Phase I Study of Olaparib and Temozolomide for Ewings Sarcoma or Rhabdoomyosarcoma

This research study is a Three arm Phase I clinical trial, which tests the safety of an investigational drug or combination of drugs and also tries to define the appropriate dose of the combination of investigational drugs to use for further studies. "Investigational" means that the combination of drugs is being studied. It also means that the FDA has not yet approved the combination of drugs for your type of cancer. Olaparib works by blocking the activity of a protein called poly (ADP-ribose) polymerase (PARP) which is involved in DNA repair. Cancer cells rely on PARP to repair their DNA and enable them to continue dividing. Olaparib has been used in research studies with other cancers. Information from those other research studies suggests that this drug may help to treat patients with Ewing's sarcoma. The investigational drug olaparib is not approved for any use outside of research studies. Temozolomide (Temodar) is approved by the FDA for the treatment of a type of brain tumor, glioblastoma. It has been studied in Ewing sarcoma in previous research studies. While it is not approved by the FDA for Ewing sarcoma, it is considered part of standard treatment for relapsed disease. Irinotecan is approved by the FDA for the treatment of gastrointestinal cancers. It has been studied in Ewing sarcoma in previous research studies. While it is not approved by the FDA for Ewing sarcoma, it is considered part of standard treatment for relapsed disease. Laboratory studies suggest that the combination of olaparib and temozolomide and/or irinotecan may help kill Ewing sarcoma or rhabdomyosarcoma cells. In this research study, the investigators are looking for the highest dose of the combination of olaparib and irinotecan and/or temozolomide that can be given safely. The investigators will also begin to collect information about the effects of the combination on Ewing sarcoma and rhabdomyosarcoma.