Reporting harms more transparently in trials of cancer drugs

The clinical trial report of ribociclib, a drug for breast cancer, mentions in its discussion that “Most patients had an acceptable adverse-event profile.”1 A report of a trial of liposomal irinotecan in pancreatic cancer states in the concluding paragraph that it “has a manageable and mostly reversible safety profile.”2 And a trial of tasquinimod in patients with prostate cancer reports “the tolerability was good overall.”3

All three of these studies were published in top medical journals. Naturally, readers would take these statements to be true. However, a look at the data for adverse events doesn’t paint as good a picture. In the first study, more than twice as many patients in the ribociclib arm as in the control arm experienced severe (grade 3 or higher) adverse events (271/334 v 108/330).1 The difference in treatment related serious adverse events (leading to death, life threatening condition, hospital admission or prolonged admission, disability or permanent damage, congenital anomaly or birth defect, or that required medical or surgical intervention to prevent one of the other outcomes4) was nearly five times higher (25 v 5). The trial of liposomal irinotecan that mentioned “manageable and mostly reversible” toxicities in fact shows that five patients in the intervention arm died from drug toxicities versus none in the control.2 In the trial reporting overall good tolerability of tasquinimod, the incidences of severe and serious adverse events compared with control were 42.8% v 33.6% and 36.0% v 23.6%, respectively.3

These three studies are only representative examples. The adverse event profiles of many new cancer drugs are hidden behind similarly general or subjective terms that obscure their harms. We …