Heidelberg Pharma to Present Promising New Clinical Data on its Lead ATAC Candidate HDP-101 at EHA 2025

PRESS RELEASE

Heidelberg Pharma to Present Promising New Clinical Data on its Lead ATAC Candidate HDP-101 at EHA 2025

• HDP-101 demonstrated complete response in one female patient from cohort 5
• R&D Webinar to be hosted on 17 June 2025

Ladenburg, Germany, 14 May 2025 – Heidelberg Pharma AG (FSE: HPHA), a clinical-stage biotech company developing innovative Antibody Drug Conjugates (ADCs), today announced that it will be presenting new clinical data on its lead Amanitin-based ADC candidate, HDP-101 at the 30^thEuropean Hematology Association (EHA) Congress, taking place in Milan, Italy, from 12 – 15 June 2025.

The Amanitin-based ADC candidate HDP-101 is being evaluated in a Phase I/IIa clinical trial for the treatment of relapsed or refractory Multiple Myeloma. HDP-101 is showing encouraging results, including an ongoing complete response in a female patient from cohort 5 who had been heavily pretreated and who has been treated continuously with HDP-101 alone for more than 19 months.

In addition, promising biological activity and objective improvements were observed in several patients, underscoring the potential of HDP-101 as a treatment option for Multiple Myeloma. The study is advancing in cohort 8 at a dose of 140 µg/kg.

EHA 2025 Congress

Poster Presentation Title: The Anti-BCMA Antibody Drug Conjugate HDP-101 with a Novel Amanitin Payload Shows Promising Data in Relapsed/Refractory Multiple Myeloma in a Phase I/IIa clinical trial as it advances into Cohort 7 

R&D Webinar “Pioneering New Treatment Options in Relapsed or Refractory Multiple Myeloma with a New Amanitin-based ADC”

Following the EHA Congress, Heidelberg Pharma will host an R&D webinar on 17 June at 17:00 CEST to provide further insights into the ongoing clinical trial of its lead candidate, HDP-101.

The R&D webinar will include presentations from Heidelberg Pharma’s management team, alongside Key Opinion Leaders (KOLs) in the field of Multiple Myeloma, Jonathan Kaufman, MD, Associate Professor of Hematology & Medical Oncology, Emory University School of Medicine, Atlanta, USA and Professor Marc-Steffen Raab, MD, Director Heidelberg Myeloma Center, Heidelberg University Hospital, Heidelberg, Germany. 

Attendees are invited to submit questions in advance or participate in a live Q&A session following the presentation.

For further information about the R&D webinar or to register your interest, please contact investors@hdpharma.com or register using the link below:

https://beacon-intelligence.com/webinars/pioneering-new-treatment-options-in-relapsed-or-refractory-multiple-myeloma-with-a-new-amanitin-based-adc/

A recording of the webinar will be made available shortly after the event in the section “Press & Investors > Conferences & Calendar > Conferences & Presentations” of the Company website shortly after the event.

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 www.heidelberg-pharma.com.

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.