Any Change or modification to the clinical protocol may be reported in a 5-day notice and they can be implemented if they do not affect:
a)validity of data or information resulting from the protocol
b)scientific soundness of the investigation plan
c)The rights,safety or welfare of the human subjects

And the changes that do not require any FDA approval are:
a)Change in study control
b)Change in method of estimation
c)Early termination of study
d)Reduction in sample size
e)Increasing the frequency at which data or information is gathered (subject follow up period)
f)Modifying the protocol to include additional patient observations and measurements
g)Modifying the inclusion/exclusion criteria to define target population