Harpoon Therapeutics, a biotechnology company developing novel T-cell recruiting biologic therapies for the treatment of cancer, today announced the completion of a $45M Series B financing, which included Arix Bioscience, New Leaf Venture Partners and Taiho Ventures, who are all new investors in the company, and existing investor MPM Capital. The financing was co-led by Arix Bioscience and New Leaf Venture Partners. Mark Chin, Investment Manager at Arix, and Ron Hunt, Managing Director at New Leaf, will join the Harpoon Therapeutics board of directors. In addition, Sakae Asanuma, President of Taiho Ventures, will join the board of directors in an observer capacity.

Proceeds from the financing will be used to advance Harpoon Therapeutics' novel, proprietary, tri-specific T-cell activating construct (TriTAC) immuno-oncology platform, including moving two lead programs into clinical trials and expanding the product pipeline through discovery and partnering initiatives. In addition, the company is increasing its commitment to developing additional therapeutic platforms including those that become activated by proteases present in the tumor microenvironment.

"We are delighted to have top-tier investors supporting the Series B financing, and welcome new investors as Harpoon shareholders," said Jerry McMahon, PhD, President and Chief Executive Officer of Harpoon Therapeutics. "This investment is a clear validation of Harpoon's TriTAC™ platform, which offers a new way to unleash the targeted cell-killing properties of a patient's own immune system with a potential best-in-class T-cell engager platform."

"We have been strong advocates of Harpoon Therapeutics from inception, and are pleased to participate in this latest round of financing, which provides capital to transition Harpoon to a clinical-stage company as well as to advance critical discovery and research efforts," said Luke Evnin, PhD, Co-Founder and Chairman of Harpoon, and Founder and Managing Director at MPM Capital.

"Harpoon Therapeutics has a novel, T-cell engager platform which we believe will be instrumental to the discovery and development of important new therapeutics in oncology," said Mark Chin, Investment Manager at Arix Bioscience, a global healthcare and life science company supporting medical innovation. "Coupled with its scientific expertise and strong management team, Harpoon is well-positioned to play a leading role in the immuno-oncology field."

"New Leaf looks for experienced management teams, strong science and high-impact clinical benefit potential, all of which Harpoon Therapeutics significantly offers," said Ron Hunt, Managing Director at New Leaf Venture Partners, a leader in healthcare investing. "We are pleased to be co-leading this Harpoon investment with Arix and look forward to helping the company make important strides as it continues to advance its pipeline."

Harpoon's first clinical candidate, HPN424, is a prostate-specific membrane antigen (PSMA)-targeting TriTAC™. HPN424 is in development for the treatment of metastatic prostate cancer and is expected to enter Phase 1 clinical trials in 2018. The company anticipates identifying and moving into development additional clinical candidates within the next year.

About Harpoon Therapeutics -- Harpoon Therapeutics is an immuno-oncology company founded by Patrick Baeuerle, PhD, a pioneer in the development of T-cell engaging therapies, and MPM Capital. The company is focused on the discovery and development of novel T-cell engaging biologics for the treatment of cancer and other diseases. Harpoon Therapeutics created a novel antibody-based drug discovery platform called TriTAC (tri-specific T-cell activating construct) to unleash the targeted cell-killing properties of a patient's own immune system through T-cell activation. This approach has been optimized to penetrate tissues and extend serum exposure, and has the potential to address a broad range of cancers, including solid tumors, and immunologic diseases. HPN424, a prostate-specific membrane antigen (PSMA)-targeting TriTAC biologic, is in development for the treatment of prostate cancer and is expected to enter a clinical trial in 2018. For more information, please visit www.harpoontx.com.

About MPM Capital -- MPM Capital is an early-stage life sciences venture firm founding and investing in companies that seek to cure major diseases by translating scientific innovations into positive clinical outcomes. MPM's portfolio of companies aims to revolutionize the face of medicine across multiple areas including cancer, diabetes, obesity, pain, eHealth and more. With its experienced and dedicated team of operating executives and medical and scientific advisory board, MPM is powering novel medical breakthroughs that transform patients' lives. MPM is currently investing from two funds ' the BV2014 and UBS Oncology Impact Fund. For further information, please visit www.mpmcapital.com.

About Arix Bioscience plc

Arix Bioscience plc is a global healthcare and life science company supporting medical innovation. Headquartered in London and with an office in New York, Arix Bioscience sources, finances and builds world class healthcare and life science businesses addressing medical innovation at all stages of development. Operations are supported by privileged access to breakthrough academic science and strategic relationships with leading research accelerators and global pharmaceutical companies. Arix Bioscience plc is listed on the Main Market of the London Stock Exchange. For further information, please visit www.arixbioscience.com

About NLV Partners

New Leaf Venture Partners is a leader in healthcare technology venture investing. Our investment professionals bring a unique blend of technical, clinical and operational experience to our investments, working closely with our entrepreneurs and management teams to help build successful companies. New Leaf Ventures invests in both public and private biopharmaceutical companies as well as healthcare-related information technology companies. New Leaf currently manages over $1 billion in assets. This includes NLV's funds, New Leaf Ventures I, L.P., New Leaf Ventures II, L.P., New Leaf Ventures III, L.P. and New Leaf Growth Fund I, L.P. New Leaf was formed in 2005 as the healthcare spinoff from the Sprout Group, one of the oldest U.S. venture capital funds. For more information please visit www.nlvpartners.com.

About Taiho Ventures, LLC

Taiho Ventures, LLC is the strategic corporate venture capital arm of Taiho Pharmaceutical Co. Ltd., a Japanese specialty pharma focusing on oncology, allergy and immunology, and urology. Taiho Ventures is a newly-established strategic investor looking at early stage preclinical oncology companies as well as platform technology companies for our core therapeutic areas. Taiho Ventures will review the wide variety of modalities for both biologics and small molecules mainly in US and European countries. The company will also consider the option-type of investments and spin-outs, in addition to the pure equity investments. For more information about Taiho Ventures, please visit www.taihoventures.com.