The WHO guidelines also recommend that premature modification from first-line to second-line treatment should be avoided, with the assumption that the provision of second-line drugs is in the public sector and the availability is usually limited. This may mean that clinicians are not willing to modify the regimen immediately in the presence of treatment failure if virological failure cannot be confirmed. The higher rate of modification after virological failure in TAHOD

than after immunological and clinical failure lends support to this interpretation. However, there remain a large R428 proportion of patients (nearly 40%) who continue the same failing regimen 1 year after identification of virological failure, which

is probably a result of the limited treatment options available. We found that advanced disease stage (CDC category C), a lower CD4 cell count and a higher HIV viral load were associated with a higher rate of treatment modification after failure. This probably indicates that the clinicians in TAHOD clinics were prioritizing treatment options to those failed patients with more advanced immune deficiency as a result of limited resources. In a case note and questionnaire-based audit in the United Kingdom [14], after virological failure (defined as a viral load rebound from undetectable, not reaching an undetectable level, and/or an increase in viral load), change of therapy was found to occur in <4 months in 43% of patients, in 4–6 months in 20% of patients MK-1775 clinical trial and in >6 months in 34% of patients. Of the patients with virological failure who had their treatment modified, 48% switched to three or more new drugs, 32% to two new drugs and 20% to one new drug. In another study from the United Kingdom, Collaborative HIV Cohort (CHIC) [15], only one-third of patients remained on a failing regimen for more than 6 months after virological rebound of >400 copies/mL, Fenbendazole and the

proportions were 20% and 9% at 1 and 2 years after rebound, respectively. The rate of treatment modification after treatment failure in TAHOD patients is clearly slower than that seen in the United Kingdom, where routine HIV viral load tests and second-line treatment options are readily available. Treatment failure was only one of the reported reasons for modification of treatment after identification of failure. These clinical data provide an insight into clinical practice with regard to HIV treatment and care in the Asia and Pacific region. Adverse events were reported to be a major reason for treatment change after initiation, both in TAHOD [13,16] and in other cohorts [14]. This suggests that the TAHOD clinicians are aware of the adverse effects associated with cART and are ready to change treatment if toxicity is present.