Heidelberg Pharma AG, a clinical-stage company developing innovative Antibody Drug Conjugates (ADCs), announced it will present new data from its Phase I/IIa clinical study with its lead Amanitin-based ADC candidate, pamlectabart tismanitin (HDP-101), in an oral presentation, as well as data from its second clinical candidate, HDP-102, during the poster abstract session of the 68th Annual Meeting of the American Society of Hematology (ASH), being held in New Orleans, USA, from 12 to 15 December 2026.
The oral presentation will detail the first-in-human phase 1/2a study of pamlectabart tismanitin, an amanitin-based BCMA-targeting ADC, including recommended phase 2 dose (RP2D) selection and preliminary antitumor activity in relapsed/refractory multiple myeloma (RRMM). The presentation will be given by Professor Marc-Steffen Raab, MD, on Saturday, 12 December 2026, at the Ernest N. Morial Convention Center. Pamlectabart tismanitin is an anti-BCMA antibody-Amanitin drug conjugate for the treatment of RRMM, a bone marrow cancer with a high unmet medical need. The Phase I part of the study included ten patient cohorts and was completed in April 2026, and the recommended dose for the Phase IIa expansion part was determined. The Phase IIa is progressing as planned. According to the company, pamlectabart tismanitin demonstrated consistent clinical activity with a favorable safety profile in heavily pretreated RRMM patients, supporting the potential of the candidate as a novel payload BCMA-targeted ADC therapy.
The poster presentation will cover HDP-102, a first-in-class CD37-targeted amanitin-based ADC, which demonstrated translational activity and favorable early safety and efficacy in relapsed/refractory B-cell malignancies. Dr. Irina Mocanu, MD, will present the data on Sunday, 13 December 2026. HDP-102 targets CD37, which is overexpressed on B-cell lymphoma cells. Preclinical studies have shown excellent anti-tumor efficacy in in vivo studies as well as good tolerability. HDP-102 is intended to be developed for specific indications of non-Hodgkin lymphoma. In 2025, Heidelberg Pharma announced the dosing of the first patient with HDP-102. Three patients were treated with 40 µg/kg in the first cohort. The treatment was well tolerated, and initial signs of biological activity have been observed already at the very low dose. Two patients showed stabilization of the disease with regression and reduction of lymph nodes. The safety committee recommended increasing the dose of HDP-102 to 65 µg/kg in cohort 2. However, in line with Heidelberg Pharma’s strategic decision from September 2025 to discontinue the study, the company is exploring partnership opportunities to support the continuation of the program.
The data presentations are significant for the multiple myeloma and lymphoma communities, as they provide early clinical validation of Heidelberg Pharma’s ATAC technology, which uses Amanitin, a compound derived from the green death cap mushroom, as a novel payload. If the results continue to show a favorable safety and efficacy profile, pamlectabart tismanitin could offer a new treatment option for patients with relapsed or refractory multiple myeloma, while HDP-102 could address unmet needs in non-Hodgkin lymphoma. The company’s pipeline also includes HDP-103 against metastatic castration-resistant prostate cancer and HDP-104 targeting gastrointestinal tumors, both of which have completed preclinical development and are available for partnering. Heidelberg Pharma is based in Ladenburg, Germany, and is listed on the Frankfurt Stock Exchange. More information is available at http://www.heidelberg-pharma.com/. The full abstract details are available in the ASH® ANNUAL PROGRAM.
