Based on DESTINY-Breast09 Phase III trial which showed Enhertu plus pertuzumab reduced the risk of disease progression or death by 44% vs. THP with median progression-free survival exceeding three years. If approved, AstraZeneca and Daiichi Sankyo's Enhertu plus pertuzumab would become first new treatment in the EU in more than a decade for 1st-line HER2-positive metastatic breast cancer.
AstraZeneca and Daiichi Sankyo's Enhertu (trastuzumab deruxtecan) in combination with pertuzumab has been recommended for approval in the European Union (EU) for the 1st-line treatment of adult patients with unresectable or metastatic HER2-positive breast cancer.
The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) based its positive opinion on results from the DESTINY-Breast09 Phase III trial presented at the 2025 American Society of Clinical Oncology Annual Meeting and subsequently published in The New England Journal of Medicine.1
Susan Galbraith, Executive Vice President, Oncology Haematology R&D, AstraZeneca, said: "HER2-positive metastatic breast cancer is an aggressive subtype, so starting patients on an effective HER2-targeted treatment early and continuing it for as long as they benefit can have a meaningful impact on long-term outcomes. DESTINY-Breast09 sets a new benchmark with a median progression-free survival of more than three years, underscoring the potential of Enhertu plus pertuzumab to redefine first-line treatment for patients with HER2-positive metastatic breast cancer."
John Tsai, Global Head, R&D, Daiichi Sankyo, said: "Enhertu in combination with pertuzumab improved progression-free survival by more than one year compared with the current first-line standard of care, representing a meaningful advantage early in the treatment of patients with metastatic HER2-positive disease. Today's positive CHMP opinion brings us closer to making Enhertu available in the EU as a first-line treatment option for eligible patients with HER2-positive metastatic breast cancer, marking an important milestone in moving this medicine earlier in the treatment pathway."
In DESTINY-Breast09, Enhertu in combination with pertuzumab reduced the risk of disease progression or death by 44% versus a taxane, trastuzumab and pertuzumab (THP) (based on a hazard ratio of 0.56; 95% confidence interval [CI]: 0.44-0.71; p<0.00001) in patients with HER2-positive metastatic breast cancer who had not received prior chemotherapy or HER2-targeted therapy or had received neoadjuvant or adjuvant HER2-targeted therapy more than six months before the diagnosis of advanced or metastatic disease. Median progression-free survival (PFS) was 40.7 months with Enhertu in combination with pertuzumab compared to 26.9 months with THP. The PFS benefit was consistent across subgroups, including for the prespecified stratification factors of hormone receptor status, de novo or recurrent disease and PIK3CA mutation status.
The safety profile of Enhertu plus pertuzumab was consistent with the known profiles of each individual therapy with no new safety concerns identified.
Enhertu in combination with pertuzumab is approved in the US, Switzerland and other countries as a 1st-line treatment for patients with metastatic HER2-positive breast cancer based on the results from the DESTINY-Breast09 trial.
Enhertu is also under review in the EU for patients with HER2-positive breast cancer who have residual invasive disease after neoadjuvant HER2-targeted treatment based on data from the DESTINY-Breast05 trial.
Enhertu is a specifically engineered HER2-directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo and being jointly developed and commercialised by AstraZeneca and Daiichi Sankyo.
HER2-positive metastatic breast cancer
Breast cancer is the most common cancer in women worldwide and the leading cause of cancer-related death among women.2 Approximately, 2.4 million breast cancer cases were diagnosed in 2024, with more than 690,000 deaths globally.2 In Europe, approximately 540,000 cases of breast cancer are diagnosed annually, with more than 140,000 deaths.3 While survival rates are high for those diagnosed with early breast cancer, only about 30% of patients diagnosed with or whose disease has progressed to metastatic disease are expected to live five years following diagnosis.4
HER2 is a tyrosine kinase receptor growth-promoting protein expressed on the surface of many types of tumours including breast cancer.5 HER2 protein overexpression may occur as a result of HER2 gene amplification.4 Approximately one in five cases of breast cancer is considered HER2-positive.5
HER2-positive metastatic breast cancer is an aggressive disease driven by overexpression or amplification of HER2 that affects 15% to 20% of patients with metastatic breast cancer.6 While HER2-targeted therapies have improved outcomes, prognosis remains poor with most patients experiencing disease progression within two years of first-line treatment with THP, which has been the standard of care for more than a decade.6-8 Further, approximately one in three patients do not receive any treatment following first-line therapy due to disease progression or death.10,11
DESTINY-Breast09
DESTINY-Breast09 is a global, multicentre, randomised, open-label, Phase III trial evaluating the efficacy and safety of Enhertu (5.4 mg/kg) either alone or in combination with pertuzumab versus standard of care THP as first-line treatment in patients with HER2-positive metastatic breast cancer who had not received prior chemotherapy or HER2-targeted therapy or had received neoadjuvant or adjuvant HER2-targeted therapy more than six months before the diagnosis of advanced or metastatic disease.
Patients were randomised 1:1:1 to receive either Enhertu monotherapy with a pertuzumab matching placebo; Enhertu in combination with pertuzumab; or THP. Randomisation was stratified by prior treatment (de novo metastatic disease versus progression from early-stage disease), hormone receptor (HR) status and PIK3CA mutation status.
The primary endpoint of DESTINY-Breast09 is PFS as assessed by BICR in both the Enhertu monotherapy and Enhertu combination arms. Secondary endpoints include investigator-assessed PFS, overall survival, ORR, duration of response, pharmacokinetics and safety. The investigational arm assessing Enhertu monotherapy versus THP remains blinded to patients and investigators and will continue to the final PFS analysis.
DESTINY-Breast09 enrolled 1,157 patients across multiple sites in Africa, Asia, Europe, North America and South America. For more information about the trial, visit ClinicalTrials.gov.
Enhertu
Enhertu is a HER2-directed ADC. Designed using Daiichi Sankyo's proprietary DXd ADC Technology, Enhertu is the lead ADC in the oncology portfolio of Daiichi Sankyo and the most advanced programme in AstraZeneca's ADC scientific platform. Enhertu consists of a HER2 monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.
Enhertu (5.4mg/kg) followed by THP is approved in the US, China and Singapore as a neoadjuvant treatment for adult patients with HER2-positive (IHC 3+ or ISH+) Stage II or III breast cancer based on the results from the DESTINY-Breast11 trial. Continued approval in China for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.
Enhertu (5.4mg/kg) is approved in the US as an adjuvant treatment for adult patients with HER2-positive (IHC 3+ or ISH+) breast cancer who have residual invasive disease following trastuzumab (with or without pertuzumab) and taxane-based treatment based on the DESTINY-Breast05 trial.
Enhertu (5.4mg/kg) in combination with pertuzumab is approved in the US, Switzerland, India, Israel, United Arab Emirates, Saudi Arabia, Korea and Singapore as a 1st-line treatment for adult patients with unresectable or metastatic HER2-positive (IHC 3+ or ISH+) breast cancer based on the results from the DESTINY-Breast09 trial.
Enhertu (5.4mg/kg) is approved in more than 100 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic HER2-positive (IHC 3+ or ISH+) breast cancer who have received a prior anti-HER2-based regimen, either in the metastatic setting or in the neoadjuvant or adjuvant setting, and have developed disease recurrence during or within six months of completing therapy based on the results from the DESTINY-Breast03 trial.
Enhertu (5.4mg/kg) is approved in more than 75 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic hormone receptor (HR)-positive, HER2-low (IHC 1+ or IHC 2+/ ISH-) or HER2-ultralow (IHC 0 with membrane staining) breast cancer, as determined by a locally or regionally authorised test, that have progressed on one or more endocrine therapies in the metastatic setting based on the results from the DESTINY-Breast06 trial.
Enhertu (5.4mg/kg) is approved in more than 100 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer who have received a prior systemic therapy in the metastatic setting or developed disease recurrence during or within six months of completing adjuvant chemotherapy based on the results from the DESTINY-Breast04 trial.
Enhertu (5.4mg/kg) is approved in more than 80 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic non-small cell lung cancer (NSCLC) whose tumours have activating HER2 (ERBB2) mutations, as detected by a locally or regionally approved test, and who have received a prior systemic therapy based on the results from the DESTINY-Lung02 and/or DESTINY-Lung05 trials. Continued approval in China and the US for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.
Enhertu (6.4mg/kg) is approved in more than 90 countries/regions worldwide for the treatment of adult patients with locally advanced or metastatic HER2-positive (IHC 3+ or IHC 2+/ISH+) gastric or gastroesophageal junction (GEJ) adenocarcinoma who have received a prior trastuzumab-based regimen based on the results from the DESTINY-Gastric01, DESTINY-Gastric02 and/or DESTINY-Gastric04 trials.
Enhertu (5.4mg/kg) is approved in more than 45 countries/regions worldwide for the treatment of adult patients with unresectable or metastatic HER2-positive (IHC 3+) solid tumours who have received prior systemic treatment and have no satisfactory alternative treatment options based on efficacy results from the DESTINY-PanTumor02, DESTINY-Lung01, DESTINY-CRC02 and/or HERALD trials. Continued approval in the US for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.
Enhertu clinical development programme
A comprehensive global clinical development programme is underway evaluating the efficacy and safety of Enhertu as a monotherapy, in combination or sequentially with other cancer medicines across multiple HER2-targetable cancers.
Daiichi Sankyo collaboration
AstraZeneca and Daiichi Sankyo entered into a global collaboration to jointly develop and commercialise Enhertu in March 2019 and Datroway (datopotamab deruxtecan) in 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.
AstraZeneca in breast cancer
Driven by a growing understanding of breast cancer biology, AstraZeneca is challenging, and redefining, the current clinical paradigm for how breast cancer is classified and treated to deliver even more effective treatments to patients in need - with the bold ambition to one day eliminate breast cancer as a cause of death.
AstraZeneca has a comprehensive portfolio of approved and promising compounds in development that leverage different mechanisms of action to address the biologically diverse breast cancer tumour environment.
With Enhertu, AstraZeneca and Daiichi Sankyo are aiming to improve outcomes in previously treated HER2-positive, HER2-low and HER2-ultralow metastatic breast cancer, and expanding its potential in earlier lines of treatment and in new breast cancer settings.
In HR-positive breast cancer, AstraZeneca continues to improve outcomes with foundational medicines Faslodex and Zoladex (goserelin) and aims to reshape the HR-positive space with first-in-class AKT inhibitor, Truqap (capivasertib), the TROP-2-directed ADC, Datroway (datopotamab deruxtecan) and next-generation oral SERD, Etcamah.
PARP inhibitor Lynparza (olaparib) is a targeted treatment option that has been studied in early and metastatic breast cancer patients with an inherited BRCA mutation. AstraZeneca with MSD (Merck & Co., Inc. in the US and Canada) continue to research Lynparza in these settings. AstraZeneca is also exploring the potential of saruparib, a potent and selective inhibitor of PARP1, in combination with Etcamah in BRCA-mutated, HR-positive, HER2-negative advanced breast cancer.
To bring much-needed treatment options to patients with triple-negative breast cancer, an aggressive form of breast cancer, AstraZeneca is collaborating with Daiichi Sankyo to evaluate the potential of Datroway alone and in combination with immunotherapy Imfinzi (durvalumab).
AstraZeneca in oncology
AstraZeneca is leading a revolution in oncology with the ambition to provide cures for cancer in every form, following the science to understand cancer and all its complexities to discover, develop and deliver life-changing medicines to patients.
The Company's focus is on some of the most challenging cancers. It is through persistent innovation that AstraZeneca has built one of the most diverse portfolios and pipelines in the industry, with the potential to catalyse changes in the practice of medicine and transform the patient experience.
AstraZeneca has the vision to redefine cancer care and, one day, eliminate cancer as a cause of death.
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