Oct 22, 2026

New data from six landmark trials reinforce practice-changing results of Enhertu and Datroway across a broad spectrum of patients in breast and lung cancer Additional analyses from two trials of raludotatug deruxtecan in ovarian cancer demonstrate emerging potential in gynecological cancers Tokyo – (October 22, 2026) – Daiichi Sankyo (TSE: 4568) will present new clinical research across its oncology portfolio with more than 30 abstracts, including four late breaking presentations, in multiple cancers at the 2026 European Society for Medical Oncology (#ESMO26) Congress. New data from six landmark trials demonstrate the company’s progress toward advancing new standards of care for patients in breast and lung cancer, including the DESTINY-Breast05 (539RO), DESTINY-Breast06 (4279P), DESTINY-Breast09 (LBA49), DESTINY-Breast11 (543RO) and DESTINY-Lung04 (LBA74) phase 3 trials of Enhertu® (trastuzumab deruxtecan) and the TROPION-Breast02 (LBA96) phase 3 trial of Datroway® (datopotamab deruxtecan). Additional data at ESMO also will spotlight the company’s commitment to advancing research for patients with advanced ovarian cancer across lines of therapy. An updated analysis, including progression-free survival and duration of response, will be presented from the REJOICE-Ovarian01 (1331P) phase 2/3 trial evaluating raludotatug deruxtecan (R-DXd) in patients with platinum-resistant ovarian cancer. A mini oral presentation will highlight preliminary findings from the REJOICE-Ovarian02 (1247RO) phase 1b/2 trial evaluating raludotatug deruxtecan in combination with bevacizumab in patients with platinum-resistant ovarian cancer. “The promising data for raludotatug deruxtecan in ovarian cancer and the robust scientific innovation demonstrated across our pipeline reflects our progress in advancing research for patients across multiple types of cancer,” said John Tsai, MD, Global Head, R&D, Daiichi Sankyo. “Daiichi Sankyo continues to draw from its scientific and technological expertise to turn science into new medicines that can change the standard of care.” Data Demonstrate Benefit of DXd ADCs in Patients with Brain Metastases Research updates highlighting the impact of DXd ADCs in patients with brain metastases include late-breaking rapid oral and proffered paper presentations from the DESTINY-Breast09(LBA49) phase 3 trial evaluating Enhertu in combination with pertuzumab as a first-line treatment for patients with HER2 positive metastatic breast cancer and the TROPION-Breast02(LBA96) phase 3 trial evaluating Datroway as a first-line treatment for patients with locally recurrent inoperable or metastatic triple negative breast cancer for whom immunotherapy was not an option. Final overall survival results of the TUXEDO-3(690O)phase 2 trial of patritumab deruxtecan (HER3-DXd) in patients with active brain metastases from metastatic breast cancer, advanced non-small cell lung cancer (NSCLC) or leptomeningeal disease from any solid tumor will be presented as a proffered paper. New Data and Trials-in-Progress Presentations Across DXd ADC Portfolio Additional data highlighting new research across the DXd ADC portfolio include oral and poster presentations, including final results of the TALENT(LBA23) phase 2 trial of Enhertu alone or in combination with anastrozole, or in sequence with chemotherapy, as neoadjuvant treatment for patients with HR positive, HER2 low early stage breast cancer. New data in NSCLC include the NeoCOAST-2(4244RO) phase 2 trial reporting event-free survival results, as well as findings on the association of ctDNA clearance with clinical outcomes in patients with resectable, early stage NSCLC treated with a combination of Datroway plus durvalumab and chemotherapy, and a retrospective analysis evaluating mechanisms of insensitivity to the Datroway payload in subgroups of patients with advanced NSCLC in the TROPION-Lung01(4451P) phase 3 trial. Updated findings from the EPOC2003(2888P) phase 2 trial evaluating neoadjuvant chemotherapy in combination with Enhertu in patients with HER2 positive gastric cancer: results from ESPERANZA(1014P), an external comparator study evaluating Enhertu versus real-world standard of care as a second line or later treatment for patients with HER2 IHC 3+ solid tumors; and, the primary analysis evaluating patritumab deruxtecan monotherapy in patients with melanoma in the HERTHENA-PanTumor01(2073RO) phase 2 trial also will be presented. Trials-in-progress poster presentations include the DESTINY-Breast Guide (1795TiP) prospective and interventional trial evaluating first-line treatment with Enhertu plus pertuzumab followed by palbociclib, endocrine therapy and dual HER2 blockade (trastuzumab plus pertuzumab), as well as retreatment with Enhertu following progression on maintenance therapy (palbociclib, endocrine therapy and trastuzumab plus pertuzumab) in previously untreated patients with HER2 positive advanced or metastatic breast cancer and the TROY (1335TiP) phase 2 trial evaluating Enhertu in patients with recurrent ovarian cancer with disease progression on prior PARP inhibitor therapy. An overview of late-breaking, clinical data and trials-in-progress presentations from the ADC portfolio of Daiichi Sankyo includes:   Presentation Title Author Abstract Presentation (CEST) LBAs Final results of TALENT: a neoadjuvant trial of T-DXd with or without anastrozole, or in sequence with chemotherapy for HER2-low, HR+ early-stage breast cancer S. Hurvitz LBA23 Proffered Paper Presentation Friday, October 23 1:30 pm – 3:00 pm First-line datopotamab deruxtecan (Dato-DXd) vs. chemotherapy in patients with locally recurrent inoperable or metastatic triple negative breast cancer for whom immunotherapy was not an option: exploratory analysis of patients with brain metastases in TROPION-Breast02 R. Dent LBA96 Proffered Paper Presentation Saturday, October 24 8:30 am – 10:00 am First-line trastuzumab deruxtecan (T-DXd) in patients with HER2-mutant NSCLC: patient-reported outcomes from DESTINY-Lung04 S. Novello LBA74 Rapid Oral Presentation Saturday, October 24 8:30 am – 10:00 am DESTINY-Breast09 analysis of trastuzumab deruxtecan (T-DXd) + pertuzumab vs. taxane + trastuzumab + pertuzumab for patients with HER2+ advanced/metastatic breast cancer and baseline brain metastases C. Saura LBA49 Rapid Oral Presentation Monday, October 26 10:15 am – 11:45 am Breast DESTINY-Breast11: MRI-assessed objective responses during neoadjuvant treatment with trastuzumab deruxtecan (T-DXd) followed by paclitaxel + trastuzumab + pertuzumab vs. dose-dense doxorubicin + cyclophosphamide followed by THP in HER2+ early breast cancer J.F. Boileau 543RO Rapid Oral Presentation Friday, October 23 4:15 pm – 5:45 pm Patient-reported outcomes from DESTINY-Breast05: health-related quality of life with trastuzumab deruxtecan (T-DXd) versus trastuzumab emtansine (T-DM1) in patients with high-risk HER2 positive early breast cancer C. Barrios 539RO Rapid Oral Presentation Friday, October 23 4:15 pm – 5:45 pm Paired-biopsy multi-omic analysis reveals target-independent mechanisms of antibody-drug conjugate resistance in metastatic breast cancer P. Tarantino 4449RO Rapid Oral Presentation Monday, October 26 10:15 am – 11:45 am Trastuzumab deruxtecan (T-DXd) vs. physician’s choice of chemotherapy in HR+, HER2 low metastatic breast cancer: a DESTINY-Breast06 ctDNA molecular response analysis G. Curigliano 4279P Poster Presentation Friday, October 23 3:15 pm – 4:00 pm Trastuzumab deruxtecan (T-DXd) + pembrolizumab in previously treated human epidermal growth factor receptor 2-expressing advanced or metastatic breast cancer: primary analyses of the breast cohorts from the open-label, multicenter, phase 1b study DS8201-A-U106 H. Rugo 1771P Poster Presentation Saturday, October 24 12:00 pm – 12:45 pm DESTINY-Breast Respond HER2 low Europe non-interventional study of trastuzumab deruxtecan (T-DXd) in HER2 low metastatic breast cancer: update on baseline characteristics and anti-emetic treatment J.Y. Pierga 12P Poster Presentation Saturday, October 24 12:00 pm – 12:45 pm Improving accuracy in HER2 ultralow identification: multi-site validation of an AI-decision support tool B. Van der Vegt 1784P Poster Presentation Saturday, October 24 12:00 pm – 12:45 pm Comparative evaluation of 7 artificial intelligence tools for HER2-low and ultralow scoring in breast cancer J.S. Frenel 287P Poster Presentation Sunday, October 25 12:00 pm – 12:45 pm A global, interventional, open-label trial of trastuzumab deruxtecan (T-DXd)-based therapy followed by palbociclib, endocrine therapy, and dual HER2 blockade in first-line human epidermal growth factor receptor 2 positive, hormone receptor-positive advanced or metastatic breast cancer and retreatment with T-DXd (DESTINY-Breast Guide) S. Sammons 1795TiP Poster Presentation Saturday, October 24 12:00 pm – 12:45 pm Lung NeoCOAST-2: association of ctDNA clearance with clinical outcomes in a global platform phase 2 perioperative trial T. Cascone 4244RO Rapid Oral Presentation Sunday, October 25 8:30 am – 10:00 am Mechanisms of insensitivity to the datopotamab deruxtecan (Dato-DXd) payload in subgroups of patients with advanced non-small cell lung cancer in TROPION Lung01 N. Girard 4451P Poster Presentation Friday, October 23 3:15 pm – 4:00 pm Ifinatamab deruxtecan (I-DXd) in extensive-stage small cell lung cancer: IDeate-Lung01 updated results M. Ahn 3842P Poster Presentation Monday, October 26 12:00 pm – 12:45 pm Ovarian Raludotatug deruxtecan (R-DXd) + bevacizumab in participants with platinum-resistant recurrent ovarian cancer: results for cohort B-1 of the phase 1b/2 REJOICE (Ovarian02 study) A. Oaknin 1247RO Rapid Oral Presentation Saturday, October 24 8:30 am – 10:00 am Raludotatug deruxtecan (R-DXd) in patients with platinum-resistant ovarian cancer: an updated analysis of efficacy and tolerability from the phase 2 part of REJOICE-Ovarian01 K. Hasegawa 1331P Poster Presentation Monday, October 26 12:00 pm – 12:45 pm A randomized phase 2, open-label, multicenter, study of trastuzumab deruxtecan versus investigator’s choice chemotherapy in recurrent ovarian cancer that progressed on prior PARP inhibitor therapy: TROY (APGOT-OV14) J.Y. Lee 1335TiP Poster Presentation Monday, October 26 12:00 pm – 12:45 pm Gastric Quality-adjusted time without symptoms or toxicity (Q-TWiST) of trastuzumab deruxtecan (T-DXd) vs ramucirumab plus paclitaxel in second-line treatment of patients with HER2+ unresectable/metastatic gastric cancer/gastroesophageal junction adenocarcinoma from DESTINY-Gastric04 M. Gumus 2925P Poster Presentation Sunday, October 25 12:00 pm – 12:45 pm Perioperative trastuzumab deruxtecan plus capecitabine and durvalumab in HER2 positive gastric or gastroesophageal junction cancer: a phase II study (EPOC2003) D. Takahari 2888P Poster Presentation Sunday, October 25 12:00 pm – 12:45 pm PanTumor Final results of the TUXEDO-3 phase II trial of patritumab deruxtecan (HER3-DXd) in active brain metastases and leptomeningeal disease M. Preusser 690O Proffered Paper Presentation Sunday, October 25 10:15 am – 11:45 am Patritumab deruxtecan (HER3-DXd) in melanoma after anti-PD-(L)1 therapy: primary analysis from HERTHENA-PanTumor01 M. McKean 2073RO Rapid Oral Presentation Sunday, October 25 10:15 am – 11:45 am ESPERANZA: Results from an external comparator study of trastuzumab deruxtecan in HER2 IHC3+ solid tumors F. Meric-Bernstam 1014P Poster Presentation Friday, October 23 3:15 pm – 4:00 pm   About the ADC Portfolio of Daiichi Sankyo The Daiichi Sankyo ADC portfolio consists of nine ADCs in clinical development crafted from ADC technology discovered in-house by Daiichi Sankyo. The DXd ADC Technology platform of Daiichi Sankyo consists of seven ADCs in clinical development where each ADC is comprised of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers. The DXd ADCs include Enhertu and Datroway, which are being jointly developed and commercialized globally with AstraZeneca, and ifinatamab deruxtecan (I-DXd), raludotatug deruxtecan (R-DXd) and patritumab deruxtecan (HER3-DXd), which are being jointly developed and commercialized globally with Merck & Co., Inc, Rahway, NJ, USA. DS-3939 and DS3790 are being developed by Daiichi Sankyo. Additional ADCs being developed by Daiichi Sankyo include DS3610, which consists of an antibody attached to a novel payload that acts as an agonist of STING, and DS1025, which consists of a CD25 directed antibody attached to an immuno-oncology optimized cytotoxic payload. Ifinatamab deruxtecan, raludotatug deruxtecan, patritumab deruxtecan, DS-3939, DS3610, DS3790 and DS1025 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 (TSE: 4568) is a global healthcare company committed to becoming a trusted healthcare innovator, transforming the lives of people through its strength in science and technology. The company discovers and develops new standards of care to address diverse medical needs to fulfill its purpose of contributing to the enrichment of quality of life around the world. With a strategic focus on oncology, Daiichi Sankyo is advancing an industry-leading antibody drug conjugate portfolio along with identifying new breakthrough generating technologies to deliver practice-changing medicines to patients, healthcare professionals and society. For more information, please visit www.daiichisankyo.com. MEDIA CONTACTS: Global: Jennifer Brennan Jennifer.brennan@daiichisankyo.com +1 908 900 3183 (mobile) INVESTOR RELATIONS CONTACT: DaiichiSankyoIR_jp@daiichisankyo.com Japan: DS-PR_jp@daiichisankyo.com

Oct 2, 2026

Tokyo – (October 2, 2026) – Daiichi Sankyo (TSE: 4568) and AstraZeneca (LSE/STO/NYSE: AZN) have entered into a clinical trial collaboration agreement with Summit Therapeutics Inc. (Nasdaq: SMMT) to evaluate Datroway® (datopotamab deruxtecan) in combination with ivonescimab across multiple tumor types including lung and breast cancers. The companies intend to begin with a phase 3 trial in first-line triple negative breast cancer (TNBC). Datroway is a specifically engineered TROP2 directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo and being jointly developed and commercialized by Daiichi Sankyo and AstraZeneca. “At Daiichi Sankyo, we are focused on maximizing the potential of our DXd antibody drug conjugate portfolio through innovative combinations and strategic collaborations that support the continued advancement of our pipeline,” said John Tsai, MD, Global Head, R&D, Daiichi Sankyo. “We are encouraged by the opportunity to explore ivonescimab in combination with Datroway to potentially deliver clinically meaningful benefit to patients.” “Central to our strategy to transform cancer outcomes is harnessing the power of immunotherapy and antibody drug conjugate combinations to drive deeper, more durable responses,” said Susan Galbraith, Executive Vice President, Oncology Hematology R&D, AstraZeneca. “We believe the combination of Datroway and ivonescimab has the potential to make a meaningful difference in multiple tumor types including lung and breast cancers.” “We believe this collaboration with Daiichi Sankyo and AstraZeneca reflects increasing conviction in ivonescimab’s potential as a foundational next-generation immunotherapy and advances our ambition for ivonescimab to become the global PD-1/VEGF partner of choice for novel combinations,” said Maky Zanganeh, President and Co-Chief Executive Officer, Summit Therapeutics. “Beginning with a phase 3 study in first-line triple negative breast cancer, this collaboration represents an important expansion of Summit’s global development program into breast cancer and a path for additional solid tumor settings.” Under the terms of the agreement, each company will contribute their respective compound for the planned combination trials, which will be sponsored by AstraZeneca or Daiichi Sankyo. AstraZeneca, Daiichi Sankyo and Summit will each contribute to trial costs, and each company will retain development and commercial rights to their respective medicines. Ivonescimab is a novel, potential first-in-class bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule. About Datroway Datroway (datopotamab deruxtecan; datopotamab deruxtecan-dlnk in the U.S. only) is a TROP2 directed ADC. Designed using the proprietary DXd ADC Technology of Daiichi Sankyo, Datrowayis one of seven DXd ADCs in the oncology pipeline of Daiichi Sankyo, and one of the most advanced programs in AstraZeneca’s ADC scientific platform. Datroway is comprised of a humanized anti-TROP2 IgG1 monoclonal antibody, developed in collaboration with Sapporo Medical University, attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers. Datroway (6 mg/kg) is approved in more than 30 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic TNBC who are not candidates for PD-1/PD-L1 inhibitor therapy based on the results from the TROPION-Breast02 trial. Datroway (6 mg/kg) is approved in more than 45 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic HR positive, HER2 negative (IHC 0, IHC 1+ or IHC 2+/ISH-) breast cancer who have received prior endocrine-based therapy and chemotherapy for unresectable or metastatic disease based on the results from the TROPION-Breast01 trial. Datroway (6 mg/kg) is approved in Brazil, Russia, Singapore and the U.S. for the treatment of adult patients with locally advanced or metastatic EGFR-mutated non-small cell lung cancer (NSCLC) who have received prior EGFR-directed therapy and platinum-based chemotherapy based on the results from TROPION-Lung05 and TROPION-Lung01 trials. Continued approval for this indication in the U.S. may be contingent upon verification and description of clinical benefit in a confirmatory trial. About the Datroway Clinical Development Program A comprehensive global clinical development program is underway with more than 20 trials evaluating the efficacy and safety of Datroway across multiple cancers, including non-small cell lung cancer (NSCLC), TNBC and urothelial cancer. The program includes eight phase 3 trials in lung cancer, five phase 3 trials in breast cancer and one phase 3 and one phase 2/3 trial in urothelial cancer evaluating Datroway as a monotherapy and in combination with other cancer treatments in various settings. About the Daiichi Sankyo and AstraZeneca Collaboration Daiichi Sankyo and AstraZeneca entered into a global collaboration to jointly develop and commercialize Enhertu® in March 2019 and Datrowayin July 2020, except in Japan where Daiichi Sankyo maintains exclusive rights for each ADC. Daiichi Sankyo is responsible for the manufacturing and supply of Enhertu and Datroway. About the ADC Portfolio of Daiichi Sankyo The Daiichi Sankyo ADC portfolio consists of nine ADCs in clinical development crafted from ADC technology discovered in-house by Daiichi Sankyo. The DXd ADC Technology platform of Daiichi Sankyo consists of seven ADCs in clinical development where each ADC is comprised of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers. The DXd ADCs include Enhertu and Datroway, which are being jointly developed and commercialized globally with AstraZeneca, and ifinatamab deruxtecan (I-DXd), raludotatug deruxtecan (R-DXd) and patritumab deruxtecan (HER3-DXd), which are being jointly developed and commercialized globally with Merck & Co., Inc, Rahway, NJ, USA. DS-3939 and DS3790 are being developed by Daiichi Sankyo. Additional ADCs being developed by Daiichi Sankyo include DS3610, which consists of an antibody attached to a novel payload that acts as an agonist of STING, and DS1025, which consists of a CD25 directed antibody attached to an immuno-oncology optimized cytotoxic payload. Ifinatamab deruxtecan, raludotatug deruxtecan, patritumab deruxtecan, DS-3939, DS3610, DS3790 and DS1025 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 (TSE: 4568) is a global healthcare company committed to becoming a trusted healthcare innovator, transforming the lives of people through its strength in science and technology. The company discovers and develops new standards of care to address diverse medical needs to fulfill its purpose of contributing to the enrichment of quality of life around the world. With a strategic focus on oncology, Daiichi Sankyo is advancing an industry-leading antibody drug conjugate portfolio along with identifying new breakthrough generating technologies to deliver practice-changing medicines to patients, healthcare professionals and society. For more information, please visit www.daiichisankyo.com. MEDIA CONTACTS: Global: Jennifer Brennan jennifer.brennan@daiichisankyo.com + 1 908 900 3183 (mobile) INVESTOR RELATIONS CONTACT: DaiichiSankyoIR_jp@daiichisankyo.com Japan: DS-PR_jp@daiichisankyo.com