Company Announcements

• Late-breaking data from IDeate-Lung01 phase 2 trial demonstrate potential of ifinatamab deruxtecan to become first-in-class B7-H3 directed ADC for pretreated extensive-stage small cell lung cancer
• Investor briefing to discuss WCLC data and ifinatamab deruxtecan clinical development program

TOKYO & BASKING RIDGE, N.J.--(BUSINESS WIRE)--Aug. 14, 2025-- Daiichi Sankyo (TSE: 4568) will present new clinical research across its DXd antibody drug conjugate (ADC) portfolio in lung cancer at the IASLC 2025 World Conference on Lung Cancer hosted by the International Association for the Study of Lung Cancer (#WCLC25).

Data at WCLC will showcase the company’s progress towards creating new standards of care for patients with lung cancer, including a late-breaking oral presentation featuring the primary analysis from the dose optimization and dose expansion parts of the IDeate-Lung01 phase 2 trial (OA06.03) of ifinatamab deruxtecan (I-DXd) in patients with pretreated extensive-stage small cell lung cancer (ES-SCLC). Interim data from the dose optimization part of the trial was previously presented at 2024 WCLC.

“The late-breaking data at WCLC continues to demonstrate the potential of ifinatamab deruxtecan to become a first-in-class B7-H3 directed antibody drug conjugate for patients with pretreated extensive-stage small cell lung cancer, where treatment options following platinum-based chemotherapies are limited,” said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. “These data along with other important updates across our portfolio continue to demonstrate how our DXd antibody drug conjugate technology is being leveraged to create new medicines for patients with cancer.”

Additional data updates at WCLC include an oral presentation featuring a retrospective analysis of the intracranial efficacy of DATROWAY^® (datopotamab deruxtecan) or docetaxel in patients with non-small cell lung cancer (NSCLC) and baseline brain metastases in the TROPION-Lung01 phase 3 trial (0A10.01), and a poster presentation of the final results of the DESTINY-Lung05 phase 2 trial (P2.10.12) of ENHERTU^® (trastuzumab deruxtecan) in patients from China with previously treated HER2 mutant NSCLC.

Trials-in-Progress Across DXd ADC Portfolio

Several trials-in-progress poster presentations at WCLC further highlight the Daiichi Sankyo R&D strategy of continuing to expand the DXd ADC portfolio to address a broad spectrum of unmet needs for patients with lung cancer, including the DESTINY-Lung06 phase 3 trial evaluating the efficacy and safety of ENHERTU plus pembrolizumab versus platinum-based chemotherapy plus pembrolizumab as a first-line treatment strategy for patients with HER2 overexpressing, PD-L1 TPS <50% metastatic NSCLC.

Other early phase trials evaluating additional treatment strategies in lung cancer include the KEYMAKER-U01 substudy 01G phase 2 trial evaluating patritumab deruxtecan (HER3-DXd) in combination with pembrolizumab with or without platinum chemotherapy in patients with previously untreated stage 4 NSCLC, and a phase 1b/2 trial evaluating ifinatamab deruxtecan and gocatamig, a DLL3 targeted T-cell engager, in patients with relapsed or refractory ES-SCLC will be highlighted.

Investor Briefing Following WCLC

Daiichi Sankyo will hold a virtual conference call for investors on Wednesday, September 17, 2025 from 7:00 to 8:15 pm EDT / Thursday, September 18 from 8:00 to 9:15 am JST. Executives from Daiichi Sankyo will provide an overview of the late-breaking WCLC data and clinical development plan for ifinatamab deruxtecan.

WCLC Presentation Overview

About the ADC Portfolio of Daiichi Sankyo

The Daiichi Sankyo ADC portfolio consists of seven ADCs in clinical development crafted from two distinct ADC technology platforms discovered in-house by Daiichi Sankyo.

The ADC platform furthest in clinical development is Daiichi Sankyo’s DXd ADC Technology where each ADC consists of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers. The DXd ADC portfolio currently consists of ENHERTU, a HER2 directed ADC, and DATROWAY, a TROP2 directed ADC, which are being jointly developed and commercialized globally with AstraZeneca. Patritumab deruxtecan (HER3-DXd), a HER3 directed ADC, ifinatamab deruxtecan (I-DXd), a B7-H3 directed ADC, and raludotatug deruxtecan (R-DXd), a CDH6 directed ADC, are being jointly developed and commercialized globally with Merck & Co., Inc, Rahway, NJ, USA. DS-3939, a TA-MUC1 directed ADC, is being developed by Daiichi Sankyo.

The second Daiichi Sankyo ADC platform consists of a monoclonal antibody attached to a modified pyrrolobenzodiazepine (PBD) payload. DS-9606, a CLDN6 directed PBD ADC, is the first of several planned ADCs in clinical development utilizing this platform. Ifinatamab deruxtecan, patritumab deruxtecan, raludotatug deruxtecan, DS-3939 and DS-9606 are investigational medicines that have not been approved for any indication in any country. Safety and efficacy have not been established.

About Daiichi Sankyo

Daiichi Sankyo is an innovative global healthcare company contributing to the sustainable development of society that discovers, develops and delivers new standards of care to enrich the quality of life around the world. With more than 120 years of experience, Daiichi Sankyo leverages its world-class science and technology to create new modalities and innovative medicines for people with cancer, cardiovascular and other diseases with high unmet medical needs. For more information, please visit www.daiichisankyo.com.

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Media Contacts:

Global/US Media:
Jennifer Brennan
Daiichi Sankyo
jennifer.brennan@daiichisankyo.com
+ 1 908 900 3183 (mobile)

Japan:
Daiichi Sankyo Co., Ltd.
DS-PR_jp@daiichisankyo.com

Investor Relations Contact:
DaiichiSankyoIR_jp@daiichisankyo.com

Source: Daiichi Sankyo