Pfizer’s newly approved breast cancer treatment Ibrance has improved survival in certain patients when used with another oncology drug.
The US firm said that in its Paloma-3 trial Ibrance (palbociclib) met its primary endpoint of demonstrating an improvement in progression-free survival (PFS) when used with AstraZeneca’s Faslodex (fulvestrant).
This is when compared with AZ’s drug and placebo in women with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer following disease progression during or after endocrine therapy.
The study was stopped early due to efficacy based on an assessment by an independent Data Monitoring Committee.
The dug is believed to be worth around $3 – $5bn a year at its peak – with some analysts even predicting sales of $10bn, should it gain additional licences.
These are the first randomised phase 3 trial results for Ibrance, a new anti-cancer medicine with the new mechanism of cyclin-dependent kinase 4/6 (CDK 4/6) inhibition.
Ibrance was approved by the FDA in February as a first-line treatment for women with advanced or metastatic estrogen receptor positive, human epidermal growth factor receptor 2 negative (ER+/HER2-) breast cancer.
The drug was fast-tracked through the regulatory process with the FDA asking for more data as it becomes available.
The accelerated approval was based on results of a study that showed Ibrance delayed progression of disease significantly longer than Novartis’ aromatase inhibitor Femara (letrozol).
Dr Mace Rothenberg, senior VP of clinical development and medical affairs and chief medical officer for Pfizer Oncology, said: “The results of this trial are especially important because they help us understand the potential of Ibrance to improve outcomes in patients with this difficult to treat cancer.
“We’re gratified to be able to stop the trial early and are engaging in discussions with health authorities regarding a regulatory path forward.”
Pfizer said in a statement that more detailed efficacy and safety results from Paloma-3 would be published at the American Society of Clinical Oncology (ASCO) 2015 meeting in the summer.