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Humanized NOD/SCID/IL2rγnull (hu-NSG) Mouse Model for HIV Replication and Latency Studies
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Risk of Developing Low-Level Viral Rebound Among People With HIV Receiving 2- or 3-Drug Regimens: A Case-Control
Alessandra Vergori1, Adriana Cervo2, Ashley Roen3
1Viral Immunodeficiency Unit, National Institute for Infectious Diseases Lazzaro Spallanzani, IRCCS, Rome, Italy.
Open Forum Infectious Diseases
|May 22, 2026
Summary
This study found no significant difference in low-level viral rebound (LLVR) risk between 2-drug and 3-drug regimens for people with HIV. The data suggests 2-drug regimens are a safe option for maintaining viral suppression.
Area of Science:
- Virology
- Immunology
- Pharmacology
Background:
- The comparative risk of low-level viral rebound (LLVR) in individuals with human immunodeficiency virus type 1 (HIV-1) on 2-drug regimens (2DR) versus 3-drug regimens (3DR) is not well-established.
- Achieving and maintaining HIV-1 RNA suppression is crucial for long-term patient outcomes.
Purpose of the Study:
- To compare the risk of LLVR in persons with HIV (PWH) initiating 2DR versus 3DR after achieving virological suppression.
- To evaluate the association between antiretroviral therapy regimen type and LLVR incidence.
Main Methods:
- A matched 1:3 case-control study within the ICONA cohort.
- Cases were defined as PWH experiencing single or consecutive HIV-RNA between 51-199 copies/mL post-virological suppression.
- Conditional logistic regression and Kaplan-Meier methods were used to analyze LLVR risk associated with 2DR versus 3DR.
Main Results:
- Among 1033 PWH, 2DR use was similar between cases (25%) and controls (29%).
- Cumulative LLVR incidence at 2 years post-suppression was 2.7% (single event) and 1.8% (consecutive events).
- Adjusted analyses showed no conclusive association between 2DR/3DR and LLVR risk (aOR, 0.86; 95% CI, .57-1.29).
Conclusions:
- The study provides evidence that 2-drug regimens do not significantly increase the risk of low-level viral rebound compared to 3-drug regimens.
- A higher risk of LLVR (>29%) with 2DR compared to 3DR can be excluded, supporting the use of 2DR for HIV-1 RNA suppression.
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