AEGiS-CATIE: ANTI-HIV AGENTS: Ritonavir -- effect on survival

ANTI-HIV AGENTS: Ritonavir -- effect on survival

TreatmentUpdate 70, Volume 8, No 6; September, 1996
Sean Hosein

Researchers randomly assigned over 1,000 subjects to receive ritonavir 600 mg twice daily or fake ritonavir (placebo). All subjects had less than 101 CD4+ cells, the average ranging from 30 to 35 cells. After 4 months, subjects receiving placebo could switch to ritonavir if they developed new life-threatening complications or renewed attacks of old infections, specifically:

* PCP

* ulcers due to herpes viruses

* yeast infections in the mouth and throat

Subjects were allowed to continue taking whatever drugs they were using before entering this study. Indeed, half the subjects were taking 14 other drugs.

Who survived?

By the 6th month of the study, researchers found that roughly

* 4% of subjects on ritonavir

* 8% of subjects on placebo

had died. This difference was statistically significant; that is, not likely due to chance alone.

Extracting meaning from numbers

It is difficult to assess the impact of ritonavir over the long term because after 4 months, subjects who developed serious complications were allowed to use ritonavir. Moreover, another study found that ritonavir improved the ability of T cells to respond to infections during the first month of therapy. After this time, T cell function declined to its pre-ritonavir level. Nearly one year into the study researchers reported the following events:

Event Ritonavir Placebo

Death 27 35

Yeast infections (oral) 18 41

Kaposi's sarcoma 8 20

PCP 10 22

CMV retinitis 18 17

Wasting syndrome 2 8

HIV and CD4+ cell counts

Some subjects who received ritonavir had an increase of at least 50 CD4+ cells that was sustained for about one year. After receiving ritonavir for 2 weeks, the amount of HIV in the blood fell to 1/10th its pre-study level.

Toxicity

Subjects receiving ritonavir experienced diarrhea, tingling around the mouth (both inside and outside) and nausea. Gradually increasing the dose of ritonavir over a period of 10 days, starting with 600 mg/day, may increase patients' tolerance of the drug.

REFERENCES:

1. Cameron DW, Heath-Chiozzi M, Kravick S, et al. Prolongation of life and prevention of complications in advanced HIV immunodeficiency with ritonavir: update. Mo.B.411.

2. Pakker NG, Roos MTL, de Jong M, et al. Analyses of T cell repopulation and restoration of T cell function during therapy with different antiretrovirals. We.B.291.

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Always watch for outdated information. This article first appeard in 1996. This material is designed to support, not replace, the relationship that exists between you and your doctor.

Copyright © 1996 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284 http://www.catie.ca

This information is designed to support, not replace, the relationship that exists between you and your doctor.
©1996. AEGIS.