Mosaic effectiveness: measuring the impact of novel PrEP methods
David V Glidden1, Megha L Mehrotra1, David T Dunn2
1Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
The Lancet. HIV
|October 2, 2019
Summary
New long-acting pre-exposure prophylaxis (PrEP) should be evaluated for "mosaic effectiveness," measuring its benefit alongside daily oral PrEP, not just in isolation. This approach better reflects real-world use and public health impact for HIV prevention.
Area of Science:
- HIV Prevention Research
- Pharmacology
- Public Health
Background:
- Ongoing trials evaluate long-acting pre-exposure prophylaxis (PrEP) agents against daily oral tenofovir disoproxil fumarate and emtricitabine.
- Current trial designs often compare new PrEP methods in isolation, not reflecting real-world scenarios where both oral and long-acting options may be available.
- This limitation may underestimate the public health value of novel long-acting PrEP agents.
Purpose of the Study:
- To propose an alternative standard for evaluating long-acting PrEP agents.
- To introduce the concept of "mosaic effectiveness" to measure a new product's impact when used concurrently with oral PrEP.
- To advocate for regulatory standards that incorporate mosaic effectiveness for better HIV prevention progress.
Main Methods:
- Conceptual framework development for 'mosaic effectiveness'.
- Illustrative scenarios demonstrating the application of mosaic effectiveness.
- Comparison of mosaic effectiveness against traditional non-inferiority measures.
Main Results:
- A novel long-acting PrEP product might not achieve non-inferiority compared to oral PrEP alone.
- However, the same product can demonstrate substantial mosaic effectiveness, indicating significant public health benefit.
- This highlights the potential value of new agents even if not strictly superior to existing options in all contexts.
Conclusions:
- Mosaic effectiveness offers a more relevant measure of a new PrEP product's real-world impact.
- Regulatory agencies should consider mosaic effectiveness alongside comparative effectiveness for approving new HIV prevention tools.
- Adopting this metric can accelerate progress in combating the HIV epidemic by better valuing innovative PrEP strategies.
