Injection drug users (IDUs) require therapeutic regimens that are well tolerated, minimize drug interactions, and are easily administered to maximize adherence. Raltegravir has few side effects and can be combined with other therapeutic agents, including novel treatments for hepatitis C virus (HCV). However, prior research has shown that once-daily raltegravir administration may be inferior to twice daily dosing. This limits its use in IDUs, especially those in directly observed treatment (DOT) algorithms.
Kris Stewart, MD, of the University of Saskatchewan, Saskatoon, Canada, and colleagues, evaluated HIV-infected IDUs attending inner city clinics in Vancouver, Canada, treated with once daily raltegravir- containing regimens, often within a DOT program.
Of 150 patients (88% male), DOT was the mode of administration in 85% of cases. Median CD4 cell count and HIV plasma viral load (pvl) at baseline were 350 cells/mm3 and 28,500 copies/mL. According to the researchers, over a median follow-up period of 12 (6-18) months, 80% of patients had maximal virologic suppression. Their CD4 cell counts increased by a median 150 cells/mm3. Median adherence therapy exceeded 90%. Virologic breakthrough (pvl >400 copies/mL) occurred in 10% of cases. But re-suppression was achieved in all cases over the subsequent three months. There were no cases of emergent raltegravir resistance. Further, there were no cases of treatment-emergent raltegravir toxicity leading to drug discontinuation. Raltegravir was well tolerated in an IDU population, with a high degree of adherence, the researchers concluded.
“Once-daily administration was highly effective, with minimal virologic breakthrough and no drug resistance,” they noted. Once-daily raltegravir “can be an important component of HAART in this (and other) populations when a safe and effective medication is required and twice daily dosing is not feasible.”