Table 3 Amendment changes mentioned by interviewees along with the number that had mentioned each

Addition of sites

4

Change of PI

4

Change to eligibility criteria^a

4

Change to PIS wording

4

Change to protocol

3

Extension of study

3

Sub-studies (inc. COVID)^a

3

Typo changes

3

Change to advertisement material

2

Changes to Reference Safety Information (RSI) safety data^a

2

Increase in sample size

2

Related to trial drug^a

2

Adding additional data

1

Adding clarifications

1

Adding extra visits

1

Addition of arms in drug trials^a

1

Additional procedures^a

1

Additional safety procedures^a

1

Additional visits^a

1

Allow contact of patient prior to appointment

1

Change from specific to generic wording

1

Change of post-dose observational follow-up time^a

1

Change of questionnaire wording

1

Change to data collection tools^a

1

Change to design and trial flow

1

Change to patient communication methods (inc. due to COVID)

1

Change to statistical analysis plans^a

1

Changes to intervention^a

1

Changes to recruitment process

1

Changing Serious Adverse Events (SAE) process and definitions

1

Collecting additional samples

1

End of recruitment date change

1

Making wording more suitable for laypeople

1

Taking off hold (inc. due to COVID)

1