89 Background: The low trial publication rate for drugs approved by the U.S. Food and Drug Administration (FDA) and the discrepancies between data submitted to the FDA and data found in published trials remain concerning. We investigated the publication statuses of trials of recently approved anticancer drugs documented by the FDA, especially immune checkpoint inhibitors (ICPis), to determine the discrepancies between data submitted to the FDA and those published. Methods: We identified all ICPis approved between 2011 (the year the first ICPi was approved by the FDA) and 2014 (selected to assure a follow-up of at least 3 years post-approval). We assessed the clinical trials for each drug indication and matched each trial with publications in the literature. The primary outcome was the publication status 2 years post-approval. We examined the association between time to publication and drug type using a multilevel Cox regression model, adjusted for clustering within drug indications and individual covariates. Results: Between 2011 and 2014, 36 anticancer drugs including 3 ICPis were newly approved by the FDA. Of 19 trials investigating the 3 ICPis, 11 (58%) were published within 2 years post-approval. We randomly selected 10 of the 33 remaining anticancer drugs; 68 of 101 trials investigating these drugs (67%) were published. Overall, the publication rate was 66% at 2 years post-approval with a median time to publication of 2.3 years. There was no significant difference in time to trial publication between ICPis and other anticancer drugs (adjusted hazard ratio [HR], 1.1; 95% confidence interval [CI], 0.8–1.7; P = 0.55); however, non-ICPIs investigated specifically in randomized phase 2 or 3 trials were significantly more likely to be published earlier than ICPis (adjusted HR, 7.4; 95% CI, 1.8–29.5; P = 0.005). Conclusions: One in three trials of the newest anticancer drugs remained unpublished 2 years after FDA approval. The ICPi publication rate was similar to that of other anticancer drugs. (Protocol registration: UMIN000030475).