Updated Clinical Results and New Translational Research Data for Daiichi Sankyo's ADCs U3-1402 and DS-1062 to be Presented at the 2019 World Conference on Lung Cancer

-- Late-breaking U3-1402 and DS-1062 results in advanced or metastatic non-small cell lung cancer (NSCLC) to be presented

-- New findings on biomarker expression and genomic alterations also will be reported alongside patient response data

-- Oral presentations reflect translational research-driven approach to advance clinical development of Daiichi Sankyo's ADCs for precision treatment of NSCLC

MUNICH and BASKING RIDGE, New Jersey, Aug. 22, 2019 /PRNewswire/ -- Daiichi Sankyo Company, Limited (hereafter, Daiichi Sankyo) today announced that updated results and new translational research data from two phase 1 studies evaluating investigational antibody drug conjugates (ADCs) U3-1402 and DS-1062 in patients with advanced or metastatic non-small cell lung cancer (NSCLC) will be presented at the 2019 IASLC World Conference on Lung Cancer (WCLC19), to be held September 7-10, 2019 in Barcelona, Spain.

The oral presentations will feature updated safety and efficacy results for U3-1402, a potential first-in-class HER3 targeting ADC being evaluated in patients with EGFR mutated metastatic NSCLC that has become resistant to TKI therapy, and for DS-1062, a TROP2 targeting ADC being evaluated in patients with advanced NSCLC who have progressed on standard treatments or for whom no standard treatment is available. Translational research findings from both studies, including biomarker expression and genomic alterations, will be presented alongside patient response data.

"As we continue to report our progress in clinical development of U3-1402 and DS-1062 in NSCLC, we also will begin to showcase some of the advanced translational research being conducted in the trials," said Antoine Yver, MD, MSc, EVP and Global Head, Oncology Research and Development, Daiichi Sankyo. "We are using cutting-edge tools to assess biomarker expression, genomic alterations and tumor burden; analyzing their relationships to treatment response; and pushing the boundaries of current science to fully leverage the potential of our ADCs in a precision medicine approach."

Both U3-1402 and DS-1062 are designed using Daiichi Sankyo's proprietary DXd ADC technology, which consists of a monoclonal antibody attached by a tetrapeptide-based linker to a novel topoisomerase I inhibitor payload. Each ADC is constructed to target and deliver chemotherapy inside cancer cells that express a specific cell surface antigen, and each has a customized drug to antibody ratio (DAR) designed to attain the intended safety and efficacy for the target under investigation.

U3-1402 and DS-1062 are Daiichi Sankyo's second and third ADCs in clinical development for NSCLC, following [fam-] trastuzumab deruxtecan (DS-8201), which is being co-developed and co-commercialized globally in collaboration with AstraZeneca. U3-1402 also is being evaluated in a phase 1/2 trial in patients with HER3 positive metastatic breast cancer.

Following are details of the Daiichi Sankyo presentations at WCLC:

• "Preliminary Phase 1 Results from U3-1402-a Novel HER3 Targeted Antibody Drug Conjugate - in EGFR TKI resistant, EGFR mutant NSCLC" (Abstract #1720. Mini Oral Session MA21: Non EGFR/MET Targeted Therapies. Tuesday, September 10, 2019. 14:30 - 16:00 CEST)

• "First-in-Human Phase 1 Study of DS-1062a (TROP2 Antibody Drug Conjugate) in Patients with Advanced Non-Small Cell Lung Cancer" (Abstract #3854. Mini Oral Session MA25: Precision Medicine in Advanced NSCLC. Tuesday, September 10, 2019. 14:30 - 16:00 CEST)

U3-1402, DS-1062 and DS-8201 are investigational agents that have not been approved for any indication in any country. Safety and efficacy have not been established.

About Daiichi Sankyo Cancer Enterprise
The mission of Daiichi Sankyo Cancer Enterprise is to leverage our world-class, innovative science and push beyond traditional thinking to create meaningful treatments for patients with cancer. We are dedicated to transforming science into value for patients, and this sense of obligation informs everything we do. Anchored by three pillars including our investigational Antibody Drug Conjugate Franchise, Acute Myeloid Leukemia Franchise and Breakthrough Science, we aim to deliver seven distinct new molecular entities over eight years during 2018 to 2025. Our powerful research engines include two laboratories for biologic/immuno-oncology and small molecules in Japan, and Plexxikon Inc., our small molecule structure-guided R&D center in Berkeley, CA. For more information, please visit: www.DSCancerEnterprise.com.

About Daiichi Sankyo
Daiichi Sankyo Group is dedicated to the creation and supply of innovative pharmaceutical therapies to improve standards of care and address diversified, unmet medical needs of people globally by leveraging our world-class science and technology. With more than 100 years of scientific expertise and a presence in more than 20 countries, Daiichi Sankyo and its 15,000 employees around the world draw upon a rich legacy of innovation and a robust pipeline of promising new medicines to help people. In addition to a strong portfolio of medicines for cardiovascular diseases, under the Group's 2025 Vision to become a "Global Pharma Innovator with Competitive Advantage in Oncology," Daiichi Sankyo is primarily focused on providing novel therapies in oncology, as well as other research areas centered around rare diseases and immune disorders. For more information, please visit: www.daiichisankyo.com.

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Prepared August 2019Job Code: ONP/19/0051