Heidelberg Pharma (HPHA) Status Update summary

Clinical development highlights

• HDP-101, a novel ADC targeting BCMA with an α-amanitin payload, shows strong efficacy in heavily pretreated multiple myeloma patients, including those with prior BCMA therapies.

• The unique mechanism of action enables killing of dormant and low-antigen-expressing myeloma cells, overcoming resistance seen with other therapies.

• In the highest dose cohort (140 µg/kg), 4 of 7 patients responded, with rapid and deep responses, and no grade 3/4 toxicities observed.

• Adjusted dosing regimens have mitigated early thrombocytopenia without compromising efficacy.

• No ocular, renal, or significant liver toxicity has been observed, and the safety profile supports combination therapy potential.

Regulatory and strategic updates

• Fast track designation was recently granted by the US FDA, validating the clinical results and expediting development.

• Development plans include monotherapy in post-BCMA settings, combination regimens in earlier lines, and studies in high-risk (17p deletion) populations.

• Subgroup analyses for 17p deletion and further pivotal studies are planned after phase IIa completion.

• The company is prioritizing HDP-101 clinical trials and may sequence other programs based on available resources.

• International expansion is ongoing, with a Chinese partner preparing for phase II registration trials.

Efficacy and safety data

• Across all cohorts, the overall response rate is 38%, with the highest dose cohort showing a 57% response rate and 29% complete remissions.

• Responses are durable, with some patients achieving remission for over two years.

• The safety profile is favorable, with minimal high-grade toxicities and no cumulative or delayed toxicity observed to date.

• The drug is well tolerated, with most adverse events being mild and transient.

• The mild safety profile and outpatient suitability differentiate it from CAR-T and bispecific therapies.