PRESS RELEASE

Heidelberg Pharma: New Clinical Data on Lead ADC Candidate HDP-101 Presented at IMS 2024 Demonstrating Complete Remission in One Patient

• Data from the study with the lead ADC candidate, HDP-101, show elimination of tumor cells in one patient
• Clinical data from IMS will be presented in R&D webinar on 15 October at 17:00 CEST / 11:00 EDT

Ladenburg, Germany, 1 October 2024 – Heidelberg Pharma AG (FSE: HPHA), a clinical stage company developing innovative Antibody Drug Conjugates (ADCs), today announces that new clinical data from its lead Amanitin-based ADC candidate, HDP-101, were presented at the International Myeloma Society (IMS) Annual Meeting, held in Rio de Janeiro, Brazil on 27 September 2024.

HDP-101 is being evaluated in an ongoing Phase I/IIa clinical trial in the indication of relapsed or refractory multiple myeloma, a bone marrow cancer with a high unmet medical need. Clinical data from the fifth cohort demonstrated complete remission in one patient who had been heavily pre-treated. This patient showed an objective improvement (“partial response”) in the 2nd cycle of treatment and complete remission was confirmed after the 11th cycle.

In addition, several patients showed promising biological activity and an objective improvement demonstrating the potential of HDP-101 as a treatment option for patients with the disease.

Following the presentation at IMS, Heidelberg Pharma will host an R&D webinar on 15 October 2024 at 17:00 CEST/ 11:00 EDT, for investors, analysts, and media.

The R&D webinar will feature presentations by the Heidelberg Pharma management team, alongside Key Opinion Leaders (KOLs) in the myeloma field: Shambavi Richard, MD, Associate Professor Icahn School of Medicine at Mount Sinai Hospital, New York, USA and Robert Z. Orlowski, MD, PhD, (Ad Interim) Director of Myeloma, and Professor of Medicine in the Departments of Lymphoma/Myeloma and Experimental Therapeutics, University of Texas, Houston, Texas, and principal investigator at MD Anderson Cancer Center, Houston, Texas, USA.

Webinar participants will have the opportunity to submit questions in advance of the webinar or ask questions live during the event.

For further information on the R&D webinar, or to register your attendance, please use the link below:

A live recording of the R&D webinar will be accessible via the press & investor section of the Company website.

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. It offers the opportunity to overcome therapy resistance and also eliminate dormant tumor cells, which could lead to significant progress in cancer therapy - even for patients who no longer respond to other treatment. The Amanitin-based ADC development candidates are called ATACs.

The most advanced product candidate HDP-101 is a BCMA-ATAC for the indication multiple myeloma, which is currently in clinical development.

The first candidate that Heidelberg Pharma is developing with a toxin other than Amanitin is HDP-201, an exatecan-based ADC. Exatecan is a topoisomerase I inhibitor that has proven itself in cancer therapy and is used in two already approved ADCs. It differs in its mode of action from that of Amanitin and thus expands the company's range of compounds.

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.

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, or 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.