Earlier, Pfizer's breast cancer drug Ibrance's clinical trial was delayed due to some issues based on the independent Data Monitoring Committee's (DMC) assessment. After the issues have been resolved, the clinical trial of the drug were resumed.

Ibrance, also known as palbociclib, is Pfizer's experimental breast cancer drug. It is undergoing phase 3 study called PALOMA-3 trial. The drug has met its primary ends and showed improvements in Progression-Free Survival of PFS, according to reports.

The drug, Ibrance, was used in combination with British multinational pharmaceutical company AstraZeneca Plc's Faslodex or fulvestrant, which is an effective drug to block estrogen. According to the reports, the trail was successful. Patients were asked to take the combination of the two drugs. The reports stated that results of the trial were far better than the patients who were taking fulvestrant alone.

The reports stated that the study had enrolled those patients whose breast cancer had estrogen-receptor positive and human epidermal growth factor receptor 2-negative.

Dr. Mace Rothenberg, chief medical officer for Pfizer Oncology and senior vice president of Clinical Development and Medical Affairs, 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".

While talking about the new drug, Chris Schott, a JPMorgan Chase & Co. analyst, said the new drug has the potential to turn into a blockbuster drug. According to Schott, successful clinical trial could give an edge to the drug. Analysts predicted that the new breast cancer drug could help the company to make $5B in revenue.

There are number of companies that have been working to develop a drug that could be helpful in blocking cyclin-dependent kinase 4 and 6, which could be an effective treatment for breast cancer.