Brand versus generic: addressing non-adherence, secular trends and non-overlap

Area of Science:

• Pharmacoeconomics
• Pharmacoepidemiology
• Biostatistics

Background:

• Generic drugs provide cost-effective alternatives to brand-name medications.
• Assessing therapeutic equivalence post-market is crucial for regulatory bodies.
• Immediate-release venlafaxine (IR venlafaxine) serves as a case study for developing such methods.

Purpose of the Study:

• To develop and apply a novel methodology for assessing therapeutic equivalence of generic versus brand-name drugs in a real-world setting.
• To evaluate the therapeutic equivalence of generic IR venlafaxine compared to its brand-name counterpart.
• To address methodological challenges including patient non-adherence, time trends, and limited treatment overlap.

Main Methods:

• Utilized a large insurance claims dataset from OptumLabs^®.
• Extended regression discontinuity methods to survival curves to estimate causal effects for time-to-event outcomes.
• Employed G-computation to handle confounding and time-varying factors.

Main Results:

• The developed methodology successfully addressed challenges like non-adherence and secular trends.
• No statistically significant evidence was found to suggest a lack of therapeutic equivalence between generic and brand-name IR venlafaxine.
• The study demonstrates the feasibility of using large claims data for post-market therapeutic equivalence assessments.

Conclusions:

• The findings support the therapeutic equivalence of generic and brand-name IR venlafaxine.
• The proposed methodology offers a robust framework for regulatory assessment of drug equivalence.
• Real-world data analysis is a valuable tool for post-market drug evaluation and pharmacovigilance.