CCDM Clinical Trial Design 3 — Questions and Answers
Question 1: What is the role of a Data Safety Monitoring Board (DSMB) in clinical trial design?
- To write the statistical analysis plan before the trial starts
- To independently review accumulating safety and efficacy data and recommend trial continuation, modification, or termination (Correct answer)
- To audit site data entry for completeness
- To approve the final clinical study report
Correct answer: To independently review accumulating safety and efficacy data and recommend trial continuation, modification, or termination
A DSMB is an independent committee that periodically reviews unblinded interim data to protect participant safety and ensure ongoing trial integrity.
Question 2: In a stratified randomization scheme, stratification variables are chosen primarily to:
- Increase the overall sample size
- Ensure balance of key prognostic factors across treatment groups (Correct answer)
- Simplify the informed consent process
- Reduce the number of endpoints required
Correct answer: Ensure balance of key prognostic factors across treatment groups
Stratification ensures that important prognostic factors (e.g., disease severity, age group) are balanced between treatment arms, reducing confounding.
Question 3: Which endpoint type is defined as a direct measure of how a patient feels, functions, or survives?
- Surrogate endpoint
- Pharmacokinetic endpoint
- Clinical endpoint (Correct answer)
- Biomarker endpoint
Correct answer: Clinical endpoint
Clinical endpoints directly measure patient outcomes meaningful to patients and clinicians, such as survival, symptom relief, or functional status.
Question 4: In the context of clinical trial design, what is a 'run-in period'?
- The period after final patient enrollment
- A pre-randomization phase used to assess eligibility, compliance, or baseline response (Correct answer)
- The time between last patient visit and database lock
- An unblinded pilot phase before pivotal trial initiation
Correct answer: A pre-randomization phase used to assess eligibility, compliance, or baseline response
A run-in period precedes randomization and is used to evaluate patient suitability, wash out prior medications, or assess baseline compliance.
Question 5: A Bayesian adaptive design differs from a frequentist design primarily in that it:
- Uses only historical data with no prospective enrollment
- Incorporates prior probabilities and updates them with accumulating trial data (Correct answer)
- Requires a larger sample size by regulatory mandate
- Eliminates the need for a control arm
Correct answer: Incorporates prior probabilities and updates them with accumulating trial data
Bayesian designs update prior probability distributions with incoming trial data to produce posterior probabilities, enabling more flexible interim decision-making.
Question 6: Which of the following best describes an 'umbrella trial' design?
- A single intervention tested across multiple diseases simultaneously
- Multiple targeted therapies tested within a single disease based on biomarker subgroups (Correct answer)
- A two-arm trial using an umbrella as a placebo device
- A trial with a single biomarker tested across multiple endpoints
Correct answer: Multiple targeted therapies tested within a single disease based on biomarker subgroups
Umbrella trials test multiple targeted treatments within a single cancer type, assigning patients to therapy arms based on their specific molecular biomarker profile.
Question 7: What is the primary difference between 'intention-to-treat' (ITT) and 'per-protocol' (PP) analysis populations?
- ITT excludes all dropouts; PP includes all randomized patients
- ITT analyzes all randomized patients regardless of compliance; PP analyzes only patients who completed treatment per protocol (Correct answer)
- ITT is used only for safety; PP is used only for efficacy
- ITT is required for Phase I; PP is required for Phase III
Correct answer: ITT analyzes all randomized patients regardless of compliance; PP analyzes only patients who completed treatment per protocol
ITT preserves the benefits of randomization by including all randomized patients in their assigned groups, while PP analysis may introduce selection bias by excluding non-compliers.
CCDM Clinical Trial Design 3
What is the role of a Data Safety Monitoring Board (DSMB) in clinical trial design?