Maraviroc, risks and benefits: a review of the clinical literature

Maraviroc represents the first licensed CCR5 co-receptor antagonist from the new antiretroviral (ARV) drug-class of entry inhibitors.

Results of Phase III clinical trials in three-drug-class experienced patients have presented maraviroc as a promising new agent for treatment of HIV-1-infection. Maraviroc (b.i.d./q.d.) + optimised background therapy (OBT) provided significantly superior virological control and CD4+ increases compared with placebo + OBT at 48 weeks, with no clinically relevant differences in the safety profile between the maraviroc and the placebo groups.

Its proven efficacy in cases of virological failure and three-class ARV-drug resistance is a major benefit of maraviroc compared to the so far commercially available drugs from existing (non-) nucleoside reverse transcriptase inhibitors ([N]NRTI) and protease inhibitors drug-classes, particularly in times of increasing ARV drug resistance. Moreover, the tolerability profile of the drug makes maraviroc particularly appealing as a combination partner in ARV therapy. As maraviroc however is only effective against CCR5-tropic HIV-1, tropism testing is required before initiation of treatment. Tropism-testing possibilities are still limited, and presently only possible at high costs. The main constraints to be considered in the clinical use of maraviroc are the declining number of CCR5-tropic patients with advanced HIV-1 disease owing to tropism-shifting and the occurrence of drug-drug interactions, requiring regular dose adaptations. The true clinical value of this new substance and its future role in the treatment of HIV-1-infection remains to be defined by further data from clinical studies and by future experiences of practitioners.