Source: DGNews  |  Posted 3 years ago

By Ed Susman

MEXICO CITY -- August 7, 2008 -- Patients who were experiencing injection-site reactions with the use of enfuvirtide were able to switch treatment to the new integrase inhibitor raltegravir without experiencing a rebound of human immunodeficiency virus (HIV), according to research presented here at the 17th International AIDS Conference (AIDS 2008).

Patients who take enfuvirtide frequently experience injection-site reactions that make tolerance and compliance with the regimen problematic, explained Annie Talbot, MD, University of Montreal, Montreal, Quebec, and a fellow at Stanford University, Stanford, California, discussing her poster presentation here on August 5.

"In the TORO [T-20 Versus Optimized Background Regimen Only] studies, 98% of patients had at least 1 injection-site reaction over the course of 48 weeks," said Dr. Talbot. "About 4% of patients at 48 weeks discontinued treatment with enfuvirtide as a result of injection-site reactions."

Dr. Talbot attempted to study the safety and efficacy of an off-label approach to therapy with raltegravir -- switching patients who were well controlled on their enfuvirtide regimen to raltegravir. Twenty-five highly treatment-experienced patients were followed for 12 weeks.

"We found that, with the switch to the oral raltegravir, the injection-site reactions resolved in all patients," said Dr. Talbot. "All hepatic and haematological parameters also remained stable at week 12 after the switch."

All study subjects continued to suppress the virus after the switch was made. One person showed a detectable viral load of 63 copies/mL (above the level of detection using the 50-copy assay).

"You have to be careful in making these switches, because we did observe that in 11 of our 25 patients there was a fall of as much as a 150 cell/mm³ drop," Dr. Talbot cautioned.

On the other hand, she noted that some patients gained as much as 150 cells after the switch to raltegravir. Overall, the mean CD4 cell count for the whole group was 386 at baseline and 292 at the end of the 12-week observation period (P = .724), a nonsignificant difference.

"Longer follow-up is required to ensure the durability of the observed benefits and to supervise the evolution of the CD4-positive cell count," Dr. Talbot concluded.

[Presentation title: 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. Abstract TUPE0112]