- Patients of childbearing / reproductive potential should use adequate birth control measures, as defined by the investigator, during the study treatment period and from screening to 90 days after the last dose of durvalumab monotherapy or 180 days after the last dose of durvalumab + tremelimumab combination. A highly effective method of birth control is defined as a method which results in a low failure rate (i.e. less than 1% per year) when used consistently and correctly. Such methods include: