Collaboration and Company Update

29 July 2026

Hemogenyx Pharmaceuticals plc

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

Collaboration with Vilnius University Hospital Santaros Klinikos on HG-CT-1 Clinical Application and Research

London, UK - Hemogenyx Pharmaceuticals plc (LSE:HEMO) is pleased to announce that it has signed a Letter of Intent ("LOI") with the National Cancer Centre at Vilnius University Hospital Santaros Klinikos ("NCC" or the "Hospital"), one of Lithuania's leading academic medical centers, to establish a scientific and clinical collaboration in FLT3-positive[1] acute myeloid leukemia ("AML") and myelodysplastic syndromes ("MDS").

Highlights

●     The LOI establishes a collaboration to advance the understanding and treatment of FLT3-positive AML and MDS, comprising two complementary workstreams.

●     Workstream 1 - a translational research program characterizing FLT3 expression and biology across AML/MDS genetic subtypes and disease compartments.

●     Workstream 2 - in-hospital (point-of-care) manufacturing and clinical use of Hemogenyx's FLT3-directed CAR-T cell therapy (the "Therapy" or "HG-CT-1") to eligible patients.

●     Patient treatment is intended to be carried out under the hospital exemption rules and other applicable pathways in force in the Republic of Lithuania, consistent with Lithuanian and EU law governing advanced therapy medicinal products ("ATMPs").

●     Hemogenyx retains full ownership of all intellectual property, know-how, data and regulatory rights relating to the Therapy and its FLT3 CAR-T technology.

[1] FLT3 (FMS-like tyrosine kinase 3) is a protein found on the surface of blood-forming cells that helps control how these cells grow and multiply. In many patients with acute myeloid leukemia (AML), FLT3 is present at abnormally high levels or is mutated, which can drive the uncontrolled growth of cancerous cells. This makes FLT3 an important target for new therapies designed to attack leukemia cells while sparing healthy tissue.

Background and Scope of the Collaboration

AML and MDS are aggressive blood cancers with a high unmet medical need, particularly in relapsed or refractory ("R/R") patients. FLT3 is a clinically validated target that is frequently expressed in these diseases. The collaboration is designed to deepen the scientific understanding of FLT3 biology while creating a route to treat patients with Hemogenyx's HG-CT-1 therapy at the point of care.

Workstream 1 - FLT3 Biology in AML/MDS (Research)

The research program will characterize FLT3 expression and biology across AML/MDS genetic subtypes, including patterns of disease evolution over the course of treatment, and will analyze FLT3 expression across disease compartments, including cerebrospinal fluid and myeloid sarcomas, in both de novo and R/R patient samples. This workstream will be led by Andrius Žučenka, MD, PhD, of the Hospital, in collaboration with Hemogenyx.

Workstream 2 - HG-CT-1 Manufacturing and Clinical Use

The parties intend to establish in-hospital (point-of-care) manufacturing of the Therapy at the NCC and to administer it to eligible AML/MDS patients on a compassionate-use basis under the Lithuanian hospital exemption framework. This workstream will be coordinated on Hemogenyx's side by Dr Vladislav Sandler, with the clinical side at the Hospital led by Prof. Dr. Med. Laimonas Griškevičius.

Roles, Intellectual Property and Commercial Principles

Under the LOI, Hemogenyx will provide the scientific information, materials, technology transfer and training required for manufacturing and administration of the Therapy and will contribute scientific leadership to the research program. The Hospital will act as Hemogenyx's local manufacturing, clinical and research partner in Lithuania; provide access to appropriately consented patient samples and clinical data, subject to ethics approvals and data-protection law; establish and operate in-hospital manufacturing; and lead engagement with Lithuanian and, where applicable, European regulatory and bioethics authorities.

Hemogenyx retains all pre-existing intellectual property and all rights in the Therapy and its underlying technology and shall be entitled to revenues generated from the commercialization of the Therapy. The Hospital and Hemogenyx may each receive compensation from or through the Lithuanian Compulsory Health Insurance Fund, the Hospital for its manufacturing, regulatory, clinical and research services, and Hemogenyx for the materials and technology transfer used to produce the Therapy. Any such compensation shall be subject to negotiation in the definitive agreements between the Hospital and Hemogenyx.

The Collaboration may enable Hemogenyx to receive clinical data from the treatment of R/R AML patients in Lithuania in parallel with the Company's ongoing clinical trials in the United States. The Collaboration is separate from, and not connected with, a further collaboration under discussion in Estonia (as disclosed 23 on September 2025), which the Company hopes is nearing finalization. The Company understands that both countries, together with the wider European Union, have significant unmet demand for novel treatments for R/R AML, should testing of the Therapy prove successful in due course. It should be noted, however, that considerable preparatory work will be required before patient treatment can begin.

Management Comment

Dr Vladislav Sandler, Chief Executive Officer and Co-Founder of Hemogenyx Pharmaceuticals, said:

"This Letter of Intent with the National Cancer Centre at Vilnius University Hospital Santaros Klinikos is an important step in bringing our HG-CT-1 CAR-T therapy closer to patients who urgently need new options. By pairing a focused research program on FLT3 biology with point-of-care manufacturing and compassionate-use treatment under Lithuania's hospital exemption framework, we have a pragmatic route to generate clinical experience while retaining full ownership of our technology. It may also open up opportunities to expand the use of our technology for additional indications. We look forward to working with the Hospital's outstanding clinical and scientific teams to advance this collaboration towards definitive agreements."

Update on the Company's Wider Activities

Alongside the collaboration described above, the Company provides the following update on its wider development activities.

HG-CT-1 in adults (R/R AML)

Hemogenyx continues its Phase 1 clinical trial of HG-CT-1 in adult patients with R/R AML. The next adult cohort is scheduled to be treated at the increased (second) dose level of HG-CT-1, and several patients have been identified and screened for eligibility to participate in the study. It is not possible to predict the timing of patient testing but our hospital partners remain committed to the continuation of tests.

HG-CT-1 in pediatric patients

Hemogenyx has initiated a pediatric Phase 1 clinical trial of HG-CT-1. The first pediatric patient has been identified and is undergoing screening for eligibility to participate in the study. As in the case of adult arm of the trials, it is not possible to predict the timing of patient testing but our hospital partners remain committed to the continuation of tests.

Chimeric Bait Receptor (CBR) platform

The Company continues to develop its CBR platform. Results to date are promising; however, development is deliberately measured, as the Company remains focused on its lead product candidate, HG-CT-1, and is choosing to preserve its resources.

CDX bispecific antibody

The Company continues to develop its CDX bispecific antibody for the treatment of R/R AML. As with the CBR platform, development is proceeding at a measured pace while the Company prioritizes HG-CT-1 and preserves its resources.

The Board notes that clinical trials in R/R AML are inherently difficult, principally because of the health status of potential participants. This directly affects patient eligibility and the pace at which the trials can progress. The Company is managing its programs with this in mind and remains focused on advancing HG-CT-1 as its lead priority.

We continue to manage our resources in a highly conservative manner while the patient recruitment process continues.

Enquiries

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.