Harpoon Therapeutics has completed the planned enrolment of patients in the Phase I clinical trial of HPN217 for the treatment of relapsed/refractory multiple myeloma.

The trial intends to enrol additional patients who are currently in screening.

The dose escalation, open-label, multicentre study will assess the pharmacokinetics (PK), tolerability, safety, and clinical activity of HPN217 that targets the B-cell maturation antigen (BCMA).

Patients with relapsed/refractory multiple myeloma who previously received at least three systemic treatments, including an anti-CD38 antibody, an immunomodulatory drug, and a proteasome inhibitor, are enrolled in the study.

In addition, patients previously exposed to BCMA therapy are included in the study.

Characterisation of PK, tolerability, safety, and determining the recommended Phase II dose are the primary objectives of the study.

Harpoon Therapeutics president and CEO Julie Eastland said: “We are pleased to have achieved this important milestone for Harpoon, with the enrolment of the first of our two Tri-specific T cell Activating Construct (TriTAC) clinical compounds having completed dose escalation as planned.

“The identification of the recommended dose(s) for Phase II and the presentation of Phase I data is anticipated by the end of 2023.”

Harpoon is also developing a pipeline of TriTACs compounds for treating haematologic malignancies and solid tumours.

AbbVie can exercise its option to license HPN217 after completion of the Phase I study, as per the licensing agreement signed between the company and Harpoon in November 2019.