Press Release

Multiple Myeloma Partnership With Juno Therapeutics For Developing CAR T Cell Immunotherapy Against Multiple Novel Targets

EMERYVILLE, Calif. & NEW YORK & SEATTLE, Aug 4th, 2016 – Eureka Therapeutics, Inc. and Memorial Sloan Kettering Cancer Center(MSK) announced today an exclusive license agreement with Juno Therapeutics, Inc. (Nasdaq: JUNO) for a novel, fully-human binding domain targeting B-cell maturation antigen (BCMA), along with binding domains against two additional undisclosed multiple myeloma targets to be used for the potential development and commercialization of chimeric antigen receptor (CAR) cell therapies for patients with multiple myeloma. The binding domains were developed under a collaboration agreement between Eureka Therapeutics and MSK. The parties expect the BCMA CAR to enter human testing as early as 1H2017.

“We are optimistic that CAR T therapy can be an important component in treating patients with multiple myeloma, and we are pleased to bring additional fully-human binding domains against BCMA and other targets into our program,” said Hy Levitsky, M.D., Juno’s Chief Scientific Officer. “We believe that a multi-pronged approach may be necessary to treat this disease, and we will pursue more than one target against myeloma. The MSK and Eureka constructs are promising additions to our portfolio that will accelerate our efforts and provide additional opportunities to combat this disease.”

“We are pleased to work with Juno Therapeutics on developing CAR T therapies against multiple myeloma,” said Dr. Cheng Liu, President and Chief Executive Officer of Eureka Therapeutics. “Multiple myeloma is a devastating disease. For the past three years, we have been working with MSK to develop CAR T therapies against multiple myeloma, and we are delighted that Juno is able to use their broad expertise to bring these therapies to patients faster.”

MSK and Eureka Therapeutics are eligible to receive an undisclosed upfront payment, additional payments upon the achievement of undisclosed clinical, regulatory, and commercial milestones, and royalties on net sales.

About Eureka Therapeutics, Inc.

Eureka Therapeutics Inc. is a privately held biotechnology company, headquartered in the San Francisco Bay area, focused on developing first-in-class T cell immunotherapies for hematological malignancies and solid tumors. Its core technology platforms center around the discovery and engineering of fully human antibodies against intracellular targets via the MHCI complex. The company is developing a pipeline of novel cancer therapeutics targeting intracellular oncogenes.

www.eurekainc.com

About Memorial Sloan Kettering

Memorial Sloan Kettering Cancer Center is the world’s oldest and largest private institution devoted to prevention, patient care, research, and education in cancer. Its scientists and clinicians generate innovative approaches to better understand, diagnose, and treat cancer. Memorial Sloan Kettering specialists are leaders in biomedical research and in translating the latest research to advance the standard of cancer care worldwide.

www.mskcc.org

About Juno

Juno Therapeutics is building a fully integrated biopharmaceutical company focused on re-engaging the body’s immune system to revolutionize the treatment of cancer. Founded on the vision that the use of human cells as therapeutic entities will drive one of the next important phases in medicine, Juno is developing cell-based cancer immunotherapies based on chimeric antigen receptor and high-affinity T cell receptor technologies to genetically engineer T cells to recognize and kill cancer. Juno is developing multiple cell-based product candidates to treat a variety of B-cell malignancies as well as solid tumors. Several product candidates have shown compelling clinical responses in clinical trials in refractory leukemia and lymphoma conducted to date. Juno's long-term aim is to improve and leverage its cell-based platform to develop new product candidates that address a broader range of cancers and human diseases. Juno brings together innovative technologies from some of the world's leading research institutions, including the Fred Hutchinson Cancer Research Center, Memorial Sloan Kettering Cancer Center, Seattle Children's Research Institute, the University of California, San Francisco, and The National Cancer Institute. Juno Therapeutics has an exclusive license to the St. Jude Children’s Research Hospital patented technology for CD19 directed product candidates that use 4-1BB, which was developed by Dario Campana, Chihaya Imai, and St. Jude Children’s Research Hospital.

www.JunoTherapeutics.com

Juno Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, and Section 21E of the Securities Exchange Act of 1934, including statements regarding Juno’s business plans, the potential of T cell therapeutics, the potential of the BCMA binding domain and other human binders, clinical trial results and clinical trial plans, and planned activities and potential payments under the license agreement among Juno, Memorial Sloan Kettering, and Eureka Therapeutics. Forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from such forward-looking statements, and reported results should not be considered as an indication of future performance. These risks and uncertainties include, but are not limited to, risks associated with: the success, cost, and timing of Juno's product development activities and clinical trials; Juno's ability to obtain regulatory approval for and to commercialize its product candidates; Juno's ability to establish a commercially-viable manufacturing process and manufacturing infrastructure; regulatory requirements and regulatory developments; success of Juno's competitors with respect to competing treatments and technologies; Juno's dependence on third-party collaborators and other contractors in Juno's research and development activities, including for the conduct of clinical trials and the manufacture of Juno's product candidates; Juno's dependence on Celgene for the development and commercialization outside of North America and China of Juno’s CD19 product candidates and any other product candidates for which Celgene exercises an option; Juno’s dependence on JW Therapeutics (Shanghai) Co., Ltd, over which Juno does not exercise complete control, for the development and commercialization of product candidates in China; Juno's ability to obtain, maintain, or protect intellectual property rights related to its product candidates; amongst others. 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 Juno's business in general, see Juno's Annual Report on Form 10-Q filed with the Securities and Exchange Commission on May 10, 2016 and Juno’s other periodic reports filed with the Securities and Exchange Commission. These forward-looking statements speak only as of the date hereof. Juno disclaims any obligation to update these forward-looking statements.

Juno Investor Relations:
Nicole Keith
206-566-5521
nikki.keith@junotherapeutics.com

Juno Media:
Christopher Williams
206-566-5660
chris.williams@junotherapeutics.com

Eureka Therapeutics Inc.:
J.J. Liu, MBA
Head of Strategic Alliances
Eureka Therapeutics, Inc.
5858 Horton Street, Suite 362
Emeryville, CA 94608
510-654-7045
bd@eurekainc.com