Adaptive Biotechnologies Announces Completion of Series C and Series D Financing Rounds Through a $105 million Private Investment from Viking Global Investors

Original Founders of Adaptive

Investment fuels expansion of industry-leading immunosequencing research platform and diagnostic products for the treatment of cancer, autoimmune disorders, and infectious diseases

SEATTLE, WA, April 7, 2014 – Adaptive Biotechnologies announced today the completion of the Company’s Series C financing round and the completion of a newly created Series D round with a $105 million investment from Viking Global Investors. This investment will enable the Company to expand globally its preeminent immunosequencing research platform and downstream validated clinical diagnostic products. Viking’s investment contributed $5 million to close out the Series C round and $100 million in the Series D round, bringing the Company’s total capital raise to $120 million. Viking is the sole investor in Series D and will take an observer seat on Adaptive’s Board.

“We are honored to have been given the opportunity by our trusted partners at Viking to further grow our world class Company and state-of-the-art technology so we can better understand, diagnose, and monitor the immune response in patients living with diseases like cancer and autoimmune disorders,” said Chad Robins, CEO and Founder of Adaptive Biotechnologies. “We are excited to have our strategic vision of immunosequencing across disease states be validated by a large capital investment from Viking. The creation of data to influence clinical care represents the next wave of opportunity, and these proceeds will allow us to build our organization with top talent in all key areas from research to sales and to further commercialize our platforms and applications.”

Initially, funds will be allocated to the expansion of the Company’s research platform, immunoSEQTM, via the launch of a Research Use Only kit in the third quarter of 2014. The distribution of a kit that incorporates the critical standardization and quality control measures used in Adaptive’s CLIA certified lab will enable Adaptive’s customers to perform immunosequencing in-house. Additionally, funds will be used to fuel the expansion of the company’s first diagnostic product, clonoSEQTM, for monitoring relapse in patients with certain blood cancers. Resources will also be deployed to validate and launch an assay called quanTILfyTM that interrogates Tumor Infiltrating Lymphocytes in solid tumors for prognosis and as a potential predictive biomarker of response to treatment with cancer immunotherapies.

About Adaptive Biotechnologies:

Adaptive Biotechnologies Corporation (“Adaptive” or the “Company”) is a pioneer in immunosequencing diagnostics, with a focus in oncology. The Company leverages advances in next generation sequencing (“NGS”) to profile T-Cell and B-Cell Receptors (“TCRs” and “BCRs”). This patented breakthrough enables in-depth characterization of the immune system, which is the primary defense against cancer. By incorporating immunosequencing into clinical care, Adaptive can enhance the diagnosis, prognosis, and monitoring of cancer patients. The Company’s first clinical application, clonoSEQTM, is for monitoring Minimal Residual Disease (“MRD”) in blood-based cancers. The Company recently launched clonoSEQTM as a CLIA certified Laboratory Developed Test (“LDT”) in the second quarter of 2013. Improving the ability to accurately detect and track residual disease at a molecular level affords clinicians the potential to detect relapse earlier and improve patient care. Adaptive is currently validating additional oncology diagnostics to quantify the presence and clonality of Tumor Infiltrating Lymphocytes (“TIL”) and to create a reliable measure of “immunocompetency” to predict or monitor response to cancer treatments that directly alter the host immune system. Adaptive incubates and validates potential clinical products by offering fee-for-service access to its proprietary immune profiling sequencing technology under the brand name immunoSEQTM.