What the trial was testing
The DESTINY-Breast03 enrolled 524 patients with breast cancer. The study was sponsored by Daiichi Sankyo and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
72% lower risk of cancer progression vs. the previous standard treatment.
New England Journal of Medicine · 2022 · NCT03529110
These findings — that of cancer progression on trastuzumab deruxtecan vs. trastuzumab emtansine in HER2+ metastatic breast cancer — were published in the New England Journal of Medicine and represent the headline result of the study.
Researchers tracked outcomes across 524 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with breast cancer, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
Trastuzumab deruxtecan (Enhertu) is FDA-approved for HER2-positive metastatic breast cancer after at least one prior treatment and available now. It is given as an IV infusion every three weeks. A serious lung side effect is a known risk and requires watchful monitoring. Ask your oncologist whether you qualify.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open breast cancer trials
A Study to Evaluate ARV-6723 Alone and With Pembrolizumab in Participants With Advanced Solid Tumors
This is a study to evaluate the safety and potential anti-tumor activity of an investigational drug called ARV-6723, in participants with advanced solid tumors. This is an open-label study which means that participants and study staff will know that all participants will receive ARV-6723. The investigational drug ARV-6723 will be given as an oral tablet on its own and also in combination with other drugs. Researchers think that ARV-6723 can help the body's immune system to better recognize, attack, and destroy cancer cells in adults with advanced solid tumors. ARV-6723 is an investigational drug, and this is the first time ARV-6723 will be used in humans. Depending on the treatment assignment, the investigational drug, ARV-6723, will be given as an oral tablet either on its own (monotherapy) or in combination with pembrolizumab, either through a vein (intravenously or IV) or through an injection beneath the skin (subcutaneously or SQ). This study will include multiple parts: In Part A1 (Phase 1a), different small groups of participants will receive lower to higher doses of ARV-6723 as monotherapy or in combination with standard-dose of pembrolizumab. In Part A2 (Phase 1b), two groups of participants with specific tumor indication(s) (TBD) will receive one of two doses selected based on information from Part A1. Details of Part B will be determined based on information generated from Part A.
ASHBY: Accelerated Super-Hypofractionated Breast Brachytherapy
The purpose of this study is to compare any good and bad effects of giving radiation treatment for breast cancer in 3 treatments over about 2 days.