When an IRB approves a study, continuing review should be performed at least annually. All the records listed in 21 CFR 56.115(a)(1)-(4) are required to be maintained. The clock starts on the date of approval, whether or not subjects have been enrolled. Written progress reports should be received from the clinical investigator for all studies that are in approved status prior to the date of expiration of IRB approval. If subjects were never enrolled, the clinical investigator's progress report would be brief. Such studies may receive continuing IRB review using expedited procedures. If the study is finally canceled without subject enrollment, records should be maintained for at least three years after cancellation.