A tutorial on pilot studies: the what, why and how

TLDR

Pilot studies for phase III trials, also called feasibility or vanguard studies, are routinely conducted to assess safety, recruitment potential, multicentre feasibility, and to build clinical experience, serving as an essential prerequisite that enhances the likelihood of success and helps avoid failed full‑scale studies. This paper aims to provide a comprehensive examination of pilot studies for phase III trials, covering their rationale, relationships to proof‑of‑concept and adaptive designs, common challenges, success criteria, FAQs, ethical considerations, and guidance on reporting with CONSORT. The authors systematically review pilot study components, outlining reasons for conducting pilots, their links to proof‑of‑concept and adaptive designs, common misconceptions, success criteria, FAQs, ethical issues, and CONSORT reporting recommendations.

Abstract

Pilot studies for phase III trials - which are comparative randomized trials designed to provide preliminary evidence on the clinical efficacy of a drug or intervention - are routinely performed in many clinical areas. Also commonly know as "feasibility" or "vanguard" studies, they are designed to assess the safety of treatment or interventions; to assess recruitment potential; to assess the feasibility of international collaboration or coordination for multicentre trials; to increase clinical experience with the study medication or intervention for the phase III trials. They are the best way to assess feasibility of a large, expensive full-scale study, and in fact are an almost essential pre-requisite. Conducting a pilot prior to the main study can enhance the likelihood of success of the main study and potentially help to avoid doomed main studies. The objective of this paper is to provide a detailed examination of the key aspects of pilot studies for phase III trials including: 1) the general reasons for conducting a pilot study; 2) the relationships between pilot studies, proof-of-concept studies, and adaptive designs; 3) the challenges of and misconceptions about pilot studies; 4) the criteria for evaluating the success of a pilot study; 5) frequently asked questions about pilot studies; 7) some ethical aspects related to pilot studies; and 8) some suggestions on how to report the results of pilot investigations using the CONSORT format.