Clinical trials are crucial for advancing medical research and improving treatment options, but the terminology can be daunting. Here’s a comprehensive glossary of key terms to help you better understand clinical trials:
Phases of Clinical Trials:
- Phase 1: Focuses on safety. A small group of participants tests the treatment for safe dosage levels and side effects.
- Phase 2: Assesses efficacy and further evaluates safety in a larger group.
- Phase 3: Confirms effectiveness in a much larger population, often comparing the new treatment to the current standard of care.
- Phase 4: Post-approval studies monitor the treatment’s long-term effectiveness and safety.
Key Clinical Trial Outcomes:
- Progression-Free Survival (PFS): The length of time a patient lives without disease worsening.
- Overall Survival (OS): The time from the start of treatment until death from any cause.
- Disease-Free Survival (DFS): The period a patient remains free of disease after treatment.
- Objective Response Rate (ORR): The percentage of patients whose cancer partially or completely shrinks after treatment.
- Durable Response: The length of time a treatment continues to be effective after an initial response
Types of Trials and Study Designs:
- Randomized Controlled Trial (RCT): Participants are randomly assigned to experimental or control groups to reduce bias.
- Placebo-Controlled Trial: Some participants receive a placebo to compare its effect against the treatment.
- Double-Blind Study: Neither participants nor researchers know who is receiving the experimental treatment to prevent bias.
- Open-Label Study: Both participants and researchers know which treatment is being administered.
Other Key Terms:
- Adverse Event (AE): Unintended medical issues experienced during a trial, graded from mild to severe.
- Endpoints: Measurable outcomes used to evaluate treatment success (e.g., PFS, OS, quality of life).
- Biomarker: A biological indicator (e.g., a gene or protein) used to measure disease or predict treatment response.
- Protocol: A detailed plan outlining the trial’s objectives, design, and methods.
- Crossover Study: Participants switch between treatment groups during the trial.
- Eligibility Criteria: Specific conditions participants must meet to join a trial, such as age, disease stage, or prior treatments.
- Enrollment: The process of recruiting and registering participants for a trial.
- Hazard Ratio: A measure of how often a particular event happens in one group compared to how often it happens in another group, over time. In cancer research, hazard ratios are often used in clinical trials to measure survival at any point in time in a group of patients who have been given a specific treatment compared to a control group given another treatment or a placebo. A hazard ratio of one means that there is no difference in survival between the two groups. A hazard ratio of greater than one or less than one means that survival was better in one of the groups.
- Inclusion/Exclusion Criteria: Guidelines determining who can or cannot participate in a trial.
- Trial Arm: A group of participants receiving a specific intervention or placebo.
- Surrogate Endpoint: A substitute measure (e.g., biomarker response) used when direct measures like OS would take too long to observe.
- Statistical Significance: A measure indicating that trial results are unlikely to have occurred by chance.
- Toxicity: Side effects caused by the treatment, often monitored closely in trials.
By familiarizing yourself with these terms, you can engage more effectively in conversations about clinical trials and advocate for informed decisions. This knowledge empowers patients, caregivers, and advocates to navigate the clinical trial process with confidence.