Background: Test-and-Treat models in newly diagnosed, HIV-1-infected patients have led to improved virologic outcomes, retention in care, and decreased mortality. Antiretroviral regimens used in this setting should optimally be a single-tablet regimen (STR), abacavir-sparing, well tolerated, and have a clinically-proven high genetic barrier to resistance. D/C/F/TAF (approved in Europe; under regulatory review in the US) is the only STR that possesses these qualities.
Methods: DIAMOND ( NCT03227861) is an ongoing, phase 3, single-arm, open-label, prospective, multicenter study assessing the efficacy/safety of D/C/F/TAF 800/150/200/10 mg in a Test-and-Treat model over 48 weeks. Adults diagnosed with HIV-1 infection within 14 days were immediately enrolled and started on D/C/F/TAF without screening/baseline laboratory information. Investigators reviewed screening/baseline laboratory findings as results became available; patients not meeting predefined safety or resistance stopping rules continued treatment. A planned interim analysis for retention and clinical outcomes was conducted when all patients reached Week 4 of enrollment.
Results: Baseline patient (N=109) characteristics were: median (range) age 28 (19-66) years; 13% women; 32% African American; median (range) HIV-1 RNA 4.6 (1.3-8.2) log10 copies/mL; 24% ≥100,000 copies/mL; median (range) CD4+ count 369 (7-1,082) cells/mm3; 21% < 200 cells/mm3. Median (range) time from diagnosis to screening/baseline was 5 (0-14) days; 29% of patients enrolled within 48 hours of diagnosis. At the interim analysis, 95.4% (104/109) of patients continued on D/C/F/TAF and only 5/109 discontinued (3 due to safety stopping rules, 1 protocol violation, 1 adverse event [AE]). Through Week 12, mean HIV-1 RNA decreased by 2.72 log10 copies/mL (n=41; Figure). Incidences of grade 3 (5.5%) and serious (2.8%) AEs were low, with no grade 4 AEs or deaths. Week 24 results will be available for presentation.
Conclusions: In the first known phase 3 trial of an STR in a Test-and-Treat model, a decline in HIV-1 RNA ≥2.00 log10 by Week 4 and patient retention of >95% on D/C/F/TAF were achieved at interim analysis, with no discontinuations due to predefined resistance stopping rules or lack of efficacy. Organizations utilizing Test-and-Treat models should consider D/C/F/TAF as a preferred treatment option as it is the only agent with phase 3 data supporting its use in this setting.


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