Heidelberg Pharma AG (FSE: HPHA), a clinical-stage company developing innovative Antibody Drug Conjugates (ADCs), announced it will present new clinical data from its Phase I/IIa study of lead candidate pamlectabart tismanitin (HDP-101) in an oral presentation, along with data from its second clinical candidate, HDP-102, in a poster session at the 68th Annual Meeting of the American Society of Hematology (ASH), taking place in New Orleans from December 12 to 15, 2026. The presentations are significant because they showcase clinical validation of Heidelberg Pharma's Amanitin-based ATAC technology, which represents a new therapeutic modality for cancer treatment.
Pamlectabart tismanitin is an anti-BCMA antibody-Amanitin drug conjugate being developed for relapsed or refractory multiple myeloma (RRMM), a bone marrow cancer with high unmet medical need. The oral presentation, titled "First-in-human phase 1/2a study of pamlectabart tismanitin (HDP-101), an amanitin-based BCMA-targeting antibody-drug conjugate (ADC): Recommended phase 2 dose (RP2D) selection and preliminary antitumor activity in relapsed/refractory multiple myeloma (RRMM)," will be delivered by Professor Marc-Steffen Raab, MD, on Saturday, December 12, 2026. The Phase I dose-escalation portion, which included ten patient cohorts, was completed in April 2026, and the recommended Phase 2 dose (RP2D) was determined. The Phase IIa expansion study 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 its potential as a novel payload BCMA-targeted ADC therapy. The abstract is available in the ASH® ANNUAL PROGRAM.
The poster presentation will feature HDP-102, a first-in-class CD37-targeted amanitin-based ADC for relapsed/refractory B-cell malignancies. Dr. Irina Mocanu, MD, will present the data on Sunday, December 13, 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 and good tolerability. In 2025, Heidelberg Pharma announced dosing of the first patient with HDP-102. Three patients were treated with 40 µg/kg in the first cohort; treatment was well tolerated, and initial signs of biological activity were observed 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 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 abstract is available in the ASH® ANNUAL PROGRAM.
Heidelberg Pharma is the first company to develop cancer therapies using Amanitin, a compound derived from the green death cap mushroom. The biological mechanism of action of the toxin represents a new therapeutic modality and is used in its Amanitin-based ADC technology, known as ATAC. Lead candidate HDP-101 has been granted Orphan Drug Designation and Fast Track Designation from the FDA. A second ATAC candidate, HDP-102, is in clinical development for non-Hodgkin lymphoma. HDP-103 against metastatic castration-resistant prostate cancer and HDP-104 targeting gastrointestinal tumors such as colorectal cancer have completed preclinical development and are available for partnering. The company is based in Ladenburg, Germany, and is listed on the Frankfurt Stock Exchange. More information is available at http://www.heidelberg-pharma.com/.
The data to be presented at ASH 2026 are important for patients with multiple myeloma and B-cell malignancies, as they may offer new treatment options for relapsed or refractory disease. For the industry, the results could further validate Amanitin-based ADCs as a promising class of cancer therapies. Heidelberg Pharma's ongoing Phase IIa study of pamlectabart tismanitin and the partnership discussions for HDP-102 will be key to watch.
