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In recent years, scientists have shown that drug-resistant strains of HIV can be transmitted and that drug-resistant virus can reduce rates of virologic suppression when combination therapy is administered. Genotype resistance testing, when performed prior to the initiation of antiretroviral therapy, "can lead to selection of a more effective initial antiretroviral regimen and likely longer survival for patients who have drug-resistant virus" (p. 1320). Nevertheless, there has been a "hesitation to employ resistance testing for all individuals with new diagnoses ... [based on] multiple factors, most notably the cost of the test and the absence of controlled data showing that this testing strategy improves outcomes" (p. 1320). To explore this reasoning, Sax et al. (2005) modeled "the clinical impact and cost-effectiveness of genotype resistance testing for treatment-naive patients with chronic HIV infection" (p. 1316) in a hypothetical cohort of such patients and found that "the cost-effectiveness remained favorable through wide variations in baseline assumptions, including variations in genotype cost, prevalence of resistance overall and to individual drug classes, and sensitivity of resistance testing" (p. 1316). "On the basis of the available evidence, and considering both clinical benefits and costs," Sax and colleagues conclude that "genotype resistance testing should be performed for all patients with newly diagnosed HIV infection in the United States, with the results used to guide the choice of antiretroviral regimen when treatment is indicated" (p. 1322).
With regard to antiretroviral regimens, on October 28, the U.S. Food and Drug Administration (FDA)
approved a new formulation of Kaletra. Kaletra (lopinavir/ritonavir) is now available as a film coated tablet (200mg/50mg) that provides advantages over the currently marketed capsule formulation for HIV-1 infected patients. Specifically, the tablet formulation: does not require refrigeration[;] can be administered without regard to meals[;] does not require dose adjustments for concomitant use with certain ... [antiretrovirals] in treatment-naïve patients[; and] has a decreased pill burden compared to the capsule formulation (2 tablets twice daily or 4 tablets once daily in treatment-naïve patients only vs 3 capsules twice daily or 6 capsules once daily in treatment-naïve patients only). (FDA, 2005)
To better characterize the severity and longevity of side effects associated with the use of efavirenz (EFV or Sustiva®), Clifford et al. (2005) conducted a randomized, controlled study involving 303 adults living with HIV, 200 of whom received regimens including EFV. The investigators found that recipients of EFV were more likely to discontinue their prescribed regimen because of neurological or psychological complications than those who did not receive EFV. Additionally, recipients of EFV reported more sleep disturbances and "bad dreams" during their first week on an EFV-based regimen than those not receiving EFV. Importantly, no significant differences in depression, anxiety, sleep disturbance, cognitive performance, or neurological symptoms were found between these two groups at weeks 4, 12, and 24. More than 80% of participants in both groups, however, reported anxiety symptoms throughout the study. Clifford and colleagues conclude that their findings support
current recommendations regarding [EFV] use: Transient, subjective neurologic effects are frequently experienced but are generally not severe, and forewarned patients may safely continue the drug and anticipate that the symptoms will resolve promptly. Initiation of any therapy for HIV infection, together with the stresses of living with a serious chronic illness, require[s] careful patient monitoring and support, including recognition of substantial anxiety and depression. [EFV], however, does not need to be avoided as a treatment for patients who are experiencing significant anxiety or depression. (p. 720)
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Winter 2006 Newsletter / Volume 7, Issue 2
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