PRESS RELEASE

Heidelberg Pharma to Present Data from its ADC Technology Platforms at AACR Annual Meeting 2025 

Ladenburg, Germany, 26 March 2025 – Heidelberg Pharma AG (FSE: HPHA), a clinical-stage biotech company developing innovative Antibody Drug Conjugates (ADCs), today announced that it will be presenting its latest ADC research results and advancement for its Exatecan-based ADC technology platform at the American Association of Cancer Research (AACR) Annual Meeting 2025 in Chicago, Illinois, USA, from 25 to 30 April.

In addition to its proprietary Amanitin-based ADC technology, Heidelberg Pharma has developed a diverse ADC toolbox designed to overcome tumor resistance through multiple mechanisms, enabling targeted treatment across various cancer types.

Dr. Sarah-Jane Neuberth will present preclinical findings on HDP-201, Heidelberg Pharma´s novel Exatecan-based, multimeric linker ADC, called ETAC technology, which is being developed for the treatment of colorectal cancer. The findings indicate target-specific potency, strong anti-tumor efficacy, and high tolerability.

Dr. Pablo Ruedas Batuecas will demonstrate the potential of computational modeling for optimizing NAMPT inhibitors (NAMPTi) designed in silico as payloads and as a mode of action (MOA) in ADC technology. This novel technology approach has the potential to overcome the current limitations of cancer therapies by targeting both dividing and non-dividing cancer cells.

Details of the conference and presentations are as follow:

Poster: HDP-201 – a novel multimeric linker exatecan-based ADC targeting Guanylyl cyclase C (GCC) for treatment of gastrointestinal malignancies

The ETAC HDP-201 is directed against the surface protein GCC (guanylyl cyclase C), which is highly overexpressed in gastrointestinal malignancies, including gastric and colorectal cancers.

HDP-201 showed potent anti-tumor efficacy in preclinical models, including complete tumor remission of GCC-expressing CDX models and significant inhibition of tumor growth in gastrointestinal PDX models. A single intravenous dose of 60 mg/kg of HDP-201 was well tolerated in cynomolgus monkeys, with no severe toxicity.

These findings underscore the potential of HDP-201 as a promising new therapeutic option for GCC-positive gastrointestinal malignancies.

Talk (Minisymposium): In silico optimized NAMPT inhibitor for targeted delivery by ADC as novel therapeutic modality for treatment of liquid and solid malignancies

Nearly half of the US Food and Drug Administration (FDA) approved ADCs are based on microtubule inhibitors, that selectively target dividing cancer cells but fail to eradicate non-dividing tumor stem cells, potentially leading to resistance and tumor relapse.

Inhibition of NAMPT, the rate-limiting enzyme in the salvage biosynthetic pathway of NAD+ starting from nicotinamide, induces cell death due to energy shortage in both dividing and non-dividing cell populations. This is a promising approach to overcome current therapy limitations by utilizing novel payloads. 

ADCs based on in silico designed NAMPTi as payloads show promising in vitro and in vivo results, highlighting the potential of NAMPT inhibition as an emerging MOA in ADC technology that enhances the targeted drug delivery to different cell lines.

About Heidelberg Pharma
Heidelberg Pharma is a biopharmaceutical company working on a new treatment approach in oncology and developing novel drugs based on its ADC technologies for the targeted and highly effective treatment of cancer. ADCs are antibody-drug conjugates that combine the specificity of antibodies with the efficacy of toxins to fight cancer. Selected antibodies are loaded with cytotoxic compounds, the so-called payloads, that are transported into diseased cells. Inside the cells, the toxins then unleash their effect and kill the diseased cells.

Heidelberg Pharma uses several compounds and has built up an ADC toolbox that overcomes tumor resistance via numerous pathways and addresses different types of cancer using various antibodies. The goal is to develop targeted and highly effective ADCs for the treatment of a variety of malignant hematologic and solid tumors.

Heidelberg Pharma is the first company to use the compound Amanitin from the green death cap mushroom in cancer therapy. The biological mechanism of action of the toxin represents a new therapeutic modality and is used as a compound in the Amanitin-based ADC technology, the so-called ATAC technology.

The company is based in Ladenburg, Germany, and is listed on the Frankfurt Stock Exchange: ISIN DE000A11QVV0 / WKN A11QVV / Symbol HPHA. More information is available at .

ATAC^® is a registered trademark of Heidelberg Pharma Research GmbH.

ITAC™, ETAC™ are pending trademark applications of Heidelberg Pharma Research GmbH.

This communication contains certain forward-looking statements relating to the Company's business, which can be identified by the use of forward-looking terminology such as "estimates", "believes", "expects", "may", "will”, "should”, "future", "potential" or similar expressions or by a general discussion of the Company's strategy, plans or intentions. Such forward-looking statements involve known and unknown risks, uncertainties and other factors, which may cause our actual results of operations, financial condition, performance, achievements, or industry results, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Given these uncertainties, prospective investors and partners are cautioned not to place undue reliance on such forward-looking statements. We disclaim any obligation to update any such forward-looking statements to reflect future events or developments.