Efficacy of indinavir–ritonavir-based regimens in HIV-1-infected patients with prior protease inhibitor failures

Campo, Rafael; Moreno, Jose N.; Suárez, Germán Pérez; Miller, Nancimae; Kolber, Michael A.; Holder, Daniel; Shivaprakash, Malathi; DeAngelis, Dana M; Wright, J. L.; Schleif, William A.; Emini, Emilio A.; Condra, Jon H.

doi:10.1097/00002030-200309050-00012

Cited by 9 publications

(6 citation statements)

References 38 publications

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“…We have also reported preliminary findings suggesting that resistance is uncommon in treated individuals with poor adherence, and we have hypothesized that poor adherence leads to insufficient drug pressure to select for resistant virus 36,41 . Other recent studies also suggest that low adherence levels may not lead to the development of drug resistance 42,43 . The current finding that resistance is less common in a population with marginal adherence is consistent with this hypothesis, and suggests that, unlike the case with tuberculosis, marginalized populations may not be at greater risk for HIV antiretroviral resistance due to poor adherence.…”

Section: Discussionmentioning

confidence: 98%

Prevalence of antiretroviral drug resistance in the HIV-1-infected urban indigent population in San Francisco: a representative study

et al. 2004

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We determined the prevalence of antiretroviral (ARV) resistance in HIV-1 infected indigent persons in San Francisco, California. Three hundred and twenty-seven subjects (159 (49%) ARV naïve, and 168 (51%) ARV-experienced), were recruited during 1996-97 and 1999-2000. Plasma HIV-1 viral load quantification and genotypic resistance testing were performed. Twice as many subjects received nucleoside reverse transcriptase inhibitors (NRTIs) as non-nucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs); resistance mutation prevalences were 30%, 14% and 16% respectively. Risk of any resistance mutations was strongly and independently associated with prior ARV exposure (OR = 1.3 per year of exposure, P < 0.0001) and with ARV exposure prior to HAART (OR = 2.5, P = 0.015). Prevalences of primary ARV resistance mutations among both treatment-naive and treatment-experienced subjects in this indigent urban population are low compared to other observational cohorts, are directly related to length and type of prior ARV exposure, and did not increase significantly between recruitment periods.

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Section: Discussionmentioning

confidence: 98%

Prevalence of antiretroviral drug resistance in the HIV-1-infected urban indigent population in San Francisco: a representative study

et al. 2004

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“…In a study 30 of 20 treatment-experienced recipients of indinavir at 800 mg twice per day plus ritonavir at 100 or 200 mg twice per day, the L90M mutation was identified in nonresponders and partial respondents but not in responders, despite more consistent through levels, as compared with standard indinavir dosing. On the contrary, another study by Campo et al 31 suggested that short-term virological suppression (HIV RNA level, < 400 copies/mL) is possible for subjects with previous failure of PI-based treatment with phenotypic resistance to indinavir when treated with indinavir plus ritonavir at 800 mg and 200 mg twice per day. These results demonstrated how the same dose change can result in lower rates of resistance.…”

Section: Discussionmentioning

confidence: 96%

Analysis of possible drug-drug interactions between ritonavir and other antiretrovirals in a section of the private health care sector in South Africa

Katende-Kyenda

Lubbe

Serfontein

et al. 2009

Afr. j. prim. health care fam. med.

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BackgroundThe introduction of human immunodeficiency virus (HIV) protease inhibitors (PIs) has led to a dramatic decline in the morbidity and mortality associated with HIV infection. However, the concomitant use of PIs and other antiretrovirals (ARVs) can be complicated by drug-drug interactions (DDIs), adversely affecting levels of PIs.MethodA quantitative, retrospective drug utilisation study was performed using data obtained from the medicine claims database of a pharmacy benefit management company during 2004, 2005 and 2006. The possible DDIs found among ARVS themselves were identified using the classification by Tatro.ResultsThe percentage of ARV prescriptions claimed of the total number of medicine items increased from 1.68% (n = 43 482) during 2004 to 3.18% (n = 51 613) during 2005, then to 4.74% (n = 47 085) during 2006. A total of 1 326, 1 863 and 960 possible DDIs were identified among ARVs themselves for 2004, 2005 and 2006 respectively. Of these, ritonavir (unboosted or boosted) presented with the most possible DDIs, accounting for 74.28% (n = 985) for 2004; 67.90% (n = 1 265) for 2005; and 27.50% (n = 264) for 2006. The highest prevalence of DDIs identified was between ritonavir (unboosted) and saquinavir (n = 974, 5) for 2005 and 2006; followed by indinavir (n = 490, 129, 155) for 2004 to 2006; and efavirenz (n = 274) for only 2004; then ritonavir (boosted), co-formulated as lopinavir/ritonavir, and efavirenz (n = 118, 88, 34) for 2004 to 2006; nevirapine (n = 49, 37) for 2004 and 2005; indinavir (n = 9) for 2004; and saquinavir (n = 22) for 2006.ConclusionThese findings indicate that concomitant use of PIs such as ritonavir, a potent cytochrome P450(CYP)3A4 enzyme inhibitor, and other ARVs is complicated by possible DDIs and therefore further studies need to be done on the ARV combinations and management of these DDIs.

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“…Studies performed to date include small, nonrandomized patient cohorts and lack appropriate control for baseline drug resistance to reliably assess response. [10][11][12][13] In vitro susceptibility studies 14 predict that indinavir enhancement with ritonavir will produce concentrations that exceed inhibitory concentrations for resistant isolates; however, virologic benefit remains to be confirmed clinically.…”

Section: Clinical Trialsmentioning

confidence: 99%

Low-Dose Ritonavir for Protease Inhibitor Pharmacokinetic Enhancement

Rathbun

Rossi

2002

Ann Pharmacother

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Efficacy of indinavir–ritonavir-based regimens in HIV-1-infected patients with prior protease inhibitor failures

Abstract: These results suggest that IDV-RTV-based regimens may be able to overcome IDV resistance. This underscores the importance of drug adherence, potency, and exposure in determining virologic responses to antiretroviral therapy.

Cited by 9 publications

References 38 publications

Prevalence of antiretroviral drug resistance in the HIV-1-infected urban indigent population in San Francisco: a representative study

Prevalence of antiretroviral drug resistance in the HIV-1-infected urban indigent population in San Francisco: a representative study

Analysis of possible drug-drug interactions between ritonavir and other antiretrovirals in a section of the private health care sector in South Africa

Low-Dose Ritonavir for Protease Inhibitor Pharmacokinetic Enhancement

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