The challenge of achieving target drug concentrations in clinical trials: experience from the Symphony study.
BACKGROUND: The Symphony study compared four immunosuppressant regimens, defined by protocol-specified target drug concentrations. This subanalysis examines actual drug levels and the implications on the interpretation of results. METHODS: De novo renal transplant patients (n=1645) were randomized to receive mycophenolate mofetil (2 g/day) and corticosteroids in combination with standard-dose cycl