Why Has a Run-In Period Been a Design Element in Most Landmark Clinical Trials? Analysis of the Critical Role of Run-In Periods in Drug Development

Milton Packer

Research output: Contribution to journalArticle

4 Scopus citations


Prior exposure to one of the randomized treatments has been a routine design element of large-scale trials in patients at high cardiovascular risk. A run-in feature has allowed our trials to be more realistic; it has strengthened their ability to estimate the true treatment effect; and it has never undermined the validity of a trial's findings. Those who suggest that run-in periods distort the results of large-scale trials should become more familiar with our history of drug development and our standards of clinical practice. Physicians use run-in periods every day in real life, and trialists have used run-in periods for decades to reliably establish the role of new cardiovascular drugs. Those who reflexively criticize the trials because of their inclusion of a run-in period need to carefully reexamine how medicine is practiced and how it advances.

Original languageEnglish (US)
Pages (from-to)697-699
Number of pages3
JournalJournal of Cardiac Failure
Issue number9
StatePublished - Sep 1 2017



  • Clinical trial design
  • drug efficacy studies
  • heart failure trials
  • run-in periods

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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