PRESS RELEASE

Heidelberg Pharma Announces New Clinical Data on Lead ATAC Candidate HDP-101 to be Presented at International Myeloma Society Annual Meeting 2024

Ladenburg, Germany, 23 September 2024 – Heidelberg Pharma AG (FSE: HPHA), a clinical stage company developing innovative Antibody Drug Conjugates (ADCs), today announces that new data from its Phase I/IIa clinical study with lead Amanitin-based ADC candidate, HDP-101, will be presented at the 21^st International Myeloma Society (IMS) Annual Meeting, being held in Rio De Janeiro, Brazil on 25 to 28 September 2024.

HDP-101 is an Anti-BCMA antibody-Amanitin drug conjugate for the treatment of relapsed or refractory multiple myeloma, a bone marrow cancer with a high unmet medical need. Phase I of the trial is a dose escalation study to determine an optimal and safe dose level of HDP-101 in patients in preparation for Phase II clinical studies.

Professor Marc-Steffen Raab, Head of the Myeloma Center at the University Hospital Heidelberg and clinical investigator of the study will present new clinical findings from five patient cohorts of the ongoing open-label, multicenter Phase I/IIa trial evaluating HDP-101 in multiple myeloma.

Details of the presentation are as follow:

Presentation title: The Anti-BCMA Antibody-Drug Conjugate HDP-101 with a Novel Amanitin Payload Shows Promising Initial First in Human Results in Relapsed Multiple Myeloma (OA – 60)

Previous data from cohort five have demonstrated biological activity in three out of five patients, and an objective improvement in disease was detected (\"partial remission\"). The trial is currently treating patients in its sixth cohort with further data to be presented at upcoming scientific conferences.

Following the presentation at IMS, Heidelberg Pharma will host a R&D Webinar on 15 October 2024 at 17:00 pm CEST/ 11:00 am ET, for investors, analysts and media. Further registration information will be announced in due course.

About Heidelberg Pharma

Heidelberg Pharma develops novel drugs based on its ADC technologies for the targeted and highly effective treatment of cancer. ADCs are antibody-drug conjugates that combine the high affinity and specificity of antibodies with the efficacy of toxins to fight cancer. Selected antibodies are loaded with various toxins, the so-called payloads, that are transported into diseased cells. Inside the cells, the toxins then unleash their effect and kills the diseased cells.

Heidelberg Pharma is the first company to use the mushroom toxin Amanitin in cancer therapies by exploiting the toxin's biological mechanism of action with its innovative ATAC technology as a new therapeutic modality. It offers the opportunity to not only overcome resistance of cancer cells against therapeutic agents currently used, but also has the ability to eliminate dormant tumor cells. This could lead to significant advances in cancer therapy - even for patients who no longer respond to any other treatment. The most advanced product candidate HDP-101 is an BCMA-ATAC for the indication multiple myeloma, which is currently in clinical development.

In addition to Amanitin, other payloads are expanding the ADC platform technologies of Heidelberg Pharma to develop targeted and highly effective ADCs for the treatment of a variety of malignant hematologic and solid tumors.

Heidelberg Pharma AG is a biopharmaceutical company based in Ladenburg, Germany, and is listed on the Frankfurt Stock Exchange: ISIN DE000A11QVV0 / WKN A11QVV / Symbol HPHA. More information is available at www.heidelberg-pharma.com

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

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