Novel innovative drugs have improved disease control, survival and quality of life for many patients. The costs of these drugs, however, are extremely high and threaten the long-term affordability of our health care system. Efficient use of existing drugs can decrease drug expenditure whilst improving patients' quality of life at the same time. Efficiency adjustments should not compromise treatment efficacy and therefore, clinical research on the matter is crucial. In this article, we demonstrate that efficiency research is feasible, as exemplified by the SONIA study. We make the case for a 'revolving fund' in which savings from one study are used to fund a next one. A revolving fund thus stimulates efficiency research and capitalizes research investments in the interest of both patients and society.