| 1. |
- Dorlo, Thomas P C, et al.
(author)
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Failure of miltefosine in visceral leishmaniasis is associated with low drug exposure.
- 2014
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In: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 0022-1899 .- 1537-6613. ; 210:1, s. 146-53
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Journal article (peer-reviewed)abstract
- BACKGROUND: Recent reports indicated high miltefosine treatment failure rates for visceral leishmaniasis (VL) on the Indian subcontinent. To further explore the pharmacological factors associated with these treatment failures, a population pharmacokinetic-pharmacodynamic study was performed to examine the relationship between miltefosine drug exposure and treatment failure in a cohort of Nepalese patients with VL.METHODS: Miltefosine steady-state blood concentrations at the end of treatment were analyzed using liquid chromatography tandem mass spectrometry. A population pharmacokinetic-pharmacodynamic analysis was performed using nonlinear mixed-effects modeling and a logistic regression model. Individual estimates of miltefosine exposure were explored for their relationship with treatment failure.RESULTS: The overall probability of treatment failure was 21%. The time that the blood concentration was >10 times the half maximal effective concentration of miltefosine (median, 30.2 days) was significantly associated with treatment failure: each 1-day decrease in miltefosine exposure was associated with a 1.08-fold (95% confidence interval, 1.01-1.17) increased odds of treatment failure.CONCLUSIONS: Achieving a sufficient exposure to miltefosine is a significant and critical factor for VL treatment success, suggesting an urgent need to evaluate the recently proposed optimal allometric miltefosine dosing regimen. This study establishes the first evidence for a drug exposure-effect relationship for miltefosine in the treatment of VL.
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| 2. |
- Rijal, Suman, et al.
(author)
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Increasing failure of miltefosine in the treatment of Kala-azar in Nepal and the potential role of parasite drug resistance, reinfection, or noncompliance.
- 2013
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In: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 56:11, s. 1530-8
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Journal article (peer-reviewed)abstract
- BACKGROUND: Miltefosine (MIL), the only oral drug for visceral leishmaniasis (VL), is currently the first-line therapy in the VL elimination program of the Indian subcontinent. Given the paucity of anti-VL drugs and the looming threat of resistance, there is an obvious need for close monitoring of clinical efficacy of MIL.METHODS: In a cohort study of 120 VL patients treated with MIL in Nepal, we monitored the clinical outcomes up to 12 months after completion of therapy and explored the potential role of drug compliance, parasite drug resistance, and reinfection.RESULTS: The initial cure rate was 95.8% (95% confidence interval [CI], 92.2-99.4) and the relapse rate at 6 and 12 months was 10.8% (95% CI, 5.2-16.4) and 20.0% (95% CI, 12.8-27.2) , respectively. No significant clinical risk factors of relapse apart from age <12 years were found. Parasite fingerprints of pretreatment and relapse bone marrow isolates within 8 patients were similar, suggesting that clinical relapses were not due to reinfection with a new strain. The mean promastigote MIL susceptibility (50% inhibitory concentration) of isolates from definite cures was similar to that of relapses. Although more tolerant strains were observed, parasite resistance, as currently measured, is thus not likely involved in MIL treatment failure. Moreover, MIL blood levels at the end of treatment were similar in cured and relapsed patients.CONCLUSIONS: Relapse in one-fifth of the MIL-treated patients observed in our study is an alarming signal for the VL elimination campaign, urging for further review and cohort monitoring.
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