— Phase 2 study will Examine the Effect of Mavrilimumab on the Clinical Profile of Yescarta —

SANTA MONICA, CA, USA & HAMILTON, Bermuda I December 11, 2019 I Kite, a Gilead Company (Nasdaq: GILD), and Kiniksa Pharmaceuticals, Ltd. (Nasdaq: KNSA) (“Kiniksa”) announced today that the companies have entered into a clinical collaboration to conduct a Phase 2, multicenter study of mavrilimumab, an investigational fully human monoclonal antibody that targets granulocyte macrophage colony stimulating factor receptor alpha (GM-CSFRα), in combination with Yescarta® (axicabtagene ciloleucel) in patients with relapsed or refractory large B-cell lymphoma. The objective of the study is to determine the effect of mavrilimumab on the safety of Yescarta. Kite will be the sponsor of this study and will be responsible for its conduct.

“We were excited to present data from several abstracts at the recent ASH meeting that build upon our understanding of the efficacy and safety profile of Yescarta and we are committed to the exploration of new approaches and treatment combinations that further optimize outcomes for patients,” said Christi Shaw, Chief Executive Officer of Kite. “We look forward to working with Kiniksa to learn more about the potential impact of GM-CSFRα inhibition with mavrilimumab.”

“The clinical collaboration with Kite furthers Kiniksa’s goal to develop life-changing medicines for patients with significant unmet medical need,” said Sanj K. Patel, Chief Executive Officer and Chairman of the Board of Kiniksa. “We believe the potential for GM-CSFRα inhibition to advance the clinical profile for CAR T cell therapy speaks to the potential broad utility of mavrilimumab.”

Treatment related induction of GM-CSF has been identified through clinical, translational and preclinical studies as a potential key signal associated with side effects of chimeric antigen receptor T (CAR T) cell therapy. Preclinical evidence shows the potential for interruption of GM-CSF signaling to disrupt CAR T cell mediated inflammation without disrupting anti-tumor efficacy.

Yescarta was the first CAR T cell therapy to be approved by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL) not otherwise specified, primary mediastinal large B-cell lymphoma, and high grade B-cell lymphoma and DLBCL arising from follicular lymphoma. Yescarta is not indicated for the treatment of patients with primary central nervous system lymphoma. The Yescarta U.S. Prescribing Information has a BOXED WARNING for the risks of cytokine release syndrome and neurologic toxicities; see below for Important Safety Information.

Mavrilimumab, alone or in combination with other therapies such as Yescarta, is investigational and has not been approved by the FDA or any regulatory authority for any uses. Efficacy and safety have not been established.

About Mavrilimumab

Mavrilimumab is an investigational fully-human monoclonal antibody that is designed to antagonize GM-CSF signaling by binding to the alpha subunit of the GM-CSF receptor. Kiniksa is developing mavrilimumab for the potential treatment of giant cell arteritis (GCA), a chronic inflammatory disease of medium to large arteries.

About Kite

Kite, a Gilead Company, is a biopharmaceutical company based in Santa Monica, California. Kite is engaged in the development of innovative cancer immunotherapies. The company is focused on chimeric antigen receptor and T cell receptor engineered cell therapies. For more information on Kite, please visit www.kitepharma.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.

About Kiniksa

Kiniksa is a biopharmaceutical company focused on discovering, acquiring, developing and commercializing therapeutic medicines for patients suffering from debilitating diseases with significant unmet medical need. Kiniksa has a pipeline of product candidates across various stages of development, focused on autoinflammatory and autoimmune conditions. For more information, please visit www.kiniksa.com.

SOURCE: Kite