Patients with Multidrug-resistant HIV Achieve Good Results after Switching from Enfuvirtide (Fuzeon) to Raltegravir (Isentress)

By Liz Highleyman

The first-ever entry inhibitor, enfuvirtide (T-20; Fuzeon) offered hope to many treatment-experienced HIV patients who had developed extensive drug resistance, at a time when few new agents were emerging from the development pipeline. But enfuvirtide is difficult to take, since it must be injected twice daily and often causes injection site reactions; it is also one of the most expensive AIDS drugs.

More options for "salvage" therapy for highly treatment-experienced patients became available in 2007, with the approval of the first CCR5 antagonist (a different type of entry inhibitor) and the first integrase inhibitor.

In the June 19, 2008 issue of AIDS, Canadian researchers reported outcomes in 35 adult HIV patients who chose to substitute the new integrase inhibitor, raltegravir (Isentress), for enfuvirtide. As background, the authors noted that raltegravir has the advantages of easier administration and improved tolerability.

The 35 patients described in the article replaced enfuvirtide with raltegravir while keeping the rest of their antiretroviral regimen (NRTIs, NNRTIs, and/or protease inhibitors) unchanged. All maintained virological suppression after a median of 7 months, except for 1 individual who experienced a transiently detectable viral load after 5 months.

In conclusion, the authors wrote, "The new regimen was well tolerated with no apparent new drug-related adverse clinical or laboratory events."

7/15/08

Reference
M Harris G Larsen, and JS Montaner. Outcomes of multidrug-resistant patients switched from enfuvirtide to raltegravir within a virologically suppressive regimen. AIDS 22(10): 1224-1226. June 19, 2008.