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Purpose Modifications in cancer drug indications, dosing, and related toxicities after Food and Drug Administration approval are common. It is unclear whether drug approval without a supporting randomized controlled trial (RCT) influences the probability of such modifications. Methods We searched the Drugs@FDA Web site for new drug indications for solid tumors approved between January 2006 and December 2016. Study characteristics, regulatory pathways, and label modifications from approval to October 2017 were collected from drug labels. Label modifications were considered to be major if defined as such in the drug label. Indications approved with and without supporting RCTs were compared using logistic regression. The Benjamini-Hochberg false discovery rate method was used to adjust for multiplicity. Results We identified 59 individual drugs for 109 solid tumor indications. Of these, 17 indications (15.6%) were not supported by an RCT, with no change over time. Indications not supported by RCTs were more likely to require companion diagnostic tests (odds ratio [OR], 3.90; P = .02), to include surrogate end points as primary outcomes (OR, 7.88; P < .001), and to receive breakthrough therapy designation (OR, 7.62; P = .006) or accelerated approval (OR, 17.67; P < .001). Indications not supported by RCTs were associated with significantly higher odds of postapproval modifications in common adverse events (71% v 29%; OR, 5.78; P = .002). A nonsignificantly higher odds of postapproval major modifications in warnings and precautions was also observed (88% v 62%; OR, 4.61; P = .051). Postapproval major modifications in indication and usage, dosing and administration, boxed warnings, and contraindications were comparable in the two groups. Conclusion Cancer drug indications not supported initially by RCTs are associated with more postmarketing safety-related label modifications. Health care professionals should be vigilant for unrecognized adverse effects when prescribing drugs approved without a supporting RCT.

Purpose Clinical practice guidelines (CPGs) and consensus statements (CSs) are used to apply evidence-based medicine or expert recommendations to clinical practice. Here we explore author financial conflicts of interest (FCOIs), sources of guideline funding, and their relationship with endorsement of specific drugs. Methods An electronic search of MEDLINE was conducted to identify CPGs and CSs for common solid cancers published between January 2003 and October 2013. The search was restricted to articles evaluating systemic therapy. We extracted data on self-reported author FCOIs, funding sources, use of manuscript writers, and endorsement of specific drugs in the abstract of the article. Results Of 142 articles evaluated, 64% were CPGs, and 36% were CSs. The proportion of articles reporting FCOIs improved from 11% in 2003 to 93% in 2013 (P for trend < .001). Only 45% of articles explicitly reported funding sources. Of these, 65% disclosed partial or full industry sponsorship. Use of manuscript writers was declared in 13%, but many articles did not explicitly report the role of authors in the writing of the manuscript. Endorsement of specific drugs was significantly associated with author FCOIs (odds ratio [OR], 7.29; P = .001), but not with industry funding (OR, 0.95; P = .37). Conclusion Reporting of FCOIs in CPGs and CSs has improved over time. Despite prevalent funding of guideline development by industry, such funding is not associated with endorsement of specific drugs. Author FCOIs are prevalent, and endorsement of a specific drug seems to be more common when authors have FCOIs with the pharmaceutical company marketing that drug.