Adam Jacobs spoke next. Adam has a background in medical writing, but is also a statistician and sits on an ethics committee. His main point was that it’s never too early to ask a statistician.
Adam discussed military precision in writing protocols. The most important of these is to Keep It Simple. A protocol should be as simple as it should be and still achieve its objectives, for ease of implementation. Once an objective is selected, they must be maintained, with anything else being omitted. However, morale is also important, so its vital to keep key stakeholders informed, so that any problems can be identified early. Flexibility and contingency planning are also important, as is robust communication.
Adam went into communications in more detail, particularly for dealing with statisticians, who can seem to speak a different language to the rest of us! However, effective communication is vital. His top tip is that there is no substitute to face to face meetings. He said that statisticians are used to not being understood, and to explaining again if you let them know what you haven’t understood.
Adam described the statistician’s role: specification of objectives, trial design, analysis method, timing and choice of outcome methods and sample size. These are performed by the whole group, but led by the statistics.
Objectives are important to agree in detail as early as possible, particularly in later phase studies, and must be in a form that can be tested statistically.
Study design may be dictated by these objectives, but there are other elements that need to be considered (eg, blinded, parallel or crossover etc.) Methods must be carefully chosen to avoid bias; however these are not always possible in the real world, due to practical or ethical constraints. Compromises may need to be made to make the study achieveable, and this may require careful negotiation.
Selection of endpoints is largely a clinical decision, but statisticians can advise on freedom from bias and ease of analysis. This can also impact on sample size. Again, compromise might be required.
Analysis methods are mostly left to the statistician, but clinical input is still essential, as different analyses might be possible, and they might provide subtly different clinical information. Examples include repeated measures vs endpoint analysis, number of adverse events vs number of patients with events etc.
Again, even in sample size, many other non-statistical inputs are required, some of which might be subjective! This includes consideration of a ‘clinically relevant difference’, which has a significant impact on the sample size and needs to be discussed more widely. Sample sizes can be significantly more than imagined by non-statistians, which can raise budgetary issues.
Adam moved on to consider protocols from his perspective as an ethics committee statistician. He highlighted the importance of completing the ethics application form correctly, so it gives the committee the information it needs to review the study. The application form is the primary document, rather than the protocol, so don’t assume that the protocol will be read. Also, the committee contains lay members, so the application needs to explain some concepts in more detail than might be expected for medics alone.
When reviewing a protocol, Adam made particular mention of the sample size: too large is unethical (but rare, because of cost), and too small is also unethical as the study won’t answer the question! The committee needs to decide that the balance between risks and benefits involved with the study is acceptable. This depends on the scientific validity of the study.
Other common problems his ethics committee sees include: poorly written patient information sheets (in as much as 50% of cases!) including careful description of risky or unpleasant procedures, poorly explained methods, and inconsistencies in the application and between the application and the protocol.
In response to a question, Adam agreed that patient information sheets are getting longer. Certain elements are required by ICH GCP and templates are available from the NRES website. Adam suggested that a study summary would enable the patient to decide whether to read a more detailed subsequent description. However, some studies fall outside ICH GCP (eg, of a registered drug within its indication) a simpler approach would be beneficial.
Another question mentioned adaptive trials. Adam said that expert advice is a pre-requisite, but also suggested that checking assumptions of sample size midway through the study can be beneficial. This can be tested without breaking the blind, and Adam suggested we do this on any ongoing study; increasing the sample size mid-study could avoid a study failing to show a conclusive result.