Swatch study: should we be cycling drugs?

An interesting study presented at the 41st ICAAC looked at cycling drugs rather than keeping patients on one continuous regimen. This harks back to the early days of antiretroviral therapy when cycling nucleoside analogues was evaluated.

In the Swatch study, patients were enrolled into one of three arms: stavudine (Zerit, d4T) + didanosine (ddI, Videx) and efavirenz (Sustiva/Stocrin), zidovudine (ZDV, Retrovir, AZT) + lamivudine (Epivir, 3TC) + nelfinavir (Viracept), or cycling between the two every three months. The study enrolled 161 patients and the dropout rate was 21, 22 and 16, respectively.

Using an intent to treat analysis, 69% of the cycled patients and 57% of the continuous therapy patients achieved a viral load < 400 copies/mL at 48 weeks. Under an on treatment analysis, 100% of the cycled patients and 85% of the continuous therapy patients achieved a viral load < 400 copies/mL at 48 weeks. The CD4+ T cell counts rise was similar, about 125 cells/mm3.

The resistance that did develop was mostly NNRTI-related in the efavirenz arm and lamivudine related in the nelfinavir arm, but some PI mutations were present in the nelfinavir arm as well.

Lipodystrophy occurred in all three arms and there were no significant differences. Adherence was excellent and similar in the three arms. The quality of life of patients appeared highest in the efavirenz arm and lowest in the nelfinavir arm.

C Boucher and others. SWATCH Study: a Multicenter Trial of Proactive Treatment Switching. Results at 48 weeks of Follow-Up. Oral Presentation I-672.