In a trial involving 165 patients, the experimental drug was preventing breast cancer for worsening for 20,2 months compared to 10.2 months delay obtained by the current known medication. Breast cancer is, unfortunately, the most common cancer to strike a woman. Earlier results, in laboratory tests, extended the hope of life for 18 months applying this new drug. Actually, a very important role to make the drug available for oncologists to use is treating their women patients will have the advice of the FDA. According to their rules, more clinical tests are needed. However, some precedents can be involved, the FDA has a very special attention for the potential drugs to help treating the cancer and some times they accelerate the approval for drugs promising good results. If this will happen in this case, Palbociclib will be in the medical arsenal on the next year. Palbociclib slows the proliferation of cancer cells by inhibiting CDK 4 and 6, two proteins involved in the cell division.