Drug Development, Trial Design, and Endpoints in Oncology: Adapting to Rapidly Changing Science.

As a result of enhanced understanding of genetic and immunologic underpinnings of cancer, there has been progress in development of targeted and immunotherapies in oncology. The traditional linear sequential model of drug development has evolved. Early clinical trials of breakthrough therapies often include expansion cohorts, termed "seamless drug development." The US Food and Drug Administration (FDA) uses expedited programs, such as breakthrough designation and accelerated approval ensuring that transformative therapies are available to patients earlier in the cycle of evidence generation.