Hydroxyurea and HIV-1 viraemia

Systematic review of combination antiretroviral therapy with didanosine plus hydroxyurea: a partial solution to Africa's HIV/AIDS problem?

Effective antiretroviral therapy remains beyond the reach of most human immunodeficiency virus (HIV)-infected persons living in the third world because of its tremendous cost. The cancer drug, hydroxyurea, inhibits HIV-1 replication in vitro and, when combined with didanosine (ddI), results in significant antiretroviral synergy. In vivo, hydroxyurea specifically targets quiescent lymphocytes and macrophages, important cellular reservoirs for HIV-1, and the combination of ddI plus hydroxyurea effectively reduces plasma HIV-1 RNA levels. Combination ddI-hydroxyurea costs about one-eighth as much as currently recommended triple drug combinations, and several countries in Africa are exploring the feasibility of widescale use of ddI-hydroxyurea for their HIV-infected populations. Intrigued by its potential relevance for Africa, the authors reviewed the literature on the in vitro and clinical efficacy of ddI plus hydroxyurea against HIV. The combination of ddI plus hydroxyurea is an effective and potentially more affordable regimen for HIV-infected persons living in poorer countries.

Hydroxyurea in the treatment of HIV-1

OBJECTIVE

To describe the role of hydroxyurea in the treatment of HIV-1.

DATA SOURCES

Published clinical studies using hydroxyurea in HIV treatment were accessed through MEDLINE (January 1994-March 1999) and conference abstracts. All relevant studies were evaluated.

DATA SYNTHESIS

Adherence, expense, and resistance limit the pharmacotherapeutic options in the management of patients with HIV. Hydroxyurea may be an alternative to conventional HIV treatments.

CONCLUSIONS

Several potential advantages of adding hydroxyurea to antiretroviral treatment regimens include the drug's well-documented toxicity, convenient dosing, good tolerability and low cost, and its unique mechanism of action. Hydroxyurea may have synergistic effects that prove promising in initial and salvage therapy antiretroviral regimens. Larger, well-controlled clinical studies are needed to adequately define the role of hydroxyurea in the treatment of HIV.

Hydroxyurea to inhibit human immunodeficiency virus-1 replication

Treatment of human immunodeficiency virus (HIV) infection continues to be a challenge. Drug regimens that include two nucleoside reverse transcriptase inhibitors and a protease inhibitor are now the standard of care. These regimens require strict patient adherence and have numerous adverse effects at a high cost, so clinicians must continue to explore other therapeutic options. Hydroxyurea is a ribonucleotide reductase inhibitor that may have efficacy against HIV. We conducted a critical review of the literature to examine the utility of hydroxyurea-based drug combinations.

A placebo-controlled trial of didanosine plus stavudine, with and without hydroxyurea, for HIV infection. The Swiss HIV Cohort Study

OBJECTIVE

To explore the short-term effects on surrogate markers for HIV progression of didanosine (ddl) plus stavudine (d4T), with or without hydroxyurea.

DESIGN

Randomized, double-blinded, prospective study.

SETTING

Swiss HIV Cohort Study.

PATIENTS

A total of 144 patients (75% antiretroviral-naive) were studied (mean baseline HIV-1 RNA, 4.53 log10 copies/ml; mean CD4 cell count, 370 x 10(6)/l).

INTERVENTION

Patients received ddl (200 mg twice daily) plus d4T (40 mg twice daily), with additional hydroxyurea (500 mg twice daily) or placebo.

MAIN OUTCOME MEASURES

The primary endpoint was a reduction of viraemia below 200 copies/ml after 12 weeks. At that time, patients who did not reach the primary endpoint were withdrawn in the hydroxyurea arm, whereas patients in the placebo group had the option of adding hydroxyurea to ddl and d4T. All patients were followed until week 24.

RESULTS

After 12 weeks, 54% of the patients randomized to hydroxyurea had viraemia below 200 copies/ml, compared with 28% on placebo (P < 0.001). Using an ultrasensitive assay with a limit of detection of 20 copies/ml, 19% of patients receiving hydroxyurea had viraemia levels below 20 copies/ml, compared with 8% on placebo (P = 0.05). Mean decrease in HIV-1 RNA was 2.3 and 1.7 log10 copies/ml for hydroxyurea and placebo groups, respectively (P = 0.001). Hydroxyurea was found to induce lymphopenia (-124 x 10(6)/l). Increase in CD4 cell counts was +28 x 10(6)/l during hydroxyurea treatment compared with +107 x 10(6)/l on placebo (P = 0.001).

CONCLUSIONS

Hydroxyurea improved the antiviral activity of d4T and ddl over a 12-week period, but was associated with a smaller increase in CD4 cell counts due to hydroxyurea-induced lymphopenia.