Engaging with the Institute for Clinical and Economic Review (ICER), a health technology assessment organization located in the USA, can pose a challenge for drug manufacturers. Drug manufacturers can engage with ICER by providing information and feedback at several points during ICER’s assessment process. Engagement offers drug manufacturers an opportunity to help ensure that ICER’s assessments reflect all available science and input, and to respond to the organization’s draft reports before they reach their final form. However, some may see it as legitimizing potentially controversial findings from ICER about a drug’s value. To our knowledge, however, no formal investigation has pursued this question. We undertook an empirical analysis to understand how often manufacturers engage with ICER and whether engagement may influence ICER’s cost-effectiveness estimates.