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Remune may offer HAART-stopping option for chronic HIV patients

CARLSBAD, CA., Aug. 15, 2002 -- Indicating for the first time in a clinical trial that Remune might give relief for HIV-infected patients from the adverse side effects of antiretroviral therapies, The Immune Response Corporation announced results from an ongoing study by the Canadian HIV Trials Network (CTN-140 trial), which examined the effects of stopping HAART (Highly Active Antiretroviral Therapy) in adults with chronic HIV infection.

"With the growing number of studies indicating that HIV-infected patients are developing greater resistance and significant adverse side-effects to the battery of antiretroviral drugs available today, the results from this study suggest that treatment strategies using Remune might give their systems the break from drug therapies they need to recover," said Dr. Emil Toma, principal investigator of the trial and a professor at University of Montreal and active staff at Hotel-Dieu du Centre Hospitalier de l'Universite de Montreal (CHUM).

"With this study, we can further develop possible therapeutic approaches designed to give patients a break from antiretrovirals while controlling viral load and boosting the immune system."

The study, conducted over 116 weeks and still ongoing, involved ten adults with a median age of 41 and ranging from 36 to 51 years of age. All had chronic HIV infection and were on HAART for a median of 2.7 years, with HIV RNA levels (VL) below detection limit (<50 HIV-1 RNA copies/ml) for a median of two years and median CD4+ T cell count of 385/ml prior to antiretroviral treatment interruption.

After HAART intensification with ddI, GM-CSF, hydroxyurea, and initiation of therapeutic vaccination with Remune, patients stopped antiretrovirals, but continued to receive Remune every three months. To date, each participant in the study has received nine doses of Remune.

"In chronically HIV-infected adults, HAART results in significant clinical and immunologic benefits, but even prolonged suppression of HIV replication does not prevent viral rebound when antiretrovirals are stopped," Dr. Toma said.

"We reasoned that intensification of an already optimal HAART (meaning patients with HIV viral loads below detection limit) with ddI to better fight the HIV in resting cells, hydroxyurea to diminish cell activation and to boost the activity of ddI, GM-CSF to increase the activity of antiretrovirals in reservoirs such as macrophages, and initiation of a therapeutic HIV vaccine (Remune) prior to stopping antiretrovirals, might lead to a partial containment of viremia allowing for long periods without recourse to HAART."

Evaluations taken during the study included: clinical, virologic (viral load, HIV genotype, sensitive cultures), immunologic (lymphocyte phenotyping, serum cytokines/chemokines, Interferon-alpha (IFN-alpha) Elispot, intracellular cytokine staining for IFN-alpha secretion from CD4+ and CD8+ T cells, lymphoproliferative responses, thymus CT-Scans), health-related quality-of-life, and nutrition.

"One patient has been off therapy for 88 weeks, having not resumed HAART since first stopping and another was off therapy for 44 weeks after the second interruption," Dr. Toma said. "The other participants stayed off HAART for an average of 16 weeks after the first interruption and for an average of 24 weeks after the second interruption. It appears that at each subsequent interruption there was a statistically significant decrease in the peak viral load rebound and this was associated with an increased magnitude and breadth of the HIV specific immune responses.

"Also, with each treatment interruption, the time to attain the peak viral load increased and patients responded more quickly to HAART once it was re- initiated, " Dr. Toma added. "These chronically infected patients behaved like primary infection patients where partial control of virus is associated with HIV specific immunity. For the 40 million people around the world currently infected with this deadly disease, this study offers hope for another possible treatment option using Remune."

The data was presented at the recent 2002 Federation of American Societies for Experimental Biology (FASEB) Meeting on Therapeutic and Preventive AIDS Vaccines in Tucson, Arizona.

Participating in the Canadian trial were Hotel-Dieu du CHUM, McGill Research Centre, and Ste-Justine Hospital, all of Montreal, Quebec, and the Canadian HIV Trials Network (CTN) in Vancouver, B.C.

Posted: August 2002