It is crucial to ensure the safety and integrity of
individual
patients participating in the trial. As such, accruing data
should be monitored for any evidence of adverse events. It is
important that this monitoring of accruing data is undertaken by
individuals who are independent of the trial team as knowledge of the
unblinded data or emerging trends may make
the
investigator in charge of patient recruitment reluctant to enroll new
patients
or to continue treating those already enrolled if the data suggests one
intervention
is better than the other.
A Data Monitoring Committee (DMC) should be established and
meet regularly to give
independent advice on whether the trial should a) continue as
planned b)
stop further recruitment or c) discontinue the intervention if there
is
evidence that the latter is substantially better (or worse) than the
alternatives.
Sometimes it is recommended that the intervention be modified (e.g.
treatment
dosage reduced or one treatment arm stopped in a multiple arm
trial).
Such data and safety monitoring committees often use statistical
stopping
rules to help with their decision making.
If possible, the Data Monitoring Committee should meet early in the course of the trial in order that they can discuss the protocol, the trial, any analysis plan, future meetings, and to have the opportunity to clarify any aspects with the principal investigators (Damocles, 2005). It is important that the committee meets within one year of recruitment commencing.