HIV-1 Protease Inhibitors Resistance Profiles in Patients with Virological Failure on LPV/r-based 2nd Line Regimen in Cambodia

Objective: To describe the ARV resistance profiles of patients experiencing virological failure after at least 6 months on LPV /r -based 2 nd line regimen in Cambodia.Design: Retrospective analysis of resistance testing of 89 patients with detectable viral load under LPV /r -based 2 nd line regimen.Methods: Bulk sequencing of HIV-1 protease, reverse transcriptase and integrase PCR products.Results: Protease gene amplification was successful for 71/89 patients (80%).All were infected by CRF01_AE viruses.Among them, 42 did not present any resistance to PIs.A high level of resistance to PIs was observed for the 29 remaining patients.Twenty-six were resistant to LPV /r (8 possibly resistant).Twenty-eight, 21 and 20 were also found resistant to IDV, ATV/ r and FPV/ r , respectively.Twenty-six were resistant to NFV (11 possibly) and 22 to SQV/ r (9 possibly).Finally, 22/29 (75.8%) were resistant to at least 3 PIs.Interestingly, 78.6% (22/29) were found sensitive to DRV/ r .In this group, a high frequency of resistance to RTIs including ETV was also reported.No resistance to raltegravir (RAL) or elvitegravir (EVG) was observed (n=24).Detailed ARV histories documented for 15 patients revealed past exposition to multiple RTIs and PIs.Conclusion: Almost 2/3 of patients (60/89) with virological failure on LPV /r -based 2 nd line in our study were not in urgent need for treatment change.In contrast, switching treatment was clearly required for 1/3 (29/89) presenting high level of resistance to PIs and RTIs.For those patients, DRV, RAL/EVG, and potentially ETV, could be good candidates for 3 rd line ARV regimen if available.