Double-Blind Study
A clinical trial where neither participants nor researchers know who receives active treatment versus placebo. Double-blinding prevents bias in outcome assessment and symptom reporting. It is the standard design for pivotal Phase III peptide drug trials.
Technical Context
Maintaining blinding for injectable peptide drugs requires careful matching: the active drug and placebo must be in identical devices (same pen type, cartridge appearance, injection volume, needle gauge), the solutions must have the same appearance (colour, viscosity), and injection-related sensations should be similar (injection site reactions could theoretically unblind, which is why ISR rates are carefully compared between groups). In-trial blinding can be compromised by distinct pharmacological effects — nausea with GLP-1 RAs may indicate active treatment to perceptive participants or investigators. To mitigate this, trials may use matching placebos with added components to produce similar mild effects (rarely done), or rely on centralised outcome assessment by blinded adjudication committees to remove investigator bias.