The international landscape of medical research is in the midst of a process of diversification and change. The randomized controlled trial (RCT), long considered the global gold standard for clinical research, has become increasingly contested and is partly replaced by alternative methodologies, standards and forms of evidence. The contours of mainstream medical research are changing as a result. Regulatory paradigms and standards are, literally, being rewritten, at a global level. The evidence-based medicine (EBM) hierarchy of evidence is redefined. This special issue explores these developments through the concept of 'alter-standardization'. The term refers to the processes, controversies and negotiations through which multiphase RCTs and the EBM system are challenged and gradually superseded by alternative methodological and regulatory forms and standards. This special issue examines the conceptual, practical and theoretical implications of these changes, and the ways in which these transformations influence the situation and possibilities of patients, knowledge producers, physicians, large pharmaceutical corporations, smaller biotech companies, as well as regulatory bodies, civil societal organizations and national health care systems. The articles in this special issue make use of comparative and historical perspectives that focus on scientific, social, economic and regulatory developments in the European Union, China, India, Japan, Argentina, the UK and the USA. They show that the alter-standardizing of clinical trials arises in a pluralistic way, that is driven by a variety of often conflicting factors, developments and expectations. These changes reflect a broad transformation in the culture and politics of biomedicine today, with implications for the ways in which new medicinal products, devices, procedures and technologies are developed, approved for clinical use, sold to consumers, and licensed by health care systems.