Abemaciclib for the Treatment of Recurrent Ovarian or Endometrial Cancer

This study is testing abemaciclib — a drug that blocks specific proteins driving cancer cell growth — in patients with recurrent ovarian cancer or endometrial cancer whose tumors have specific genetic features. This "precision medicine" approach targets patients whose tumors are most likely to respond. **You may be eligible if:** - You have ovarian, fallopian tube, primary peritoneal, or endometrial cancer that has come back after treatment - For ovarian cancer: your tumor has been tested and shows CDK4/6 activation - For endometrial cancer: your tumor is endometrioid type, hormone receptor-positive, and does not have CCNE amplification or RB loss - You have received at least one prior chemotherapy regimen for recurrent disease - You have recovered from the side effects of your prior treatment - You are able to swallow oral medications - Your general health score (ECOG) is 0-2 **You may NOT be eligible if:** - Your tumor does not have the required molecular features - You have not yet had prior chemotherapy for recurrent disease - You have not recovered from chemotherapy or radiation side effects (still at grade 2+ except stable neuropathy) - You have serious organ dysfunction or active infections Talk to your doctor to see if this trial is right for you.