Summary of main findings
Ninety per cent of the 89 respondents across all four surveys whose external pilot trial had completed stated that their pilot trial was either feasible (42/89, 47%) or feasible with changes to the trial design (38/89, 43%), yet only two-thirds reported the intention to conduct a future definitive trial (59/89, 66%). This suggests that just under one quarter (21/89, 24%) of respondents who considered their external pilot trial to be feasible (or feasible with changes) did not intend to conduct a definitive trial. Respondents described varied barriers to external pilot trial progression, with the availability of funding for a future definitive trial and changing priorities of the CI most common.