Gilead Sciences, Inc. (Nasdaq: GILD) and Gritstone Oncology, Inc. (Nasdaq: GRTS), a clinical-stage biotechnology company developing next generation cancer and infectious disease immunotherapies, today announced that the companies have entered into a collaboration, option and license agreement to research and develop a vaccine-based immunotherapy as part of Gilead?s efforts to find a curative treatment for human immunodeficiency virus (HIV) infection. Gilead and Gritstone will develop an HIV-specific therapeutic vaccine using Gritstone?s proprietary prime-boost vaccine platform, comprised of self-amplifying mRNA (SAM) and adenoviral vectors, with antigens developed by Gilead. ?While HIV treatment has advanced dramatically over the past three decades, people living with HIV still face a lifetime of therapy,? said?Diana Brainard, MD, Senior Vice President, Virology Therapeutic Area,?Gilead Sciences. ?Curing HIV remains the ultimate aspiration for Gilead?s HIV research and development efforts. Gritstone?s vaccine technology has the potential to educate the immune system to specifically recognize and destroy HIV-infected cells by leveraging SAM and adenoviral vectors. This, along with our other partnerships and internal programs, reflects Gilead?s commitment to continuing innovation to discover a cure for HIV and bring about an end to the HIV epidemic.? ?We are excited to be partnering with Gilead, a company that has decades long experience improving care for people living with HIV, to advance a novel immunotherapy using our proprietary platform for the treatment of HIV infection,? said Andrew Allen, MD, PhD, Co-Founder, President and Chief Executive Officer of Gritstone. ?It is well-established that CD8+ T cells are critical for the elimination of virally infected cells, and we have built a highly differentiated vaccine platform that has been shown to generate large numbers of antigen-specific T cells, including CD8+ T cells, even in advanced and immunocompromised cancer patients. On the heels of our recent COVID-19 program initiation in partnership with the NIH, this program adds to our growing infectious disease pipeline supported by collaborations with leading biopharma and renowned institutions.? ?Delivery of viral antigens in potent vaccine vectors to elicit a strong immune response is a cornerstone of successful infectious disease vaccines,? said Karin Jooss, PhD, Executive Vice President of Research and Chief Scientific Officer of Gritstone. ?Our preclinical work at Gritstone developing our powerful prime-boost vaccine technology utilized simian immunodeficiency virus (SIV) derived antigens as model antigens, which are very similar to HIV-1. The resulting strong, durable and broad anti-SIV CD8+ T cell responses and T cell memory data captured the attention of Gilead?s virology team. We jointly performed further experiments that generated additional compelling data, which was also complemented by our exciting clinical data with neoantigens in cancer patients. We are delighted to now advance our partnership and product candidates for the treatment of patients with HIV infection.? Terms of the Agreement Under the terms of the agreement, Gilead will make a $60 million payment at closing, consisting of a $30 million upfront cash payment and a $30 million equity investment at a premium. Gilead will be responsible for conducting a Phase 1 study for the HIV-specific therapeutic vaccine and holds an exclusive option under the collaboration to obtain an exclusive license to develop and commercialize the HIV-specific therapeutic vaccine beyond Phase 1. Gritstone is also eligible to receive up to an additional $725 million if the option is exercised and if certain clinical, regulatory and commercial milestones are achieved, as well as mid single-digit to low double-digit tiered royalties on net sales upon commercialization. Locust Walk served as transaction advisor to Gritstone. About Gritstone Oncology Gritstone Oncology (Nasdaq: GRTS), a clinical-stage biotechnology company, is developing the next generation of immunotherapies against multiple cancer types and infectious diseases. Gritstone develops its products by leveraging two key pillars?first, a proprietary machine learning-based platform, Gritstone EDGE^TM, which is designed to predict antigens that are presented on the surface of cells, such as tumor or virally-infected cells, that can be seen by the immune system; and second, the ability to develop and manufacture potent immunotherapies utilizing these antigens to potentially drive the patient?s immune system to specifically attack and destroy disease-causing cells. The company?s lead oncology programs include an individualized neoantigen-based immunotherapy, GRANITE, and an ?off the shelf? shared neoantigen-based immunotherapy, SLATE, which are being evaluated in clinical studies. The company also has a bispecific antibody (BiSAb) program for solid tumors in lead optimization. Within its infectious disease pipeline, Gritstone is advancing CORAL, a COVID-19 program to develop a second-generation vaccine with support from departments within the National Institutes of Health (NIH) and the Bill & Melinda Gates Foundation and a license agreement with La Jolla Institute for Immunology. Additionally, the company has a global collaboration for the development of a therapeutic HIV vaccine with Gilead Sciences. For more information, please visit gritstoneoncology.com. About Gilead Sciences Gilead Sciences, Inc.?is a research-based biopharmaceutical company that discovers, develops and commercializes innovative medicines in areas of unmet medical need. The company strives to transform and simplify care for people with life-threatening illnesses around the world. Gilead has operations in more than 35 countries worldwide, with headquarters in?Foster City, California. For more information on Gilead Sciences, please visit the company?s website at?www.gilead.com. Gritstone Forward-Looking Statements This press release contains forward-looking statements, including, but not limited to, statements related to the potential of Gritstone?s therapeutic programs; the advancements in the Company?s ongoing clinical trials; the timing of data announcements related to ongoing clinical trials and the initiation of future clinical trials. Such forward-looking statements involve substantial risks and uncertainties that could cause Gritstone?s research and clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the drug development process, including Gritstone?s programs? early stage of development, the process of designing and conducting preclinical and clinical trials, the regulatory approval processes, the timing of regulatory filings, the challenges associated with manufacturing drug products, Gritstone?s ability to successfully establish, protect and defend its intellectual property and other matters that could affect the sufficiency of existing cash to fund operations. Gritstone undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the company in general, see Gritstone?s most recent Quarterly Report on Form 10-Q filed on November 5, 2020 and any current and periodic reports filed with the Securities and Exchange Commission. Gilead Forward-Looking Statements This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including the ability of the parties to meet potential milestones in the estimated timelines or at all and the risk that the parties may not realize the expected benefits of this collaboration. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in Gilead?s Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, as filed with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation to update any such forward-looking statements.