Palbociclib and Fulvestrant Improve Advanced Breast Cancer Survival Rates

By Kaitlyn D’Onofrio - Last Updated: March 26, 2025

Breast cancer patients who are not responding to endocrine therapy may benefit from combination palbociclib and pulvestrant therapy, new research suggests. 

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Patients with hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative advanced breast cancer (n = 521) were randomly assigned to receive palbociclib plus fulvestrant or placebo plus fulvestrant.  

In the palbociclib plus fulvestrant group, median overall survival was 34.9 months (95% confidence interval [CI], 28.8 to 40.0), compared with 28.0 months (95% CI, 23.6 to 34.6) in the placebo plus fulvestrant group (hazard ratio [HR] for death, 0.81; 95% CI, 0.64 to 1.03; P = 0.09; absolute difference, 6.9 months). Patients with endocrine therapy sensitivity (n = 410) receiving palbociclib had a mean overall survival of 39.7 months (95% CI, 34.8 to 45.7), compared with 29.7 months (95% CI, 23.8 to 37.9) in placebo patients with endocrine therapy sensitivity (HR, 0.72; 95% CI, 0.55 to 0.94; absolute difference, 10.0 months). Palbociclib patients’ median time to the receipt of chemotherapy was 17.6 months, compared with 8.8 months in the placebo cohort (HR, 0.58; 95% CI, 0.47 to 0.73; P < 0.001). 

“The results of the study show that it is possible to improve and prolong the life of patients with hormone receptor-positive metastatic breast cancer. We now have solid data to suggest that this treatment should be the new standard of care,” said study author Dr. Massimo Cristofanilli. 

Study author Nicholas Turner, a molecular oncology professor at The Institute of Cancer Research, London, and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, called the treatment’s development “one of the biggest advances in treatment for women with advanced breast cancer in the last two decades.” 

“It’s incredibly rewarding that the benefits we had previously seen for palbociclib are now translating into such significant extensions in survival,” said Turner. “This drug can offer women more precious time with their loved ones and because it is a targeted treatment it is much kinder than chemotherapy, and enables many women to carry on with their lives normally.” 

Dr. Cristofanilli, a hematology/oncology professor at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician, said, “Typically, treatments for estrogen-positive metastatic breast cancer delay the progression of cancer but almost never prolong the life of patients. This treatment is the first of its kind to show such an important benefit.” 

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Sources: NEJM, Medical Xpress, Northwestern Medicine

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