Hemogenyx Pharmaceuticals plc

(“Hemogenyx” or the “Company”)

CDX Antibody is Effective against AML in vivo

Hemogenyx Pharmaceuticals plc (LSE: HEMO) announces the first data results from in vivo testing of its CDX bi-specific antibody (“CDX antibody”) product candidate for the treatment of Acute Myeloid Leukemia (“AML”), a form of blood cancer. This follows the successful in vitro testing of the CDX antibody for the treatment of Acute Lymphoblastic Leukemia (“ALL”) announced on 30 May 2019.

The first data results demonstrate that the CDX antibody is capable of eliminating a subset of AML cells in vivo. The CDX antibody was shown to target AML cells that overexpress the protein FLT3. The CDX antibody binds to the FLT3 protein that is located on the surface of unwanted (target) cells, binds to the CD3 protein on the surface of T-cells, and ultimately redirects T-cells to kill the target cells. The Company has verified the efficacy of CDX against AML in vivo, using its proprietary advanced hematopoietic chimeric (“AHC”) mice (humanized mice).

Background on Acute Myeloid Leukemia

AML affected about one million people globally in 2015 and resulted in 147,000 deaths. AML accounts for roughly 1.8% of cancer deaths in the United States with more than 20,000 new cases diagnosed in the US and 18,000 cases in Europe every year.

Despite numerous advances in understanding the biology and pathogenesis of AML, treatment remains unsatisfactory. Relapsed or refractory (R/R) AML is nearly universally fatal. The only curative treatment is allogeneic hematopoietic stem cell transplantation (HSCT) with success rates less than 30% in the patients with chemo-sensitive disease. Unfortunately, most patients lack sensitivity to currently available therapies and therefore do not consider transplant or have extremely poor outcomes following allogeneic HSCT. The Directors believe that the Company’s CDX antibody could replace traditional methods of treatment of relapsed/refractory AML.

It is estimated that the value of the global therapeutic market for AML was about $700M in 2018 and expected to grow to more than $1.5B by 2024.

Vladislav Sandler, Chief Executive Officer, commented, “We are encouraged by this new data which demonstrates our continuing progress in the development and potential uses of our CDX antibody. We previously demonstrated that the CDX antibody may be effective in treating AML in vitro. Our new data demonstrates CDX antibody efficacy when tested in vivo in our own proprietary AHC model. This antibody should, if successful, provide a new and potentially effective treatment for a form of blood cancer for which survival rates are currently poor.”

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.

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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 in New York City at its state-of-the-art research facility 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.

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