Daiichi Sankyo's ADC engine grows fast but leans on Enhertu

Daiichi Sankyo has become an oncology company built on one platform. Its DXd antibody-drug conjugates, led by Enhertu and Datroway, drove first-quarter revenue up 21.1% to JPY 574.7 billion. The company's five-year plan targets more than JPY 3 trillion of revenue in fiscal 2030 and a place among the top five oncology companies by 2035.

The technology

The DXd platform links an antibody to a topoisomerase I inhibitor payload. Enhertu targets HER2 and is co-developed with AstraZeneca. In 2026 it won two US early breast cancer approvals and positive first-line data in HER2-mutant lung cancer, where DESTINY-Lung04 extended median progression-free survival to 14.3 months from 8.3 months. Datroway targets TROP2 and was approved in the US for first-line triple-negative breast cancer on survival data.

Behind them are I-DXd (B7-H3, partnered with Merck), raludotatug deruxtecan in ovarian cancer and newer programs such as the CD25-directed DS1025, all listed in the ESMO 2026 announcement. Daiichi also plans combination work, including a Datroway and ivonescimab collaboration with AstraZeneca and Summit Therapeutics. Enhertu carries boxed warnings for interstitial lung disease and embryo-fetal toxicity, and the label now covers earlier, curative-intent disease where tolerability weighs more heavily.

The odds

The platform has a strong record in breast cancer. Lung is harder. The I-DXd US filing in small cell lung cancer was withdrawn on September 25 after the FDA said phase 2 data did not support accelerated approval, and DESTINY-Lung04 showed no overall survival benefit at 46.9% maturity.

For phase III programs such as IDeate-Lung02, the BIO/Informa/QLS 2011-2020 base rate is 57.8% from phase III to filing and 90.6% from filing to approval. ADCs with established payloads and targets probably beat that average, but the I-DXd experience shows that response-rate data can fall short with the FDA.

The money

Daiichi is profitable. Cash and cash equivalents were JPY 637.9 billion at June 30, and non-current bonds and borrowings were JPY 500.0 billion after a JPY 200 billion issue in the quarter. The company also transferred 30% of its consumer health unit to Suntory on July 1 for JPY 73.95 billion, with further transfers of 40% in June 2027 and the remaining 30% in June 2029. The five-year plan also calls for more than JPY 200 billion of cost and profit improvements by 2030. Full-year guidance calls for JPY 2.34 trillion of revenue and JPY 320.0 billion of operating profit.

The risks

Concentration comes first. Enhertu was JPY 239.8 billion of first-quarter revenue, about 42%, and it is co-developed and co-sold with AstraZeneca.

Manufacturing commitments are the second. Daiichi booked a JPY 75.7 billion CMO provision after demand forecasts fell, and said it has made no provision for the medium- and long-term gap against minimum purchase obligations. Accounting quality is the third: the company corrected an SG&A aggregation error in its fiscal 2025 results.

Our read

Daiichi's breast cancer franchise is working, and the 2026 approvals widen it into earlier disease. The plan to reach JPY 3 trillion depends on lung cancer and newer ADCs, where 2026 brought both a win and a setback.

The supply loss is the best guide to the risk. When trials narrow populations, Daiichi pays twice: in lost revenue and in contract commitments. The ESMO congress from October 23 to 27 and the AVANZAR readout in the second half of calendar 2026 are the next tests.