Phase I dose-escalation studies MCQs With Answer
Phase I dose-escalation studies are the first-in-human clinical trials that determine initial safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of a new drug. This quiz set is designed for M.Pharm students to deepen understanding of study designs (e.g., 3+3, model-based), selection of starting dose from preclinical data, definitions and handling of dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), sentinel dosing, cohort escalation rules, and regulatory expectations (ICH M3(R2), FDA). Questions emphasize practical decision-making, adaptive strategies, and interpretation of PK/PD data commonly encountered in Phase I dose-escalation programs.
Q1. What is the primary objective of a Phase I dose-escalation study?
- To compare efficacy of two marketed drugs
- To evaluate long-term safety over several years
- To determine safety, tolerability and recommend a safe dose for further studies
- To assess cost-effectiveness of a new formulation
Correct Answer: To determine safety, tolerability and recommend a safe dose for further studies
Q2. Which preclinical parameter is most commonly used to select the recommended starting dose for first-in-human studies?
- Maximum tolerated dose (MTD) in healthy volunteers
- No-observed-adverse-effect level (NOAEL) from animal studies converted to human equivalent dose
- ED50 (effective dose in 50% of animals)
- Cmax achieved in rodents after oral dosing
Correct Answer: No-observed-adverse-effect level (NOAEL) from animal studies converted to human equivalent dose
Q3. In a classical 3+3 dose-escalation design, what action is taken if 2 of 3 patients in a cohort experience a dose-limiting toxicity (DLT)?
- Escalate dose for the next cohort
- Expand cohort to 6 patients at the same dose
- De-escalate to a lower dose and expand to 6 patients
- Terminate the trial immediately
Correct Answer: De-escalate to a lower dose and expand to 6 patients
Q4. Dose-limiting toxicity (DLT) is best described as which of the following?
- An adverse event unrelated to study drug
- A predefined toxicity that prevents further dose escalation during the assessment period
- A mild laboratory abnormality that resolves within 24 hours
- Any adverse event occurring after study completion
Correct Answer: A predefined toxicity that prevents further dose escalation during the assessment period
Q5. Which design is a model-based alternative to the 3+3 method that estimates the MTD using statistical modeling?
- Parallel-group randomized design
- Continual reassessment method (CRM)
- Case-control design
- Cross-over design
Correct Answer: Continual reassessment method (CRM)
Q6. What is the main advantage of model-based dose-escalation designs over rule-based designs?
- They always require fewer patients than any rule-based design
- They use accumulated data to target a dose with a specific toxicity probability more efficiently
- They eliminate the need for safety monitoring committees
- They do not require preclinical data
Correct Answer: They use accumulated data to target a dose with a specific toxicity probability more efficiently
Q7. Sentinel dosing in Phase I studies refers to which practice?
- Dosing a single subject at the maximum planned dose first
- Dosing two or more subjects sequentially with safety observation before dosing remaining cohort members
- Administering placebo to sentinel subjects throughout the study
- Only dosing subjects with sentinel lymph node biopsies
Correct Answer: Dosing two or more subjects sequentially with safety observation before dosing remaining cohort members
Q8. Which regulatory guideline specifically addresses first-in-human clinical trials and nonclinical information required?
- ICH E6 (Good Clinical Practice)
- ICH M3(R2) — Nonclinical safety studies for the conduct of human clinical trials
- ICH Q9 — Quality Risk Management
- ICH E2A — Clinical Safety Data Management
Correct Answer: ICH M3(R2) — Nonclinical safety studies for the conduct of human clinical trials
Q9. What is the purpose of an expansion cohort added after dose-escalation in a Phase I trial?
- To test a completely unrelated compound
- To further characterize safety, PK/PD, and preliminary efficacy at the recommended phase II dose
- To shorten the duration of patient follow-up
- To replace a control arm in later-phase trials
Correct Answer: To further characterize safety, PK/PD, and preliminary efficacy at the recommended phase II dose
Q10. For oral drugs, which design element is commonly included in Phase I to assess drug-food interactions?
- Repeated intravenous administration without food
- Single-dose fed and fasted crossover cohort to compare PK
- Exclusion of all subjects who eat during the study
- Only measuring pharmacodynamics, not PK
Correct Answer: Single-dose fed and fasted crossover cohort to compare PK
Q11. In multiple ascending dose (MAD) cohorts, which parameter indicates drug accumulation on repeated dosing?
- Clearance measured after single dose only
- Accumulation ratio (Rac) calculated from steady-state AUC or Cmax
- Time to first adverse event
- Absolute bioavailability
Correct Answer: Accumulation ratio (Rac) calculated from steady-state AUC or Cmax
Q12. Modified Fibonacci sequence is used in dose-escalation to:
- Determine statistical significance of PK parameters
- Provide conservative stepwise dose increases early in escalation
- Randomize subjects to treatment arms
- Calculate sample size for Phase III trials
Correct Answer: Provide conservative stepwise dose increases early in escalation
Q13. Which factor is least important when defining the DLT assessment window in oncology Phase I trials?
- Time course of expected drug-induced toxicities
- Pharmacokinetic half-life of the drug
- Operational convenience of clinic visits
- Onset timing of immune-mediated adverse events
Correct Answer: Operational convenience of clinic visits
Q14. In biologics and immuno-oncology agents, what special consideration often affects Phase I dose-escalation?
- Short half-life eliminates need for PK sampling
- Immune-related adverse events and atypical dose-toxicity relationships may require modified escalation and longer DLT windows
- They always follow the 3+3 design without exceptions
- No preclinical safety studies are necessary
Correct Answer: Immune-related adverse events and atypical dose-toxicity relationships may require modified escalation and longer DLT windows
Q15. Intra-patient dose escalation means:
- Each patient is randomized to different fixed doses
- Individual patients can receive increasing doses during the course of treatment if tolerated
- Doses are escalated only between cohorts, never within a patient
- All patients get dose reductions regardless of toxicity
Correct Answer: Individual patients can receive increasing doses during the course of treatment if tolerated
Q16. Which PK parameter is most informative about the time required to reach steady state during repeated dosing?
- Cmax after single dose
- Drug half-life (t1/2)
- Bioavailability (F)
- Volume of distribution (Vd) only
Correct Answer: Drug half-life (t1/2)
Q17. What is a key stopping rule in many Phase I escalation protocols?
- Stopping if any grade 1 adverse event occurs
- Stopping escalation if a predefined number of DLTs is observed at a dose level
- Stopping only at trial completion date regardless of safety
- Stopping when PK shows linearity
Correct Answer: Stopping escalation if a predefined number of DLTs is observed at a dose level
Q18. Which statement about maximum tolerated dose (MTD) is correct?
- MTD is the dose that produces no adverse events
- MTD is the highest dose with an acceptable rate of DLTs predefined in the protocol
- MTD is determined solely by pharmacokinetic modeling
- MTD is always chosen as the starting dose for Phase II without further evaluation
Correct Answer: MTD is the highest dose with an acceptable rate of DLTs predefined in the protocol
Q19. Which of the following best describes the role of pharmacodynamic (PD) biomarkers in Phase I dose-escalation?
- PD biomarkers are only used to assess toxicity unrelated to mechanism
- PD biomarkers can help demonstrate target engagement and inform dose selection beyond safety alone
- PD biomarkers replace the need for PK sampling
- PD biomarkers are irrelevant until Phase III
Correct Answer: PD biomarkers can help demonstrate target engagement and inform dose selection beyond safety alone
Q20. For combinations of two investigational agents in a Phase I escalation, which approach is commonly used?
- Treat combination like a single agent and ignore interactions
- Use a combination escalation design (e.g., factorial or modified 3+3) to assess safety and find the recommended combination dose
- Administer each agent at their established Phase III doses without adjustments
- Delay any pharmacokinetic sampling because interactions are unlikely
Correct Answer: Use a combination escalation design (e.g., factorial or modified 3+3) to assess safety and find the recommended combination dose
