New drugs, particularly those belonging to novel drug classes, can dramatically improve clinical outcomes but may also lead to serious toxicities. Given an emphasis on disease outcomes, drug-related toxicities may go unrecognized for years. Delayed toxicity recognition in rapidly adopted drugs can impede clinicians’ ability to weigh potential drug benefits against harms and lead to unintended patient harm.10 A 2016 National Cancer Policy Forum workshop on drug development emphasized balancing the benefits and harms of new drugs, noting that poor knowledge of adverse events limits risk-benefit modeling.

Our search identified 325 studies; we extracted data from 20 studies representing 15 RCTs. Most trials (n = 15) reported adverse events using MedDRA. The number of descriptive terms ranged from eight for thyroiditis to 24 for colitis. For dermatitis, all trials reported pruritus (n = 15); most reported rash (n = 14). For hepatitis and thyroiditis, 14 trials reported at least one adverse event term, most often a diagnosis or test result. 

In conclusion, novel drug classes have the potential to dramatically improve outcomes in patients with cancer, but rapid understanding of their toxicities is critical. Although ClinicalTrials.gov has the potential to facilitate more complete understanding of toxicities, the wide-ranging terminology in current use impedes transparency and possibly patient safety. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5812307/