The SPA doesn't seem like it's anything out of the ordinary. I expect CTIX SPA will be to ensure the ability to establish an efficacy claim as a result of the phase 3 trial. The SPA will ensure that the protocol followed during the trial will produce evidence that the FDA can use to approve the drug. I found an FDA document that spells it out fairly well.

http://web.archive.org/web/20041117222710/htt...otocol.pdf