Study DesignGlossary Term
A clinical trial in which both the participants and the investigators know which treatment is being administered, without any blinding or masking procedures.
An open-label study dispenses with the concealment of treatment assignments that characterizes blinded trials, allowing all parties to know which intervention each participant receives. This transparency can be either a deliberate design choice or a practical necessity. Some studies are designed as open-label from the outset, while others may include open-label phases following completion of a blinded treatment period, allowing participants who received placebo to access active treatment.
Open-label designs are employed in various contexts where blinding is impractical, unnecessary, or unethical. Studies of surgical interventions, medical devices, or treatments with distinctive side effects may be impossible to blind convincingly. Early-phase studies exploring safety and tolerability may use open-label designs when precise efficacy assessment is not the primary objective. Long-term extension studies often operate as open-label to provide continued access to promising treatments while gathering additional safety data. Studies comparing treatments that require fundamentally different administration procedures may necessitate open-label conduct.
The absence of blinding in open-label studies introduces potential for bias that must be acknowledged and addressed. Participants who know they are receiving active treatment may report more favorable outcomes due to expectations, while those aware of receiving placebo may report worse outcomes or discontinue prematurely. Investigators may unconsciously assess or record outcomes differently based on treatment knowledge. These biases are particularly concerning for subjective endpoints. Open-label studies should therefore employ objective outcome measures when possible, use blinded endpoint adjudication committees, and interpret results with appropriate caution regarding the potential influence of unblinded assessment.
Long-term extension
"Following completion of the 12-week blinded treatment period, all participants were offered enrollment in an open-label extension study to receive the investigational drug for up to two additional years."
Surgical trial
"The trial comparing surgical intervention to medical management was conducted as an open-label study because the nature of the treatments made blinding impossible, though outcome assessors were blinded to treatment assignment."
The fraction of an administered dose of a drug that reaches the systemic circulation unchanged, and the rate at which this occurs.
A group of participants in a clinical trial who receive a comparator treatment, placebo, or no treatment to serve as a baseline for evaluating the effects of the investigational intervention.
A clinical trial design in which participants receive multiple treatments in sequence, with each participant serving as their own control by receiving all study treatments during different periods.
A systematic approach to increasing the dose of an investigational product during a clinical trial, typically employed in early-phase studies to identify safe and potentially effective dose levels.
A clinical trial in which both the participants and the investigators are unaware of the treatment assignments, providing maximal protection against bias in the conduct and assessment of the study.
A clinical trial in which both the participants and the investigators know which treatment is being administered, without any blinding or masking procedures.
An open-label study dispenses with the concealment of treatment assignments that characterizes blinded trials, allowing all parties to know which intervention each participant receives. This transparency can be either a deliberate design choice or a practical necessity. Some studies are designed as open-label from the outset, while others may include open-label phases following completion of a blinded treatment period, allowing participants who received placebo to access active treatment.
Open-label designs are employed in various contexts where blinding is impractical, unnecessary, or unethical. Studies of surgical interventions, medical devices, or treatments with distinctive side effects may be impossible to blind convincingly. Early-phase studies exploring safety and tolerability may use open-label designs when precise efficacy assessment is not the primary objective. Long-term extension studies often operate as open-label to provide continued access to promising treatments while gathering additional safety data. Studies comparing treatments that require fundamentally different administration procedures may necessitate open-label conduct.
The absence of blinding in open-label studies introduces potential for bias that must be acknowledged and addressed. Participants who know they are receiving active treatment may report more favorable outcomes due to expectations, while those aware of receiving placebo may report worse outcomes or discontinue prematurely. Investigators may unconsciously assess or record outcomes differently based on treatment knowledge. These biases are particularly concerning for subjective endpoints. Open-label studies should therefore employ objective outcome measures when possible, use blinded endpoint adjudication committees, and interpret results with appropriate caution regarding the potential influence of unblinded assessment.
Long-term extension
"Following completion of the 12-week blinded treatment period, all participants were offered enrollment in an open-label extension study to receive the investigational drug for up to two additional years."
Surgical trial
"The trial comparing surgical intervention to medical management was conducted as an open-label study because the nature of the treatments made blinding impossible, though outcome assessors were blinded to treatment assignment."
The fraction of an administered dose of a drug that reaches the systemic circulation unchanged, and the rate at which this occurs.
A group of participants in a clinical trial who receive a comparator treatment, placebo, or no treatment to serve as a baseline for evaluating the effects of the investigational intervention.
A clinical trial design in which participants receive multiple treatments in sequence, with each participant serving as their own control by receiving all study treatments during different periods.
A systematic approach to increasing the dose of an investigational product during a clinical trial, typically employed in early-phase studies to identify safe and potentially effective dose levels.
A clinical trial in which both the participants and the investigators are unaware of the treatment assignments, providing maximal protection against bias in the conduct and assessment of the study.