PRESS RELEASE

Heidelberg Pharma Secures Patent for the Use of its ADC Technology Platform

Ladenburg, Germany, 15 November 2023 – Heidelberg Pharma AG (FSE: HPHA) today announced that its subsidiary Heidelberg Pharma Research GmbH has been granted a patent covering site-specific ATAC conjugates by the European Patent Office (EPO). Site-specific ATAC conjugates comprise a genetically engineered antibody to which Heidelberg Pharma’s proprietary amatoxin payloads can be coupled via specific linkers. The European patent also covers a method for the synthesis of such conjugates as well as their use in the treatment of diseases. It has a term until 2036. ATAC conjugates are antibody drug conjugates (ADCs) based on the toxin Amanitin.

The patent protects the use of Amanitin-based ADCs for research and development, as well as for the use in clinical studies and the commercialization of resulting product candidates.

Professor Andreas Pahl, Chief Scientific Officer of Heidelberg Pharma, comments: "We are very pleased that this patent has been granted, as it protects essential aspects of our ATAC technology, as e.g. improved safety and tolerability of our product candidates."

About Heidelberg Pharma's proprietary ATAC technology

Antibody drug conjugates (ADCs) combine the high affinity and specificity of antibodies with the potency of cytotoxic small molecules for the treatment of cancer. ATACs are ADCs whose active ingredient is the mushroom toxin Amanitin. Amanitin inhibits mRNA transcription by binding to RNA polymerase II, a mechanism that is crucial for the survival of eukaryotic cells. In preclinical testing, ATACs have been shown to be highly efficacious, overcoming frequently encountered resistance mechanisms and combating even quiescent tumor cells.

About Heidelberg Pharma

Heidelberg Pharma is an oncology specialist and the first company to develop the toxin Amanitin into cancer therapies using its proprietary ATAC technology and to advance the biological mode of action of the toxin as a novel therapeutic principle. The proprietary technology platform is being applied to develop the Company’s own therapeutic ATACs as well as in third-party collaborations. The lead candidate HDP-101 is a BCMA ATAC in clinical development for multiple myeloma. Further ATAC candidates are being developed against different targets such as CD37, PSMA and GCC in the indications non-Hodgkin's lymphoma, metastatic castration-resistant prostate cancer or gastrointestinal tumors such as colorectal cancer.

Heidelberg Pharma AG 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 in the EU and the USA.

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.