Favorable therapeutic response with an antiretroviral salvage regimen in an HIV-1-positive subject infected with a CRF11-cpx virus.

HIV drug resistance still represents a crucial problem in antiretroviral therapy. We report a case of a naive patient, harboring a CRF11-cpx virus, which showed drug resistance mutations in the reverse transcriptase. A drug resistance genotyping test was performed for the pol (protease, reverse transcriptase, and integrase) and V3 regions. The initial clinical parameter results showed a 4 log level of HIV-RNA (12,090 cp/ml) and a very low CD4(+) cell count (35 cells/μl). We designed an initial highly active antiretroviral therapy (HAART) regimen including lamivudine (3TC)+abacavir (ABC)+booster ritonavir (DRV/r). The virus was highly resistant to all nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) except for ABC, tenofovir (TDF), and efavirenz (EFV) and was susceptible to all protease inhibitors (PIs) and integrase inhibitors (INIs). A salvage regimen including raltegravir (RAL)+DRV/r was started. Ten months later, the immunovirological status shows CD4(+) 142/μl and HIV-RNA <37 cp/ml. Our results demonstrate the effectiveness of a treatment combination that includes RAL+DRV/r in a patient infected with a complex X4-tropic CRF11-cpx virus.