Harpoon Therapeutics and Roche to Collaborate on Clinical Trials to Study Novel Immuno-Oncology Combination for Small Cell Lung Cancer

HPN328, Harpoon’s DLL3-targeting T cell engager, to be evaluated in combination with anti-PD-L1 antibody in patients with small cell lung cancer

SOUTH SAN FRANCISCO, Calif., May 02, 2022 (GLOBE NEWSWIRE) — Harpoon Therapeutics, Inc. (Nasdaq: HARP), a clinical-stage immunotherapy company developing novel T cell engagers, today announced that it has entered into a clinical supply agreement with F. Hoffmann-La Roche Ltd (Roche) to supply atezolizumab (Tecentriq^®) for use in the Company’s HPN328, a DLL3 targeting TriTAC^®, clinical development program.

“We are pleased to enter into this clinical supply agreement with Roche as it enables us to investigate the impact of HPN328 on solid tumors in combination with atezolizumab and provide further insight into the capabilities of our TriTAC technology platform,” stated Julie Eastland, President and CEO, Harpoon Therapeutics. “We are pleased with the compelling profile emerging in our monotherapy study and we plan to initiate combination trials in multiple lines of therapy for patients with small cell lung cancer, a disease with unmet medical need.”

Under this agreement, Harpoon is the sponsor of the anticipated clinical trials, and Roche will supply atezolizumab.

About HPN328

HPN328 is a DLL3 targeting TriTAC^® being studied as a single agent in an ongoing clinical trial for patients with small cell lung cancer, neuroendocrine and other DLL3-associated tumors. The Phase 1/2 trial is an open-label study of HPN328 to assess the safety, tolerability and pharmacokinetics in patients with advanced cancers associated with expression of DLL3. HPN328 is being administered in fixed and step dosing to patients once weekly by intravenous infusion with dose escalation until a therapeutic dose level has been achieved. The primary outcome measure will be safety and tolerability, and to determine a dose for Phase 2.

About Harpoon Therapeutics

Harpoon Therapeutics is a clinical-stage immunotherapy 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. HPN217 targets BCMA and is in a Phase 1/2 trial for relapsed, refractory multiple myeloma. HPN328 targets DLL3 and is in a Phase 1/2 trial for small cell lung cancer and other DLL3-associated tumors. HPN536 targets mesothelin and is in a Phase 1/2a trial for cancers expressing mesothelin, initially focused on ovarian and pancreatic cancers. 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. The Company’s third proprietary technology platform, extended release TriTAC-XR, is designed to mitigate cytokine release syndrome. For additional information about Harpoon Therapeutics, please visit www.harpoontx.com.

Tecentriq^® (atezolizumab) is a registered trademark of F. Hoffmann La-Roche Ltd.

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 ”plan,” “target,” “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 development and advancement of Harpoon Therapeutics’ platforms and product candidates, including plans to initiate combination trials in multiple lines of therapy for patients with small cell lung cancer, progress, timing, scope, design and interim results of clinical trials, ability of TriTAC-XR T cell engager platform to mitigate toxicities, such as cytokine release syndrome, the candidate’s safety and tolerability profile, 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, unanticipated or greater than anticipated impacts or delays due to COVID-19, 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. 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’ annual report on Form 10-K for the year ended December 31, 2021 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:

Harpoon Therapeutics, Inc.
Georgia Erbez
Chief Financial Officer
650-443-7400
media@harpoontx.com

ICR Westwicke
Robert H. Uhl
Managing Director
858-356-5932
robert.uhl@westwicke.com