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AH: Heidelberg Pharma Determines Recommended Dose for Phase II Trial with ADC Candidate HDP-101

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  • 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.

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