HQ Team
June 1, 2025: Merck & Co., Inc.’s drug Keytruda, along with Gilead Sciences Inc.’s antibody-drug conjugate, cut the risk of an aggressive breast cancer advancement and death by 35% during an end-stage trial.
Gilead’s Trodelvy and Keytruda combination was tried in 443 patients and compared with Keytruda along with chemotherapy as a first line of treatment in patients with inoperable locally advanced or metastatic triple-negative breast cancer, according to a Merck statement.
“A statistically significant and clinically meaningful improvement was observed with Keytruda plus Trodelvy, showing a 35% reduction in the risk of disease progression or death in the intent-to-treat population compared to Keytruda plus chemotherapy.”
Intent-to-Treat is a concept primarily used in clinical trials to include all randomised patients in the analysis, regardless of whether they completed the study or deviated from the protocol.
‘First-line options limited’
It is considered a more conservative approach to evaluating treatment effects because it accounts for real-world scenarios where patients may not adhere to the treatment plan perfectly.
“These results have the potential to be an important advancement for patients with PD-L1–positive metastatic triple-negative breast cancer, a population for whom first-line options remain limited,” said Sara Tolaney, MD, MPH, Dana-Farber Cancer Institute and primary investigator of the study.
“By combining sacituzumab govitecan (Trodelvy) with pembrolizumab (Keytruda), we’re seeing meaningful gains in progression-free survival and a promising trend in overall survival—findings that could support a new frontline standard of care for this aggressive disease,” she said in the statement.
More patients responded positively to the Keytruda and Trodelvy treatment (about 60%) compared to the Keytruda and chemotherapy (about 53%) treatment group.
Early signs
A complete disappearance of the cancer occurred in 13% of patients on Keytruda and Trodelvy, compared to 8% on Keytruda and chemotherapy. Patients on the Keytruda and Trodelvy treatment stayed in response longer — about 16.5 months versus 9.2 months for the other group.
There are early signs that patients on Keytruda and Trodelvy might live longer overall, but the data is still too new to be sure. Researchers will keep a close watch on this, according to the statement.
The companies also plan to share these results with regulatory authorities worldwide.
Merck is running several studies testing Keytruda with new drugs like Trodelvy in different types and stages of breast cancer. They have four major ongoing studies, two of which focus on advanced breast cancer that has spread.
“We’re committed to building on the established role of Keytruda as a foundational treatment for people with triple-negative breast cancer to provide new options in earlier lines of treatment, in the hope of improving outcomes for people living with this disease,” said Dr Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories.
These data support and give doctors another option to treat this disease, she said.
Detect and fight tumour
In 2021, Merck entered into a collaboration with Gilead to investigate Keytruda in combination with Trodelvy in an end-stage global trial.
Triple-negative breast cancer is the most aggressive type of breast cancer, which has the highest risk of recurrence within the first five years after diagnosis and is associated with worse outcomes compared to other forms of breast cancer.
Approximately 10-15% of patients with breast cancer are diagnosed with triple-negative breast cancer.
Keytruda therapy works by increasing the ability of the body’s immune system to help detect and fight tumour cells. There are currently more than 1,600 trials studying Keytruda across a wide variety of cancers and treatment settings.
