Hemogenyx Pharmaceuticals plc

(“Hemogenyx” or the “Company”)

Development of ApbHC, a Novel Type of Humanized Mouse

Hemogenyx Pharmaceuticals plc (LSE: HEMO) announces that its wholly owned subsidiary Immugenyx, LLC (“Immugenyx”) has developed an Advanced peripheral blood Hematopoietic Chimera (“ApbHC”), a novel type of humanized mouse that presents several advantages over other mouse models. Immugenyx was established by the Company to develop and commercialise the Company’s Advanced Hematopoietic Chimeras (AHC) or humanized mice and the new ApbHC represents a significant further development in that direction.

As with AHC, the Company believes that the ApbHC will be of considerable interest to other drug developers and initial interest shown is promising.

The ApbHC was initially developed as a research and development tool for the investigation of mature blood cell populations such as human T-cells, B-cells and antibody-producing plasma cells. The major advantage of the ApbHC compared to other humanized mouse models known to the Directors is the absence of Graft versus Host Disease, a disease that complicates and often renders impossible the efficient use of peripheral blood mononuclear cells in transplanted mice. Hemogenyx has demonstrated that the ApbHC can potentially be used for testing multi-specific antibodies, including its own bi-specific CDX antibody for the elimination of acute myeloid leukemia (AML) and the conditioning of patients for bone marrow transplantation. ApbHC may also be used for the development and testing of new cell therapies involving immune cell reprogramming, such as CAR-T. Immugenyx has further demonstrated that the ApbHC can potentially be used for the modeling of autoimmune diseases, such as Systemic Lupus Erythematosus (aka Lupus), with a goal of developing fundamentally new treatments for those diseases. The Directors also believe that the ApbHC could potentially be used as a tool for the rapid development and/or isolation of human antibodies against unknown human-specific pathogens (biodefense applications).

Vladislav Sandler, Chief Executive Officer, commented, “We are excited by the potential of the ApbHC, a new generation of our humanized mice. The ApbHC has allowed us to rapidly obtain in vivo data on the efficacy of our CDX antibodies against AML. We are actively developing and expanding the potential use of the ApbHC for disease modeling, the development of new therapeutics, and biodefense applications. Our ApbHC has also generated significant interest from third parties who also see its potential for disease modeling and drug development.”

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 (EU) No 596/2014 until the release of this announcement.

Enquiries:

About Hemogenyx Pharmaceuticals plc

Hemogenyx Pharmaceuticals plc (“Hemogenyx”) is a publicly traded company (LSE: HEMO) headquartered in London, with its wholly-owned US operating subsidiaries, Hemogenyx LLC and Immugenyx LLC, located at its state-of-the-art research facility in New York City and a wholly-owned Belgian operating subsidiary, Hemogenyx-Cell SPRL, located in Liège.

Hemogenyx is a pre-clinical stage biopharmaceutical group developing new medicines and treatments to bring the curative power of bone marrow transplantation to a greater number of patients suffering from otherwise incurable life-threatening diseases. Hemogenyx is developing two distinct and complementary products, as well as a platform technology that it uses as an engine for novel product development.

For more than 50 years, bone marrow transplantation has been used to save the lives of patients suffering from blood diseases. The risks of toxicity and death that are associated with bone marrow transplantation, however, have meant that the procedure is restricted to use only as a last resort. Hemogenyx’s technology has the potential to enable many more patients suffering from devastating blood diseases such as leukemia and lymphoma, as well as severe autoimmune diseases such as multiple sclerosis, aplastic anemia and systemic lupus erythematosus (Lupus), to benefit from bone marrow transplantation.

MSCFJMJTMBJTBJL