Eighth International Congress on Drug Therapy in HIV Infection Glasgow, UK - 12-16 November 2006

Int Cong Drug Therapy HIV 2006 Nov 12-16;8:Abstract No. PL3.3

Luis Soto-Ramirez
Instituto Nacional de Ciencias Medicas y Nutricion, Mexico City, Mexico

PURPOSE OF THE STUDY: The availability of HAART that suppresses replication of HIV-1, has dramatically improved the prognosis of HIV-infected patients. Unfortunately, HAART does not durably suppress HIV replication in 20 to more than 50% of treatment-naïve patients and in up to 50-70% of treatment-experienced patients. In the majority of patients with viral rebound, drug-resistance is detected thorough genotypic and phenotypic assays, however both assays are still limited in their power to fully map antiviral resistance. Clinical interpretation of both assays is difficult and is not fully standardized, with the need of an expert most of the time. Resistance assays have showed us several differences in the development of resistance associated mutations according to the time of detection of clinical failure. Thymidine analog mutations (TAMs) have important impact on sequencing nucleoside analogs. When virological failure to a first ARV treatment is detected late as it happens in developing countries with les than ideal monitoring, 3 or more TAMs have been detected in up to 32% of cases, limiting importantly the number of drugs available for the salvage treatment.

Resistance assays have been also useful to detect primary drug resistance(PDR). New infections through transmission of drug-resistant strains to individuals who have never been exposed to therapy are now being increasingly reported and unfortunately correlate with suboptimal therapy response, which raises major public health concerns. PDR in most developed countries has shown different tendencies, for some as the US, a continuous increase with predominance of NNRTI resistance and for some others a declining prevalence. In the last case, it has been argued that transmission comes mainly from recently infected individuals. The scenario is probably different in developing countries where PDR is correlated to late assess of ART failure and an increase of unprotected sex in treated individuals. With the continuous increase in ART in developing countries, surveillance of PDR will become very important, however specific definitions for transmitted resistance are badly needed.

A better understanding of all the factors that are related to primary and secondary resistance are needed specially in developing countries, in order to make better use of the limited economical resources.

Plenary Session: New Challenges in Providing ART [IAS Session]

2006-11-12
PL3.3

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