Abemaciclib and Letrozole in Patients With Estrogen Receptor-positive Rare Ovarian Cancer

This study is testing a combination of two drugs — abemaciclib (a CDK4/6 inhibitor that slows cancer cell division) and letrozole (a hormone-blocking drug) — in people with rare, oestrogen receptor-positive ovarian cancers that are difficult to treat with standard chemotherapy. **You may be eligible if...** - You have been diagnosed with a rare, oestrogen receptor-positive ovarian cancer (specific subtypes apply) - You have received at least one prior line of treatment - You are using highly effective contraception if you could become pregnant - Your organ function meets the required levels **You may NOT be eligible if...** - Your ovarian cancer is not of the eligible rare subtype - You are pregnant or planning to become pregnant during the study - You have certain cardiovascular conditions or other serious medical problems - You have not recovered from side effects of previous cancer treatment Talk to your doctor to see if this trial is right for you.