc (LSE: HEMO) is pleased to announce that the second patient has been successfully treated as part of the Company's ongoing Phase I clinical trial of HG-CT-1, its proprietary CAR-T cell therapy for the treatment of relapsed or refractory acute myeloid leukemia ("R/R AML") in adults.

This milestone follows the successful first-in-human treatment with HG-CT-1, which demonstrated a favorable initial safety profile with no adverse effects observed, and the subsequent recruitment of the second patient. Together, these milestones mark steady progress in the clinical development of HG-CT-1 and reinforce the Company's commitment to advancing treatment options for patients with limited therapeutic alternatives.

The Phase I trial is a dose-escalation study designed to assess the safety profile 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.

The Company believes that continued clinical execution will not only advance a potentially transformative treatment for adult patients with limited therapeutic options but also generate long-term value for shareholders by establishing HG-CT-1 as a platform-defining asset in the field of hematologic malignancies. While the current trial is focused on adult patients, successful initial outcomes would pave the way for a pediatric trial - an area of significant unmet medical need in AML, where few effective treatment options exist for children.

Further updates on the clinical trial will be provided in due course.

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

"The treatment of a second patient with HG-CT-1 marks another critical step in the development of our CAR-T therapy for relapsed or refractory AML. The ability to move forward with dosing reflects the capabilities of our scientific and manufacturing teams and further validates our platform. We remain deeply focused on executing the clinical program with rigor and care, and on our mission to bring potentially life-saving treatments to patients in need."

Market Abuse Regulation (MAR) Disclosure

Certain information contained in this announcement would have been 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.