Statistical issues related to early closure of STOP-ROP, a group-sequential trial.
The Supplemental Therapeutic Oxygen for Prethreshold Retinopathy of Prematurity trial used the group-sequential alpha-spending approach with asymmetrical tails to investigate whether supplemental oxygen therapy would reduce the proportion of infants progressing from prethreshold retinopathy of prematurity (ROP) to threshold ROP from 30% to 20%. Three years of enrollment were predicted. After 4 years, the data and safety monitoring committee (DSMC), faced with a projected delay of 2-3 more years, opted to terminate the trial after 1 further year of enrollment despite a continually borderline test statistic. We discuss factors relating to the DSMC decision and its effect upon the conclusions that may be drawn from the trial.
Oden
Neal L
NL
The EMMES Corporation, Rockville, MD 20850, USA. noden@emmes.com
Phelps
Dale L
DL
D026661:Clinical Trials Data Monitoring Committees; D003627:Data Interpretation, Statistical; D018450:Disease Progression; D006801:Humans; D007231:Infant, Newborn; D010102:Oxygen Inhalation Therapy; D016032:Randomized Controlled Trials as Topic / Q000592:standards / Q000706:statistics & numerical data*; D012178:Retinopathy of Prematurity / Q000517:prevention & control*