IRBs, at least the one I serve on, don't typically

IRBs, at least the one I serve on, don't typically get all the unblinded data from a study. They just get DSMB reports (usually, continue study as planned), and review them on periodic basis (typically >95% of the time this is once a year). They do get promptly notified of unexpected SAEs related to study drug in real time, or unusual DSMB meetings or any new information or guidance that would change the study risk vs. benefits calculation. There would be no reason for IRB to ask for raw unblinded data, as the DSMB already reviewed everything and decided trial should continue as planned, with recommendation for slight modification - to do another interim analysis at 75% with mortality at 6 weeks instead of 4 weeks.