The use of two potent, well-tolerated, drugs could permit the maintenance of virologic suppression even in heavily pretreated people living with HIV. In this retrospective, multicenter, simplification study (NCT03348449), we included those patients with virologic suppression who switched to raltegravir (RAL) plus boosted darunavir (b/DRV). Overall, 345 patients (75 females, 25%) were included. Patients were largely pretreated (mean, 9.4 regimens), suppressed for a median of 41.1 months. Fifty patients had ≥1 mutation against DRV. At 96 weeks, the efficacy by intention-to-treat analysis (snapshot) was 73% (95%CI, 68.4–77.8%), but 97.1% (95%CI, 95.4–98.9) excluding changes due to non-virologic reasons, and virologic failure was rare (0.9%; 95%CI, 0.1–1.2%). Median CD4/CD8 ratio increased from 0.59 to 0.62 (p < 0.01), CD4+ cell count by +90 cells/µl (p < 0.01), and mean estimated glomerular filtration rate (eGFR) increased from 85.2 to 88.5 ml/min at 96 weeks, greater for patients receiving tenofovir disoproxil fumarate (eGFR, +3.6 ml/min, p = 0.04; serum phosphate +0.33 mg/dl; p < 0.01). There was a continued and significant improvement in the total cholesterol/high-density lipoprotein-cholesterol ratio. In conclusion, the simplification to a dual regimen with the combination of RAL and b/DRV is associated with maintenance of virologic suppression, even in largely pretreated patients, with improvements in CD4+ cell count, CD4/CD8 ratio, and in renal and lipid parameters.