Assessing tumor-related signs and symptoms to support cancer drug approval

Cancer causes premature death and significant, often devastating, symptoms. While prolongation of survival is an obvious end point for new cancer drug approval, the US Food and Drug Administration (FDA) has also utilized end points that evaluate patient symptoms. In this article we discuss the end points, evidence, and analyses supporting cancer drug approvals based on evaluations of tumor-related signs and symptoms. With advice from the Oncologic Drug Advisory Committee (ODAC) in the late 1970s and early 1980s, FDA determined that acceptable end points for cancer drug approval were survival or an improvement in the quality of a patient's life, e.g., an improvement in tumor-related symptoms. This article summarizes 15 FDA cancer drug approvals based on patient symptom assessments and/or physical signs (thought to represent symptomatic improvement) as the primary evidence of effectiveness. These include painful bone events (three cases), cosmetic improvement in Kaposi's sarcoma and cutaneous T-cell lymphoma (six cases), the consequences (decreased transfusions, etc.) of long-duration responses in leukemias and lymphomas (two cases), relief of pulmonary or esophageal obstruction (two cases), and one case each of symptom benefit in pancreatic cancer (also associated with survival benefit) and pulmonary symptom benefit in lung cancer. An instructive example of an individual patient benefit end point is discussed, though it did not lead to a drug approval (the cisplatin-epinephrine gel application). Improved trial designs and analysis plans may allow greater reliance on morbidity assessments to support future cancer drug approvals. Drug sponsors are encouraged to include symptom assessments in cancer clinical trials and to perform further research to improve symptom-assessment methods. The FDA routinely meets with sponsors at End of Phase 2 Meetings to discuss drug development plans and the design of phase 3 trials. We encourage sponsors to request special protocol assessments (SPA) after meeting with the FDA to get written confirmation of the adequacy of plans for assessing cancer morbidity and quality of life, including protocols, end points, statistical analysis plans, and draft case report forms.