Harpoon Therapeutics Announces Completion of Planned Patient Enrollment in Phase 1 Study of HPN217 in Relapsed/Refractory Multiple Myeloma

SOUTH SAN FRANCISCO, Calif., June 27, 2023 (GLOBE NEWSWIRE) -- Harpoon Therapeutics, Inc. (Nasdaq: HARP), a clinical-stage immuno-oncology company developing novel T cell engagers, today announced the completion of planned patient enrollment in the Phase 1 dose escalation study evaluating the safety, tolerability, and pharmacokinetics of HPN217 in patients with relapsed/refractory multiple myeloma. Additional patients currently in screening will also be allowed to enroll.

“Completing enrollment in the Phase 1 trial of HPN217 is an important step towards potentially bringing this therapy to patients with advanced disease who have progressed after prior treatments," said Luke Walker, M.D., Chief Medical Officer of Harpoon Therapeutics. “I would like to thank our patients and their caregivers, as well as our clinical partners and dedicated team of employees who have participated in this Phase 1 trial and advanced the development of HPN217.“

“We are pleased to have achieved this important milestone for Harpoon, with the enrollment of the first of our two TriTAC clinical compounds having completed dose escalation as planned,” said Julie Eastland, President and CEO of Harpoon Therapeutics. “The identification of the recommended dose(s) for Phase 2 and the presentation of Phase 1 data is anticipated by the end of 2023.”

About the HPN217 Clinical Trial

HPN217 is being evaluated in an ongoing Phase 1, multicenter, open-label dose escalation study designed to evaluate safety, tolerability, pharmacokinetics (PK) and clinical activity in patients with relapsed/refractory multiple myeloma who have had at least three prior systemic treatments, including a proteasome inhibitor, an immunomodulatory drug and an anti-CD38 antibody, including patients with prior exposure to BCMA therapy. Primary objectives are characterization of safety, tolerability, PK and determination of the recommended Phase 2 dose.

For additional information about the trial, please visit using the identifier NCT04184050.

About HPN217

HPN217 targets B-cell maturation antigen (BCMA) and is based on Harpoon’s proprietary Tri-specific T cell Activating Construct (TriTAC®) platform designed to recruit a patient’s own immune cells to kill tumor cells. HPN217 is being evaluated in an ongoing Phase 1, multicenter, open-label dose escalation study designed to evaluate safety, tolerability, pharmacokinetics (PK) and clinical activity in patients with relapsed/refractory multiple myeloma who have had at least three prior systemic treatments.

In November 2019, Harpoon Therapeutics and AbbVie announced a licensing agreement and option to advance HPN217 and expand an existing discovery collaboration. Under the terms of the agreement, AbbVie may exercise its option to license HPN217 after completion of the Phase 1 clinical trial.

In March 2022, the FDA granted Fast Track designation to HPN217, underscoring its potential to address a serious unmet medical need for patients with relapsed, refractory multiple myeloma.

About Harpoon Therapeutics

Harpoon Therapeutics is a clinical-stage immuno-oncology company developing a novel class of T cell engagers that harness the power of the body’s immune system to treat patients suffering from cancer and other diseases. T cell engagers are engineered proteins that direct a patient’s own T cells to kill target cells that express specific proteins, or antigens, carried by the target cells. Using its proprietary Tri-specific T cell Activating Construct (TriTAC^®) platform, Harpoon is developing a pipeline of novel TriTACs initially focused on the treatment of solid tumors and hematologic malignancies. Harpoon has also developed a proprietary ProTriTAC™ platform, which applies a prodrug concept to its TriTAC platform to create a therapeutic T cell engager that remains inactive until it reaches the tumor. Harpoon’s third proprietary technology platform, extended release TriTAC-XR, is designed to mitigate cytokine release syndrome. For additional information about Harpoon Therapeutics, please visit and follow us on and .

Cautionary Note on Forward-looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “anticipate,” “may,” “expect,” “plan,” “potential,” “further,” “will,” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Harpoon Therapeutics’ expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties that could cause Harpoon Therapeutics’ clinical development programs, future results or performance to differ significantly from those expressed or implied by the forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements about the expected progress, results, and plans pertaining to Harpoon Therapeutics’ clinical trials, including timing, scope, design, enrollment plans and interim results of clinical trials and the safety and tolerability profile of product candidates, the association of interim clinical data and preclinical results with potential treatment outcomes, achievement of future milestones, and other statements that are not historical fact. Many factors may cause differences between current expectations and actual results, including unexpected safety or efficacy data observed during clinical studies, preliminary data and trends may not be predictive of future data or results, may not demonstrate safety or efficacy or lead to regulatory approval by the FDA or other regulatory agencies, clinical trial site activation or enrollment rates that are lower than expected, changes in expected or existing competition, changes in the regulatory environment, the uncertainties and timing of the regulatory approval process, the timing and results of unexpected litigation or other disputes, and the sufficiency of Harpoon Therapeutics’ cash resources, including that Harpoon Therapeutics may not achieve the expected benefits of its restructuring or may incur unexpected additional expenses in connection with such restructuring. These and other factors that may cause Harpoon Therapeutics’ actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Harpoon Therapeutics’ filings with the U.S. Securities and Exchange Commission, including under “Risk Factors” in Harpoon Therapeutics’ quarterly report on Form 10-Q for the quarter ended March 31, 2023, and future filings by Harpoon Therapeutics. Except as required by law, Harpoon Therapeutics assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

Contacts:

ICR Westwicke:

Robert H. Uhl

Managing Director

858-356-5932