Regulatory and clinical consequences of negative confirmatory trials of accelerated approval cancer drugs: retrospective observational study

OBJECTIVES: To investigate the regulatory handling of cancer drugs that were granted accelerated approval by the US Food and Drug Administration (FDA) but failed to improve the primary endpoint in post-approval trials and to evaluate the extent to which negative post-approval trials changed the recommendations in treatment guidelines. DESIGN: Retrospective observational study. SETTING: FDA and National Comprehensive Cancer Network (NCCN) reports. INCLUDED DRUGS: Cancer drugs that received accelerated approval from the FDA and had negative post-approval trials. MAIN OUTCOME MEASURES: Regulatory outcomes, including withdrawal, conversion to regular approval, and no action. RESULTS: 18 indications for 10 cancer drugs that received accelerated approval but failed to improve the primary endpoint in post-approval trials were identified. Of these, 11 (61%) were voluntarily withdrawn by the manufacturer and one (bevacizumab for breast cancer) was revoked by the FDA. Of the 11 withdrawals, six occurred in 2021 alone. The remaining six (33%) indications remain on the label. The NCCN guidelines provide a high level of endorsement (category 1 endorsement for one and category 2A endorsement for seven) for accelerated approval drugs that have failed post-approval trials, sometimes even after the approval has been withdrawn or revoked. CONCLUSION: Cancer drug indications that received accelerated approval often remained on formal FDA approved drug labelling and continued to be recommended in clinical guidelines several years after statutorily required post-approval trials showed no improvement in the primary efficacy endpoint. Clinical guidelines should better align with the results of post-approval trials of cancer drugs that received accelerated approval.