Forum for Collaborative HIV Research. Immune-based therapies: a review of clinical endpoints used in trials of selected immunologic agents

Immunological responses and long-term treatment interruption after human immunodeficiency virus type 1 (HIV-1) lipopeptide immunization of HIV-1-infected patients: the LIPTHERA study

We studied the time course of immunological and virological markers after highly active antiretroviral therapy (HAART) interruption in chronically human immunodeficiency virus type 1 (HIV-1)-infected patients immunized with an HIV lipopeptide preparation. In a prospective open pilot study, 24 HIV-1-infected HAART-treated patients with undetectable plasma viral loads (pVLs) and CD4(+) T-cell counts above 350/mm(3) were immunized at weeks 0, 3, and 6 with a candidate vaccine consisting of six HIV lipopeptides. At week 24, patients with pVLs of <1.7 log(10) copies/ml were invited to stop taking HAART. Antiretroviral therapy was resumed if the pVL rose above 4.47 log(10) copies/ml and/or if the CD4(+) cell count fell below 250/mm(3). Immunological and virologic parameters were studied before and after HAART interruption. The median baseline and nadir CD4(+) cell counts were 482 (interquartile range [IQR], 195 to 826) and 313 (IQR, 1 to 481)/mm(3), respectively. New specific CD8(+) cell responses to HIV-1 epitopes were detected after immunization in 13 (57%) of 23 assessable patients. Twenty-one patients were evaluated 96 weeks after HAART interruption. The median time to pVL rebound was 4 weeks (IQR, 2 to 6), and the median peak pVL was 4.26 (IQR, 3 to 5) log(10) copies/ml. Thirteen of these 21 patients resumed HAART a median of 60 weeks after immunization (IQR, 9.2 to 68.4 weeks), when the median pVL was 4.8 (IQR, 2.9 to 5.7) log(10) copies/ml and the median CD4(+) cell count was 551 (IQR, 156 to 778)/mm(3). Eight patients were still off therapy at 96 weeks, with a median pVL of 4 (IQR, 1.7 to 4.6) log(10) copies/ml and a median CD4(+) cell count of 412 (IQR, 299 to 832)/mm(3). No clinical disease progression had occurred. Despite the lack of a control arm, these findings warrant a randomized study of therapeutic vaccination with HIV lipopeptides followed by long-term HAART interruption in AIDS-free chronically infected patients.

Reporting and evaluation of HIV-related clinical endpoints in two multicenter international clinical trials

PURPOSE

The processes for reporting and review of progression of HIV disease clinical endpoints are described for two large phase III international clinical trials.

METHOD

SILCAAT and ESPRIT are multicenter randomized HIV trials evaluating the impact of interleukin-2 on disease progression and death in HIV-infected patients receiving antiretroviral therapy. We report definitions used for HIV progression of disease endpoints, procedures for site reporting of such events, processes for independent review of reported events by an Endpoint Review Committee (ERC), and the procedure for adjudication of differences of opinion between reviewers.

RESULTS

Of 473 events reported through May 1, 2006, 28% were judged by an ERC to meet "confirmed" criteria and 38% to meet "probable" criteria; 34% were classified "does not meet criteria." For diseases with >5 case reports, the proportion accepted as either "confirmed" or "probable" events was highest for cervical cancer (100%), non-Hodgkin's lymphoma (88%), cryptococcosis (82%), and cryptosporidiosis (80%) and was lowest for HIV encephalopathy (25%), HIV wasting syndrome (33%), and multidermatomal herpes zoster (35%). 25% of cases required adjudication between reviewers before diagnostic certainty was assigned.

CONCLUSION

Important requirements for HIV trials using clinical endpoints include objective definitions of "confirmed" and "probable," a formal reporting process with adequate information and supporting source documentation, evaluation by independent blinded reviewers, and procedures for adjudication.