Highly active antiretroviral treatment

Kaposi sarcoma (KS) - an angiogenic-inflammatory neoplasm - is the most prevalent cancer in HIV-infected patients and its appearance is preceded by infection with human Heipesvitus-8 (HHV-8). Although chemotherapy has become the treatment of choice approved by the FDA, there are also good response rates in patients treated with IFN-a. Fortunately, today highly active antiretroviral therapy (HAART) has dramatically decreased the incidence of KS in AIDS patients. 

So far, five different protease inhibitors have been approved by the FDA for the treatment of HIV infection [3, 4]. Clinical trials in which protease inhibitors were evaluated in monotherapy demonstrated the potency of this class of inhibitors (decrease in HIV RNA levels, increase in CD4 cell counts). Treatment regimens were subsequently broadened to include reverse transcriptase inhibitors in combination with protease inhibitors. The result of these clinical trials has led to a list of guidelines with recommendations for the optimal treatment options. Prolonged control of the infection with combination therapy (highly active antiretroviral therapy, HAART ) could be shown. 

Kimura H (2002) Cost of HIV treatment in highly active antiretroviral therapy in Japan, Nippon Rinsho 60(4) 813-816... 

These properties of Enterosgel are of great interest for treatment of HIV-infected patients. In Table 21.9 the preliminary results of Enterosgel use for treatment of diarrheic syndrome in HIV-infected patients treated with highly active antiretroviral therapy are presented [87]. 

Soon after the introduction of highly active antiretroviral combination treatments (HAART), lipodystrophy was associated with the use of protease inhibitors, and several reports have confirmed that a syndrome of peripheral lipodystrophy, central adiposity, breast hypertrophy in women, hyperlipidemia, and insulin resistance with hyperglycemia is an adverse event associated with the use of potent combination antiretroviral therapy, particularly including HIV-1 protease inhibitors (982-987). 

The advent of highly active antiretroviral therapy (HAART) to minimize the rapid development of viral resistance in the treatment of HIV infection may result in multiple drug interactions (110-113). Both the nonnucleoside reverse transcriptase inhibitors and the protease inhibitors are substrates and inhibitors of some CYP enzymes, and some act as inducers as well (110,111). The major effects are on the CYP3A isoforms, and this has been used to advantage to increase concentrations of some HIV drugs. For example, delavirdine is a mechanism-based irreversible inhibitor of CYP3A4, and thereby is used to increase exposure to protease inhibitors (114). Ritonavir is a protease inhibitor, but it is used primarily for its ability as a potent inhibitor of CYP3A4 to increase concentrations of other protease inhibitors (115). 

The efficacy and safety of abacavir (NRTI) and efavirenz (NNRTI) plus background therapy have been retrospectively evaluated in 50 patients, who had previously been treated with highly active antiretroviral therapy (HAART) (4). There was some immunological benefit, albeit limited, in most of the patients. Adverse effects were not mentioned in detail, but the dropout rate during the first 4 weeks of treatment was high, owing to skin rashes and hypersensitivity reactions. 

Successful treatment of human immunodeficiency virus (HIV-1) infection has been achieved through successful implementation of highly active antiretroviral therapy, frequently referred to as HAART. This involves simultaneous administration of both nucleoside and nonnucleoside reverse transcriptase inhibitors and one or more protease inliibitors. The common nucleoside reverse transcriptase inhibitors are the thymidine analogs didanosine (ddl), lamivudine (3TC), and zalcitabine (ddC) and the non-thymidine analogs abacavir (Ziazen), stavudine (d4T), and zidovudine (AZT). The nonnucleoside reverse transcriptase inhibitors include delavirdine, efavirenz, and nevirapine. The protease inhibitors include indinavir, nelfinavir, ritonavir, and saquinavir. Response to therapy is monitored by quantification of HIV-RNA copies (viral load) and CD-4+ T-lymphocyte count. Successful therapy is indicated when viral load is reduced to <50 copies/mL and CD-4+ count >500 per mL. 

The treatment of patients with AIDS-associated lymphomas is difficult because the immunocompromised state of these patients increases their risk of significant toxicity due to myelosuppressive therapy. Except for primary CNS lymphoma, AIDS-related lymphoma is never considered truly localized, and systemic chemotherapy is indicated. For patients with adequate immune function and without a history of an opportunistic infection, chemotherapy regimens similar to those used for aggressive lymphomas may be used. " However, many patients with AIDS-related lymphoma are treated with less intensive regimens because of the increased risk of treatment-related toxicity. In the era of highly active antiretroviral therapy (HAART), however, some clinicians believe that standard doses of chemotherapy can be safely administered to patients who achieve a virologic response to HAART. 

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