Pfizer has revealed new data from the PALOMA-3 trial, a Phase lll study that evaluated Ibrance (palbociclib) in combination with fulvestrant compared to placebo plus fulvestrant for the treatment of women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer.
The trial enrolled HR+/HER2- metastatic breast cancer patients whose disease progressed after prior endocrine therapy.
Results of the trial showed that a positive trend in the overall survival in certain patients, which is the secondary goal, but this trend did not reach statistical significance.
Pfizer Global Product Development Oncology chief development officer Mace Rothenberg said: “While the difference in overall survival narrowly missed the threshold for statistical significance – a high bar for any trial in this patient population – it is similar, in absolute terms, to the improvement in median progression-free survival previously demonstrated in this trial.
“Ibrance in combination with endocrine therapy has transformed the treatment landscape for patients with HR+/HER2- metastatic breast cancer.”
The PALOMA-3 trial met its primary goal of progression-free survival (PFS) at a previous interim analysis, and showed a statistically significant and clinically meaningful improvement in PFS for the Ibrance combination.
Based on the PFS results of the PALOMA-3 trial, the Ibrance and fulvestrant combination has been approved for use in the treatment of HR+/HER2- metastatic breast cancer in more than 80 countries worldwide.
PALOMA-3 trial principal investigator Nicholas Turner said: “The duration of the survival in hormone receptor-positive metastatic breast cancer patients, and the potential for subsequent therapies to confound overall survival outcomes, make demonstrating statistically significant improvement in overall survival extremely difficult.
“The results from this overall survival analysis support the strong progression-free survival results from PALOMA-3 and, while not statistically significant, are encouraging for physicians and patients.”
Ibrance is an oral inhibitor of cyclin-dependent kinases (CDKs) 4 and 6, 3, which are major regulators of the cell cycle that cause cellular progression.