Safety and Effectiveness of Highly Active Antiretroviral Therapy in Treatment-Naïve HIV Patients: Preliminary Findings of a Cohort Event Monitoring Study in Belarus

Antiretroviral drugs have well-documented evidence-based favorable benefit–risk ratios. Although various studies have investigated and characterized the safety profile of antiretroviral medicines, there are a limited number of studies evaluating the safety of first-line antiretroviral therapy (ART) in patients with a specific co-morbidity. A cohort event monitoring (CEM) study of the safety and effectiveness of antiretroviral medicines in a target population that has a significant level of co-morbidities (chronic infectious diseases, peripheral blood cytopenias) was implemented. The aim was to evaluate the safety profile of the highly active ART (HAART) in the target population and subpopulations with risk factors, to optimize the monitoring and decision-making procedure for subgroups of patients with specific types of co-morbidity, and to implement a more vigilant approach to therapy management in risk groups of patients.

Prospective observational CEM was implemented among HAART-naïve HIV-positive patients at four clinical sites from December 2012. Eligible patients were those starting first-line HAART. Close medical supervision of all enrolled patients, with regular clinical and laboratory monitoring, was provided by healthcare professionals within 1 year after commencement of therapy. Standardized forms were used for data collection on initial and subsequent visits. All objective or subjective deviations in condition (events) were assessed for a causal relationship with ART, and for severity, seriousness, reversibility, preventability, and pre-existing risk factors in the case of adverse drug reactions (ADRs).

A total of 518 HAART-naïve HIV-positive patients were enrolled in the CEM study. Of these patients, 65 % (337) experienced one or several ADRs related to one or more components of HAART. Most of the ADRs reported were non-serious, expected, common (very common), transient (correctable), or reversible. The most common were hematotoxic, hepatotoxic, and neurotoxic adverse reactions. In several cases, some types of toxicities, associated with zidovudine, efavirenz, and nevirapine, had a high level of severity, necessitating hospitalization and drug regimen or single-agent substitution. Severe cases of hematological, hepatobiliary, and psychiatric toxicities were associated with pre-existing risk factors.

CEM is an effective tool for safety and effectiveness monitoring and could be successfully implemented for intensive study of important safety issues and for overcoming knowledge gaps regarding safety. In order to achieve a favorable benefit–risk ratio for HAART in the specific sections of the population with pre-existing risk factors for development of ART toxicities, more vigilant consideration and careful assessment before therapy is commenced and further regular monitoring of key laboratory parameters is required.