Latest data available from the United States Centers for Disease Control and Prevention (CDC) show that as of 2010, over 200,000 men and women were diagnosed with breast cancer in the U.S. The disease also remains to be one of the deadliest cancers particularly among women claiming the lives of more than 40,996 women and 439 men as of 2010.

An experimental breast cancer drug by Pfizer, one of the world's largest and most profitable pharmaceutical companies, has nonetheless hoped to extend the survival of patients diagnosed with breast cancer.

On Sunday, Pfizer announced that its experimental breast cancer drug known as palbociclib had encouraging results in an early clinical trial showing potentials in treating even advanced breast cancer cases.

Unlike other cancer treatments that are given intravenously, palbociclib is a pill that needs to be taken twice daily and while current medications can prevent breast cancer from worsening for 10.2 months, Pfizer said that that the PALOMA-1 study showed that palbociclib can prevent the disease from worsening for twice as long, a significant improvement.

The phase II trial, which involved 165 post-menopausal women with advanced breast cancer, showed that the subjects who received the experimental drug along with letrozole, a drug for treating breast cancer in women who have experienced menopause, had improved survival rates than women who only received letrozole. In women who were given both palbociclib and letrozole, their disease progressed only after 20.2 months compared to 10.2 months in those in the control group.

"These data demonstrate the potential of palbociclib to be a major advance in the treatment of women with this type of advanced breast cancer," said Mace Rothenberg, senior vice president of Clinical Development and Medical Affairs and chief medical officer for Pfizer Oncology. "We are proud to be at the forefront of research and development with respect to this promising new class of investigational anticancer agents and have initiated a broad clinical development program for palbociclib that includes breast and non-breast cancers."

Results of the study, which were presented at the annual meeting of the American Association for Cancer Research in San Diego on Sunday, also showed that the experimental drug can be safely used by women whose breast cancer had already spread to other parts of their body for a long period of time.

Study lead investigator Amita Patnaik, the associate director of clinical research at South Texas Accelerated Research Therapeutics in San Antonio said that although study participants experienced side effects such as nausea, vomiting and diarrhea, most of these were mild or moderate.