from Heidelberg Pharma AG (ETR:HPHA)
EQS-Adhoc: Heidelberg Pharma AG: Heidelberg Pharma Determines Recommended Dose for Phase II Trial with ADC Candidate HDP-101
EQS-Ad-hoc: Heidelberg Pharma AG / Key word(s): Other
Heidelberg Pharma AG: Heidelberg Pharma Determines Recommended Dose for Phase II Trial with ADC Candidate HDP-101
09-Apr-2026 / 14:26 CET/CEST
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Ad hoc announcement - Disclosure of inside information under Article 17 of Regulation (EU) No 596/2014
Heidelberg Pharma Determines Recommended Dose for Phase II Trial with ADC Candidate HDP-101
- Phase I part of trial with pamlectabart tismanitin (HDP-101) will now be concluded as the recommended Phase II dose (RP2D) has been selected based on safety and tolerability data
- Initiation of Phase IIa in Multiple Myeloma planned in the next few weeks
- Further details will be published at a future scientific conference
Ladenburg, Germany, 9 April 2026 - Heidelberg Pharma AG (FSE: HPHA), a clinical-stage biotech company developing innovative Antibody Drug Conjugates (ADCs), today announced the determination of the recommended Phase II dose (RP2D) in its Phase I/IIa study with pamlectabart tismanitin (HDP-101) for the treatment of relapsed or refractory multiple myeloma. Heidelberg Pharma’s Benefit and Risk Assessment team agreed with the recommendation by the study’s Safety Review Committee (SRC), which had conducted a comprehensive review of safety, tolerability and pharmacokinetic (PK) data from the Company’s ongoing Phase I/IIa trial.
Across evaluated dose levels, pamlectabart tismanitin was well-tolerated and a maximum tolerated dose was not reached. The candidate showed promising efficacy results in the last dose cohorts; therefore, the SRC recommended stopping further dose escalation and accrual into the Phase I study part and proceeding to the study for the Phase IIa dose expansion part.
Heidelberg Pharma will release safety and efficacy details of the dose escalation and the selection of the RP2D at the next potential scientific conference.
The Phase IIa part of the study will include up to 30 patients on the selected dose; patient enrollment is planned to start in existing study centers in the next few weeks. The objectives are to further evaluate the preliminary anti-tumor activity of pamlectabart tismanitin along with the drug’s safety and pharmacokinetic and dynamic behaviour.
End of Inside Information
Explanation, why the information directly concerns that issuer:
About pamlectabart tismanitin
Pamlectabart tismanitin consists of an anti-BCMA antibody, a specific linker and the Amanitin toxin. BCMA (B-cell maturation antigen) is a surface protein that is highly expressed in multiple myeloma cells and to which BCMA antibodies specifically bind. The candidate has been evaluated since February 2022 in a Phase I/IIa non-randomized, open-label, dose escalation trial clinical trial for treatment of relapsed or refractory multiple myeloma. The study is designed to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of pamlectabart tismanitin in this patient population.
In the last fully evaluated cohort, cohort 8, encouraging signs of clinical activity have been observed. Four patients showed biological activity, with one partial response, one very good partial response and two stringent complete remissions.
Pamlectabart tismanitin has been granted Fast Track designation as well as Orphan Drug Designation (ODD). Both designations underline the significance of this candidate for the treatment of patients with multiple myeloma.
About Heidelberg Pharma
Heidelberg Pharma is the first company to use the compound Amanitin from the green death cap mushroom in cancer therapy. The biological mechanism of action of the toxin represents a new therapeutic modality and is used as a compound in the Amanitin-based ADC technology, the so-called ATAC technology.
Lead candidate HDP-101 (INN: pamlectabart tismanitin) is a BCMA ATAC in clinical development for multiple myeloma. The candidate has been granted Orphan Drug Designation and Fast Track Designation from the FDA. A second ATAC candidate, HDP-102 is in clinical development stage in 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. These programs are available for partnering.
The company 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.
| Contact Heidelberg Pharma AG Sylvia Wimmer Senior Director Corporate Communications Tel.: +49 6203 1009 1004 E-Mail: investors@hdpharma.com Gregor-Mendel-Str. 22, 68526 Ladenburg | IR/PR-Support MC Services AG Katja Arnold (CIRO) Managing Director & Partner Tel.: +49 89 210 228-40 E-Mail: katja.arnold@mc-services.eu |
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.
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| Language: | English |
| Company: | Heidelberg Pharma AG |
| Gregor-Mendel-Str. 22 | |
| 68526 Ladenburg | |
| Germany | |
| Phone: | +49 (0)89 41 31 38 - 0 |
| Fax: | +49 (0)89 41 31 38 - 99 |
| E-mail: | investors@hdpharma.com |
| Internet: | www.heidelberg-pharma.com |
| ISIN: | DE000A11QVV0 |
| WKN: | A11QVV |
| Listed: | Regulated Market in Frankfurt (Prime Standard); Regulated Unofficial Market in Dusseldorf, Munich, Stuttgart, Tradegate BSX |
| EQS News ID: | 2305902 |
| End of Announcement | EQS News Service |
2305902 09-Apr-2026 CET/CEST