Human immunodeficiency virus type 1 (HIV-1) RNA end points in HIV clinical trials: issues in interim monitoring and early stopping

Due to the desire to both shorten the length and reduce the size of clinical trials in human immunodeficiency virus (HIV) disease, the use of surrogate end points such as HIV-1 RNA is becoming increasingly standard. While these end points may be reasonable surrogates for the clinical effectiveness of drugs, a key point in their use as trial end points is the definition of a relevant duration of antiviral response. This definition is often complicated by the desire to perform interim reviews of ongoing laboratory end point trials. Unlike clinical end point trials, in which early clinical response is generally indicative of longer-term follow-up, it is yet to be determined whether short-term viral response adequately predicts the long-term durability of that response.