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 and data from its second 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 provide the first clinical evidence that Heidelberg Pharma’s Amanitin-based ATAC technology can generate meaningful antitumor activity with a favorable safety profile in heavily pretreated patients, potentially opening a new therapeutic modality for difficult-to-treat blood cancers.
The oral presentation, scheduled for Saturday, December 12, will detail the first-in-human Phase 1/2a study of pamlectabart tismanitin, an anti-BCMA antibody-Amanitin drug conjugate for relapsed or refractory multiple myeloma (RRMM). The study’s Phase I dose-escalation part, which included ten patient cohorts, was completed in April 2026, and the recommended Phase 2 dose (RP2D) for the expansion phase was determined. According to the company, pamlectabart tismanitin demonstrated consistent clinical activity and a favorable safety profile in heavily pretreated RRMM patients, supporting its potential as a novel BCMA-targeted ADC therapy. The abstract is available in the ASH® ANNUAL PROGRAM.
The poster presentation on Sunday, December 13, will cover HDP-102, a first-in-class CD37-targeted Amanitin-based ADC for relapsed or refractory B-cell malignancies. In the ongoing Phase I study, three patients were treated at 40 µg/kg in the first cohort; treatment was well tolerated, and initial signs of biological activity were observed even at this very low dose. Two patients showed stabilization of disease with regression and reduction of lymph nodes, leading the safety committee to recommend increasing the dose to 65 µg/kg in cohort 2. However, Heidelberg Pharma had already decided in September 2025 to discontinue the study and is now exploring partnership opportunities to continue the program. The HDP-102 abstract is also accessible via the ASH® ANNUAL PROGRAM.
The ASH Annual Meeting is one of the most important venues for hematology research, and presenting both candidates there underscores the potential of Heidelberg Pharma’s ATAC platform. Pamlectabart tismanitin has already received Orphan Drug Designation and Fast Track Designation from the FDA, which could expedite its development. The new data may help the company attract partners for its other ATAC candidates, including HDP-103 for metastatic castration-resistant prostate cancer and HDP-104 for gastrointestinal tumors, both of which have completed preclinical development and are available for partnering. More information about Heidelberg Pharma is available at http://www.heidelberg-pharma.com/.
