On May 28, 2026 Daiichi Sankyo (TSE: 4568) reported it will present new clinical research across its oncology portfolio with more than 25 abstracts in multiple cancers at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting (#ASCO26).

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Data at ASCO (Free ASCO Whitepaper) will highlight the company’s progress toward advancing new standards of care for patients with cancer, including new analyses from five landmark trials in breast and gastric cancer, including the DESTINY-Breast05 (#516), DESTINY-Breast06 (#1063), DESTINY-Breast09 (#1021) and DESTINY-Gastric04 (#4111) phase 3 trials of Enhertu (trastuzumab deruxtecan), and the TROPION-Breast02 (#1002) phase 3 trial of Datroway (datopotamab deruxtecan). Additional results from earlier phase trials as well as trials-in-progress across new medicines being developed through the company’s breakthrough generating technology (BGT), a platform-based drug discovery model designed to deliver innovative medicines to patients faster, will be highlighted.

Data from DESTINY-Breast05 formed the basis of one of two new Enhertu indications recently approved in the U.S. for certain patients with early-stage HER2 positive breast cancer and data from DESTINY-Gastric04 was included as part of a label update to expand the use of Enhertu in Japan and China to include the second-line treatment of patients with HER2 positive metastatic gastric cancer. Additionally, results from TROPION-Breast02 formed the basis of the recent U.S. approval of Datroway in patients with metastatic triple negative breast cancer (TNBC) who are not candidates for PD-1/PD-L1 inhibitor therapy, the first antibody drug conjugate (ADC) to be approved in this setting of TNBC.

"The approvals received just prior to ASCO (Free ASCO Whitepaper) for Enhertu and Datroway, two of our leading DXd antibody drug conjugates, together with the strong science being showcased across our pipeline, highlight the momentum of our oncology portfolio," said John Tsai, MD, Global Head, R&D, Daiichi Sankyo. "Daiichi Sankyo is committed to creating new standards of care for patients with cancer and continues to leverage its scientific and technological expertise to advance innovation."

Additional Enhertu Data Spans Broad Range of HER2 Expressing Cancers
Additional research updates across several additional HER2 expressing cancers include oral and poster sessions highlighting the preliminary safety run-in results from the DESTINY-Ovarian01 (#5554) phase 3 trial evaluating Enhertu in combination with bevacizumab compared to bevacizumab monotherapy as a first-line maintenance therapy in patients with HER2 expressing ovarian cancer; the primary analysis from part 1 of the DESTINY-PanTumor03 (#3026) phase 2 trial evaluating Enhertu in pretreated patients in China with HER2 positive (IHC 3+) solid tumors (excluding breast and gastric cancer); and, findings from the MYTHOS (#6011) phase 2 trial evaluating Enhertu in patients with HER2-low recurrent or metastatic salivary gland cancer.

Additional breast and gastric cancer data for Enhertu include an oral presentation from one arm of the DESTINY-Breast07 (#1012) phase 1b/2 trial evaluating Enhertu in combination with durvalumab as a first-line treatment in patients with HER2 positive metastatic breast cancer and a poster presentation highlighting a safety analysis from the DESTINY-Gastric03 (#4022) phase 1b/2 trial evaluating Enhertu in combination with chemotherapy and immunotherapy as a first-line treatment in patients with HER2 expressing metastatic gastric cancer, gastroesophageal junction (GEJ) adenocarcinoma or esophageal adenocarcinoma.

Results from cohort two of the EPOC2203 (#4024) phase 1b/2 trial evaluating Enhertu in combination with nivolumab and capecitabine and oxaliplatin in patients with HER2 low gastroesophageal adenocarcinoma and an exploratory analysis of translational data from the EPOC2003 (#3129) phase 2 trial evaluating neoadjuvant chemotherapy in combination with Enhertu in patients with HER2 positive gastric cancer will be highlighted as poster presentations.

New Data and Trials-in-Progress Presentations Across Oncology Portfolio
Poster presentations will include a trial-in-progress update of REJOICE-Ovarian01 (TPS5637) for the phase 3 part of a phase 2/3 trial evaluating raludotatug deruxtecan (R-DXd) compared to treatment of physician’s choice in patients with platinum-resistant ovarian cancer. Two additional poster presentations will highlight an exposure-response analysis (#5570) and a population pharmacokinetic analysis (#5571) of data from both the REJOICE-Ovarian01 phase 2/3 trial and the phase 1 trial evaluating raludotatug deruxtecan in patients with advanced ovarian cancer or renal cell carcinoma.

An oral presentation will highlight results from a phase 1/2 trial (#6504) of Vanflyta (quizartinib) plus decitabine and venetoclax in patients with newly diagnosed or relapsed/refractory FLT3-ITD acute myeloid leukemia.

Trials-in-progress poster presentations across the DXd ADC portfolio include the TROPION-Urothelial03 (TPS4642) phase 2/3 trial evaluating Datroway and platinum chemotherapy compared to gemcitabine plus platinum chemotherapy in patients with locally advanced or metastatic urothelial carcinoma; the HERTHENA-Breast04 (TPS1149) phase 3 trial evaluating patritumab deruxtecan (HER3-DXd) compared to treatment of physician’s choice in patients with HR positive, HER2 negative unresectable locally advanced or metastatic breast cancer; and the DESTINY-PanTumor04 (TPS11202) hybrid observational trial evaluating Enhertu in patients with HER2 positive (IHC 3+) solid tumors.

Trials-in-Progress Presentations Highlight Breakthrough Generating Technology Focus
Daiichi Sankyo is leveraging its strength in science and technology to create new medicines for patients with cancer through its BGT approach which is designed to deliver innovative medicines to patients faster and with a higher probability of success. Trials-in-progress poster presentations featuring three potential new medicines include DS3610 (TPS3159), a STING (stimulator of interferon genes) ADC, in patients with advanced or metastatic solid tumors; DS5361 (TPS2680), a small-molecule, nonsense-mediated mRNA decay inhibitor, in patients with advanced or metastatic solid tumors; and, DS9051 (TPS3179), a novel targeted protein degradation molecule, in patients with advanced or metastatic adrenocortical carcinoma or metastatic castration-resistant prostate cancer.

Overview of clinical data and trials-in-progress from oncology pipeline of Daiichi Sankyo include:

Presentation Title

Author

Abstract

Presentation (CDT)

Breast

A DESTINY-Breast09 analysis of treatment duration and clinical outcomes by best response to trastuzumab deruxtecan (T-DXd) + pertuzumab

Y. Park

1021

Rapid Oral Presentation
Sunday, May 31
11:30 am – 1:00 pm

Secondary safety analysis of trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in DESTINY-Breast05: clinical and demographic risk factors of interstitial lung disease and radiation pneumonitis

M. Untch

516

Rapid Oral Presentation
Monday, June 1
9:45 – 11:15 am

Neoadjuvant rilvegostomig (R) + trastuzumab deruxtecan (T-DXd) in high-risk HER2-negative breast cancer: Results from the I-SPY 2.2 trial

C. O’Sullivan

LBA514

Rapid Oral Presentation
Monday, June 1
9:45 – 11:15 am

Trastuzumab deruxtecan (T-DXd) + durvalumab in patients with previously untreated HER2 positive unresectable/metastatic breast cancer (mBC): final analysis from DESTINY-Breast07

S. Loi

1012

Oral Presentation
Sunday, May 31
8:30 – 10:00 am

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: additional efficacy endpoints from the TROPION-Breast02 study

D. Cescon

1002

Oral Presentation
Tuesday, June 2
9:45 am – 12:45 pm

Impact of adherence to interstitial lung disease (ILD)/pneumonitis toxicity management guidelines on ILD/pneumonitis outcomes: a retrospective analysis of patients treated with trastuzumab deruxtecan (T-DXd) in DESTINY-Breast06

C. Mateo

1063

Poster Session
Monday, June 1
1:30 – 4:30 pm

HERTHENA-Breast04: a phase 3, randomized, open-label study evaluating the efficacy and safety of patritumab deruxtecan (HER3-DXd) versus treatment of physician’s choice in hormone receptor positive (HR +)/HER2-) unresectable locally advanced or metastatic breast cancer

B. Pistilli

TPS1149

Poster Session
Monday, June 1
1:30 – 4:30 pm

Identifying patients with human epidermal growth factor receptor 2 (HER2) low and ultralow breast cancer: use of digital, artificial intelligence-based computational algorithms to assist HER2 scoring by pathologists

S. Krishnamurthy

1022

Poster Session
Monday, June 1
1:30 – 4:30 pm

Gastric

Additional health-related quality of life analysis from DESTINY-Gastric04, a randomized phase 3 study of trastuzumab deruxtecan (T-DXd) vs ramucirumab + paclitaxel in patients with HER2 positive unresectable/metastatic gastric cancer/gastroesophageal junction adenocarcinoma

K. Shitara

4111

Poster Session
Saturday, May 30
9:00 am – 12:00 pm

First-line trastuzumab deruxtecan (T-DXd)-based regimens in advanced HER2 expressing gastric cancer, gastroesophageal junction adenocarcinoma, or esophageal adenocarcinoma: safety results from DESTINY-Gastric03 Part 2 arms D and F, and Part 4

Y. Janjigian

4022

Poster Session
Saturday, May 30
9:00 am – 12:00 pm

An open-label phase 1b/2 study of trastuzumab deruxtecan combined with nivolumab and CAPOX in patients with HER2 low gastroesophageal adenocarcinoma (EPOC2203)

Y. Aoki

4024

Poster Session
Saturday, May 30
9:00 am – 12:00 pm

Tumor and immune microenvironment remodeling with neoadjuvant trastuzumab deruxtecan in HER2 positive gastric cancer: exploratory analyses from the phase 2 EPOC2003 study

A. Kawazoe

3129

Poster Session
Saturday, May 30
1:30 – 4:30 pm

Ovarian

Trastuzumab deruxtecan (T-DXd) + bevacizumab (BEV) as first-line (1L) maintenance therapy in patients with HER2 expressing ovarian cancer: results from the DESTINY-Ovarian01 safety run-in

A. Gonzalez Martin

5554

Poster Session
Monday, June 1
9:00 am – 12:00 pm

REJOICE-Ovarian01: phase 3 part of a phase 2/3 study evaluating raludotatug deruxtecan (R-DXd) versus treatment of physician’s choice in patients with platinum-resistant ovarian cancer

D. Richardson

TPS5637

Poster Session
Monday, June 1
9:00 am – 12:00 pm

Exposure-response analyses of efficacy and safety with raludotatug deruxtecan (R-DXd), a CDH6-directed ADC, to inform dose selection for phase 3 development in platinum-resistant ovarian cancer

F. Hurtado

5570

Poster Session
Monday, June 1
9:00 am – 12:00 pm

Population pharmacokinetic analysis of raludotatug deruxtecan (R-DXd), a CDH6-directed ADC, in patients with advanced ovarian cancer or renal cell carcinoma

F. Hurtado

5571

Poster Session
Monday, June 1
9:00 am – 12:00 pm

Urothelial

TROPION-Urothelial03: a phase 2/3 study of datopotamab deruxtecan (Dato-DXd) + platinum chemotherapy vs gemcitabine + platinum chemotherapy in participants with locally advanced or metastatic urothelial carcinoma with progression on or after enfortumab vedotin + pembrolizumab

M. Galsky

TPS4642

Poster Session
Sunday, May 31
9:00 am – 12:00 pm

Salivary

Trastuzumab deruxtecan in patients with HER2 low recurrent/metastatic salivary gland carcinoma: results from the phase 2 MYTHOS trial

I. Kinoshita

6011

Oral Presentation
Monday, June 1
8:00 – 9:30 am

AML

Quizartinib in combination with decitabine and venetoclax for newly diagnosed and relapsed/refractory FLT3 mutated acute myeloid leukemia

M. Yilmaz

6504

Oral Presentation
Tuesday, June 2
9:45 am – 12:45 pm

Pan Tumor

Trastuzumab deruxtecan (T-DXd) for pretreated patients in China with HER2 IHC 3+ solid tumors: DESTINY-PanTumor03 Part 1 primary analysis

Y. Zhang

3026

Poster Session
Saturday, May 30
1:30 – 4:30 pm

A pragmatic, hybrid observational study evaluating the effectiveness of trastuzumab deruxtecan (T-DXd) in patients with HER2 IHC3+ solid tumors: DESTINY-PanTumor04

B. Monk

TPS11202

Poster Session
Monday, June 1
9:00 am – 12:00 pm

HER2 independent antitumor and pharmacodynamic responses to trastuzumab deruxtecan in patients with advanced solid tumors

S. Shin

3031

Poster Session
Saturday, May 30
1:30 – 4:30 pm

Topoisomerase 1 and DNA damage: pharmacodynamic responses and mechanism of trastuzumab deruxtecan in HER2-expressing advanced solid tumors

D. Wilsker

3092

Poster Session
Saturday, May 30
1:30 – 4:30 pm

BGT

A phase 1, first-in-human study of DS3610, a stimulator of interferon genes (STING) agonist ADC, in patients with advanced/metastatic solid tumors

S. Koganemaru

TPS3159

Poster Session
Saturday, May 30
1:30 – 4:30 pm

A phase 1, first-in-human study of DS5361, a small-molecule, nonsense-mediated mRNA decay inhibitor, in patients with advanced/metastatic solid tumors (Parts 1 and 2)

S. Sen

TPS2680

Poster Session
Saturday, May 30
1:30 – 4:30 pm

A phase 1, first-in-human study of DS9051, a novel targeted protein degradation molecule, in patients with advanced/metastatic adrenocortical carcinoma or metastatic castration-resistant prostate cancer

M. Patel

TPS3179

Poster Session
Saturday, May 30
1:30 – 4:30 pm

(Press release, Daiichi Sankyo, MAY 28, 2026, https://www.businesswire.com/news/home/20260528097415/en/Daiichi-Sankyo-Showcases-Progress-Across-Industry-Leading-Oncology-Portfolio-with-Latest-Research-Updates-at-ASCO [SID1234666173])