SPA – Special Protocol Assessment. An SPA is a declaration by the FDA that an uncompleted, phase 3 study would be acceptable for approval. The acceptability relates to the study itself rather than results. So it includes study design, endpoints used, statistical analyses used. The company running the study requests an SPA before the study starts. This gives them confidence that the study’s design will not be an issue when the drug comes up fr approval.
From the FDA PDUFA goals:
Three types of protocols related to PDUFA products are eligible for this special protocol assessment under the PDUFA goals:
(1) animal carcinogenicity protocols,
(2) final product stability protocols,
(3) clinical protocols for phase 3 trials whose data will form the primary basis for an efficacy claim. The clinical protocols for phase 3 trials can relate to efficacy claims that will be part of an original new drug application (NDA) or biologics license application (BLA) or that will be part of an efficacy supplement to an approved NDA or BLA.