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Retrospective analysis of a switch from enfuvirtide to raltegravir in patients with undetectable viral load: efficacy and safety at 12 weeks in a Montreal Cohort
A. Talbot1, N. Machouf2, R. Thomas2, S. Marcotte1, R. Therrien1, S. Dufresne3, R. Lalonde4
1University of Montreal, UHRESS, Montreal, Canada, 2Actuel, Medecine, Montreal, Canada, 3Quartier Latin, Medecine, Montreal, Canada, 4MgGill University, UHRESS, Montreal, Canada
Background: Enfuvirtide is a potent ARV given subcutaneously in treatment-experienced patients. However, its use is associated with injection site reactions motivating patients and providers to seek an effective substitute. When raltegravir became available in Québec, some virologically suppressed patients where switched from enfuvirtide to raltegravir. We sought to evaluate the efficacy and safety of this strategy in patients with viral loads less than 50 copies/ml.
Methods: Patients were included in this multi-center retrospective analysis if their HIV-viremia (VL) was <50copies/mL and the only change in therapy was a switch from enfuvirtide to raltegravir. Data including demographics, history of HIV-infection, ARV, and laboratory data were abstracted from medical records. Changes in CD4, VL and safety parameters at 12 weeks were analysed by Wilcoxon-test.
Results: Eighteen highly treatment-experienced patients had been included: median time on ARV was 11.5 years (IQR:8.8-12.5). 94% were male, median age was 43 and median duration of HIV-infection was 16 years (IQR:12.8-18.3). All patients had resistance mutations to NRTIs, NNRTIs and PIs. The median duration of enfuvirtide use was 21 months (IQR:12-44). All patients were on boosted-PIs in conjunction with enfuvirtide (boosted-darunavir in 9/18 patients, boosted-tipranavir in 7/18, other boosted-PI in 2/18), in addition 4 patients were also on NNRTI (3/18 on etravirine, 1/18 on efavirenz). 12-week data were available for 11/18 patients. All of them remained undetectable (VL<50copies) and no changes were observed in the CD4 counts (p=0.135). All hepatic and haematological parameter also remain stable at 12 week after the switch.
Conclusions: A switch from enfuvirtide to raltegravir in fully suppressed did not lead to virologic breakthrough without improvements in the CD4 cell-count at 12 weeks. Safety parameters seems promising with resolving injection sites reactions.. Longer follow up is required to ensure the durability of the observed benefits.
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