Primary Causes of Death Reported to the FDA Suggest Less Ticagrelor Mortality Benefit than the List Issued to the PLATO Trial Investigators.

Background: The PLATO trial data set reported to the FDA (DRFDA) revealed that some primary deaths causes (PDC) were inaccurately reported favoring ticagrelor. Trial Investigators (DRTI) received different data set with more ticagrelor mortality advantage. We compared these two death lists for the match in PDC. Methods and Results: The DRFDA contains 938 deaths, while the DRTI contains 905. We matched "vascular", "non-vascular", "unknown", "missed", and "other" causes of death between DRFDA and DRTI. The DRFDA used 14 vascular, 9 non-vascular, 1 unknown and 1 other PDC codes, while the DRTI used 14 but different vascular, 14 non-vascular but no unknown or other PDC codes. We observed a significant mismatch for the PDC codes between the DRFDA and DRTI data sets. Most DRFDA deaths were vascular (n = 677), fewer non-vascular (n = 159) and unexpectedly many unknown (n = 95) or other (n = 7) PDC. Surprisingly, the shorter DRTI contains more vascular (n = 795), fewer non-vascular (n = 110), but no unknown, other, or missed causes. There were more sudden deaths in DRTI than in DRFDA (161 vs. 138; p < 0.03), twice as many post-myocardial infarction deaths (373 vs. 178; p < 0.001) but fewer heart failure deaths (73 vs. 109; p = 0.02). The reported non-vascular PDC match better except for 2 extra suicides in the clopidogrel arm of the DRTI. Conclusions: Over 100 "unknown", "missed", or "other" PDC events reported by the trial sponsor to the FDA were omitted from the investigator data set contributing to the inflated differences in vascular mortality benefit of ticagrelor reported in numerous PLATO publications. Synchronization of PDC reporting between regulatory agencies and investigators was lacking in PLATO but remains mandatory to ensure quality for future indication-seeking trials.

Impact of the reporting source on Platelet Inhibition and Treatment Outcomes (PLATO) trial deaths.

BACKGROUND: Platelet Inhibition and Clinical Outcomes (PLATO) was a multicenter, randomized double-blind trial assessing efficacy and safety of ticagrelor versus clopidogrel in patients with acute coronary syndrome. The reported mortality benefit of ticagrelor in the PLATO trial has been challenged for over decade, and never confirmed in later trials. OBJECTIVE: To compare if there were any differences when deaths were reported to the FDAby the sponsors or by independent Contract Research Organizations (CRO). METHODS: We obtained the complete PLATO deaths dataset reported to the FDA and revealed that some events were inaccurately reported favoring ticagrelor. The entire FDA list contains precisely detailed 938 PLATO deaths. The CRO reported outcomes from the USA, Russia, Georgia, and most of Ukraine, while sites in 39 other countries were controlled by the trial sponsors. We compared vascular- (code "11"), non-vascular- (code "12"), and unknown (code "97") deaths triaged by the reporting source. RESULTS: Overall, most PLATO deaths were vascular (n=677), less non-vascular (n=159) andunexpectedly many of "other" (n=7) or "unknown" (n=95) origin reported either by sponsors (n=807) or CRO (n=131). The trial sponsors reported more clopidogrel deaths from vascular (313 vs.239), non-vascular (86 vs.58) and unknown (53 vs. 26) causes.In contrast, CRO-monitored sites reported significantly (72 vs. 53; p<0.01) more ticagrelordeaths than after clopidogrel from vascular (51 vs.39), non-vascular (8 vs.7) and unknown (10 vs. 4) causes. CONCLUSION: Deaths were reported differently by sponsors and CRO within the same trial. Since some deaths were misreported by PLATO sponsors, only the CRO data seems mostly reliable. Among all countries, the CRO - reported PLATO-USA outcomes represent the largest and most realistic dataset of realistic evidence suggesting ticagrelor inferiority to clopidogrel for all primary endpoint components including vascular death.