Trastuzumab Deruxtecan Versus Trastuzumab Emtansine for Breast Cancer: A Plain Language Summary of the DESTINY-Breast03 Study

Plain Language Summary

What is this summary about?

This is a summary of a publication about the DESTINY-Breast03 study, which was published in the New England Journal of Medicine in March 2022. The study included 524 adults with advanced breast cancer that is HER2-positive, which means it has high levels of a protein called HER2. All of the participants in this study had their cancer worsen after previously receiving treatment. The treatment that was previously given to participants was a combination of a drug called trastuzumab with a type of chemotherapy called a taxane. The researchers wanted to know whether a drug called trastuzumab deruxtecan (T-DXd) could improve participants’ cancer more than the standard treatment. The standard treatment is a drug called trastuzumab emtansine (T-DM1). The researchers looked at the results of this study before it was finished. This is a summary of those results.

What were the results?

Researchers in this study found that the risk of dying or the participants’ cancer getting worse was reduced by 72% in the T-DXd group compared with the T-DM1 group. This is also called progression-free survival.

79.7% of participants in the T-DXd group had their tumors shrink significantly or disappear, compared to 34.2% of those in the T-DM1 group.

During the study, 10.9% of participants who received T-DXd had serious drug-related medical problems, compared to 6.1% who received T-DM1.

Of the participants who received T-DXd, 10.5% experienced drug-related interstitial lung disease (ILD) or pneumonitis, compared to 1.9% of those who received T-DM1. ILD and pneumonitis are potentially serious lung problems.

When the researchers first looked at the results, they could not yet be certain that T-DXd helped participants survive longer overall than T-DM1. But, when they looked at the results later in the study, they found that T-DXd did help participants to survive longer overall than T-DM1. These newer results were published separately and are not part of this summary. A link to more information about the newer results can be found at the end of this summary.

What do the results mean?

T-DXd gave participants a meaningful benefit overall compared to T-DM1. T-DXd could be a treatment option for people with advanced HER2-positive breast cancer that has been previously treated.

Clinical Trial Registration: NCT03529110 (DESTINY-Breast03) (ClinicalTrials.gov)

This is an abstract of the Plain Language Summary of Publication article.

To read the full Plain Language Summary of this article, click here to view the PDF.

Link to original article here

Keywords::

• breast
• chemotherapy
• women’s health

Acknowledgments

Daiichi Sankyo and AstraZeneca would like to thank the clinical study participants and their family members and caregivers. They would also like to thank the staff members at the study centers who cared for the participants in the clinical study.

Financial & competing interests disclosure

Javier Cortés reports receiving personal fees for consulting and advisory roles from Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp & Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, Expres2ion Biotechnologies; receiving honoraria from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck Sharp & Dohme, Daiichi Sankyo, AstraZeneca; receiving research funding to the Institution from Roche, Ariad Pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer Healthcare, Eisai, F.Hoffman-La Roche, Guardant Health, Merck Sharp & Dohme, Pfizer, Piqur Therapeutics, Puma C, Queen Mary University of London; receiving stock from MedSIR, Nektar Pharmaceuticals, Leuko (relative); receiving travel, accommodation and expenses from Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, AstraZeneca, Gilead and reports the following patents: Pharmaceutical Combinations of A Pi3k Inhibitor And A Microtubule Destabilizing Agent. Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde. WO 2014/199294 A. ISSUED, Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy. Aleix Prat, Antonio Llombart, Javier Cortés. US 2019/0338368 A1. LICENSED.

Medical writing disclosure

Medical writing support for this summary was funded by Daiichi Sankyo and provided by the Center for Information & Study on Clinical Research Participation (CISCRP), a non-profit organization focused on educating and informing the public about clinical research participation. Medical writing and editorial assistance in the development of this summary were provided by Samuel Entwisle, PhD, and Matt Chapman of CISCRP.