Access with evidence development: the US experience.

The concept of access with evidence development (AED), also known as 'coverage with evidence development' in the Medicare programme, has long been discussed as a policy option for ensuring more appropriate use of new technologies in the US. This article provides a comprehensive overview of more than 10 years of US experience with AED, both in the public and private healthcare sectors. Beginning with a discussion of the successes of private plans' conditional coverage for high-density chemotherapy for autologous bone marrow transplants for metastatic breast cancer and Medicare's conditional coverage of lung-volume-reduction surgery in the 1990s, the article moves on to describe how Medicare worked to codify AED as one of its coverage policy options in the early part of this decade. More recent private and public sector initiatives are also discussed, including an overview of barriers to implementing AED. Despite the complexity of political, financial and ethical issues faced in implementation, AED is now a permanent fixture of US coverage policy. Future initiatives within the Medicare programme and with private payers in the US are much more likely to succeed by relying upon the simple but consequential principles laid out at a Summit convened in Banff, Alberta, Canada in 2009 and presented in another article in this issue.