CMV load acts as predictor of HIV progression
Study: Best treatment combines implant, cytovene
A study analyzing cytomegalovirus (CMV) viral load finds that the amount of CMV detected in the blood is a stronger predictor of disease progression and death than HIV RNA viral load. A second CMV study indicates that patients treated with an implant plus oral ganciclovir did better than those treated with the implant alone.
The first study, presented recently at the 35th Annual Conference of the Infectious Disease Society of America in San Francisco, showed that patients who tested positive for CMV through polymerase chain reaction (PCR) had a 3.4-fold greater likelihood of developing CMV disease, and a 2.5-fold greater risk of death compared to CMV-negative patients.
"The connection between CMV viral load and survival gives us important insight into the clinical risks of people with HIV/AIDS," said Stephen Spector, MD, lead investigator and assistant professor of medicine at the University of California, San Diego. "This knowledge can help guide treatment decisions that extend patient survival."
While CD4 counts had no correlation with disease progression, HIV RNA viral load did offer a predictive value for when patients would develop clinical CMV disease. However, CMV viral load was an even stronger predictor, Spector noted, adding that the study underscores the importance of CMV PCR testing for patients at risk for CMV.
The results were taken from 600 patients enrolled in the Roche 1654 study, a double-blind study comparing treatment with oral ganciclovir to placebo in patients treated with two nucleoside analogues. Overall, patients who were PCR-positive two months after the study began had a 48% risk of developing CMV disease, compared to a 20% risk for those who were PCR-negative, Spector reported.
Implant combination delays disease
New data presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Toronto in October indicate that combining the CMV retinitis implant, Vitrasert, with oral ganciclovir significantly reduces the incidence of CMV disease in other organs of the body and delays CMV onset in the unaffected eye. Also, patients given the combined treatment had slower progression to CMV disease in the implanted eye than those who relied on implants alone.
"This study is significant because it demonstrates that the best way to treat patients with CMV retinitis is to combine intense local therapy [implant] with systemic treatment [oral ganciclovir]," says Daniel Martin, MD, principal investigator in the study and associate professor of medicine at Emory University in Atlanta.
Patients on combination therapy also had a lower incidence of Kaposi’s sarcoma, required fewer hospitalizations, and had reduced incidence of new AIDS-associated conditions compared to those on implant alone.
The randomized trial, called GAN2304, enrolled 377 patients with unilateral (one eye only) CMV retinitis that was newly diagnosed or stable following intravenous ganciclovir. Patients were assigned to one of three arms implant, implant and oral ganciclovir, and intravenous ganciclovir. The median survival time was 568 days for those taking the combination, 426 days for those on intravenous ganciclovir, and 388 for those on implant alone.
In addition, after six months of treatment, 22% of patients in the combination group experienced new CMV disease, compared to 37% for those on implant alone. However, only 17% of those on intravenous ganciclovir had new CMV.
The study also found that patients who received protease inhibitors during the trial had a lower incidence of CMV disease. Indeed, the widespread use of protease inhibitors has contributed to a marked decline in the incidence of CMV disease.
A study evaluating the clinical and economic impact of the new drugs on CMV disease analyzed CD4 counts and CMV incidence in a Los Angeles AIDS practice from 1994 through 1996. The number of patients who had CD4 counts lower than 50 dropped from 1,420 to 1,290. The prevalence of CMV dropped from 51 to 16 cases, and the incidence fell from 5 cases to one case.
Total costs for CMV treatment at the facility for the period declined from $117,214 per month in 1994 to $32,326 in 1996. The researchers also noted that patients whose CD4 counts were previously below 50 and then rose above 50 after therapy did not appear to be at higher risk of CMV disease while on effective therapy, and may not require routine ophthalmological assessment.1
Reference
1. Ruane P, Zakowski P, Sokolov R, et al. Impact of new antiretroviral therapies on CMV disease, incidence, and cost. Presented at the meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy. Abstract No. N20. Toronto; 1997.
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