Heidelberg Pharma to Present Promising Clinical Data for Multiple Myeloma ADC Candidate HDP-101

Heidelberg Pharma AG announced the presentation of new clinical data from its ongoing Phase I/IIa clinical study evaluating its lead Amanitin-based ADC candidate, HDP-101 (INN: pamlectabart tismanitin), at the 16th Annual World ADC Congress in San Diego, California. The data show objective responses and promising anti-tumor activity observed in several patients across multiple cohorts in the ongoing trial, reinforcing the therapeutic potential and safety profile of HDP-101 in relapsed or refractory multiple myeloma.

HDP-101 is an anti-BCMA antibody-drug conjugate being investigated for the treatment of relapsed or refractory multiple myeloma, a bone marrow cancer with a high unmet medical need. Phase I of the ongoing study is a dose-escalation trial designed to determine the optimal and safe dose level of HDP-101 in preparation for subsequent Phase II clinical evaluation. Professor Andreas Pahl, Chief Executive Officer of Heidelberg Pharma, will present an update from patient cohort 8 including efficacy data of the open-label, multicenter Phase I/IIa study.

The presentation titled "From Bench to Breakthrough: The Evolution of Amanitin ADCs - Insights from HDP-101 Phase I/II & the Future of Payload Differentiation" will be delivered on Wednesday, 5 November 2025, at 5:00 pm PST at the Town & Country San Diego location. Following the World ADC Congress, Heidelberg Pharma will host an R&D webinar on 11 November 2025 at 05:00 pm CET for investors, analysts, and media. The webinar will feature presentations by the Heidelberg Pharma management team alongside Key Opinion Leader Professor Marc-Steffen Raab, Head of the Myeloma Center at the University Hospital Heidelberg and clinical investigator of the study.

Webinar participants will have the opportunity to submit questions in advance or ask questions live during the event. For further information on the R&D webinar, or to register your attendance, please use the link here. A recording of the R&D webinar will be accessible via the press & investor section of the Company website after the event. More information about the company is available at www.heidelberg-pharma.com.