Browsing by Author "Buzibye, Allan"
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Item Antiretroviral concentration measurements as an additional tool to manage virologic failure in resource limited settings: a case control study(AIDS research and therapy, 2019) Buzibye, Allan; Musaazi, Joseph; Braun, Amrei von; Nanzigu, Sarah; Sekaggya‑Wiltshire, Christine; Kambugu, Andrew; Fehr, Jan; Lamorde, Mohammed; Gutteck, Ursula; Muller, Daniel; Sowinski, Stefanie; Reynolds, Steven J.; Castelnuovo, BarbaraSeveral studies demonstrate a correlation between sub-therapeutic concentrations of antiretroviral drugs and virologic failure. We examined the sensitivity, specificity and predictive values of sub-therapeutic drug levels in predicting viralogic failure. Methods: This was a case control study with cases being samples of participants with virologic failure, and controls samples of participants with virologic suppression. We analyzed samples obtained from participants that had been on antiretroviral treatment (ART) for at least 6 months. Virologic failure was defined as HIV-RNA viral load ≥ 1000 copies/ ml. Sub-therapeutic drug levels were defined according to published reference cutoffs. The diagnostic validity of drug levels for virologic failure was assessed using plasma viral loads as a gold standard. Results: Sub-therapeutic ART concentrations explained only 38.2% of virologic failure with a probability of experiencing virologic failure of 0.66 in a patient with low drug levels versus 0.25 for participants with measurements within or above the normal range. Approximately 90% of participants with ART concentrations above the lower clinical cut off did not have virologic failure. Conclusions: These results support prior indication for therapeutic drug monitoring in cases of suspected virologic failure.Item Building clinical pharmacology laboratory capacity in low- and middle-income countries: Experience from Uganda(African Journal of Laboratory Medicine, 2023) Omali, Denis; Buzibye, Allan; Kwizera, Richard; Byakika-Kibwika, Pauline; Namakula, Rhoda; Matovu, Joshua; Mbabazi, Olive; Mande, Emmanuel; Sekaggya-Wiltshire, Christine; Nakanjako, Damalie; Gutteck, Ursula; McAdam, Keith; Easterbrook, Philippa; Kambugu, Andrew; Fehr, Jan; Castelnuovo, Barbara; Manabe, Yukari C.; Lamorde, Mohammed; Mueller, Daniel; Merry, ConceptaResearch and clinical use of clinical pharmacology laboratories are limited in low- and middle-income countries. We describe our experience in building and sustaining laboratory capacity for clinical pharmacology at the Infectious Diseases Institute, Kampala, Uganda. Intervention: Existing laboratory infrastructure was repurposed, and new equipment was acquired. Laboratory personnel were hired and trained to optimise, validate, and develop in-house methods for testing antiretroviral, anti-tuberculosis and other drugs, including 10 high-performance liquid chromatography methods and four mass spectrometry methods. We reviewed all research collaborations and projects for which samples were assayed in the laboratory from January 2006 to November 2020. We assessed laboratory staff mentorship from collaborative relationships and the contribution of research projects towards human resource development, assay development, and equipment and maintenance costs. We further assessed the quality of testing and use of the laboratory for research and clinical care. Lessons learnt: Fourteen years post inception, the clinical pharmacology laboratory had contributed significantly to the overall research output at the institute by supporting 26 pharmacokinetic studies. The laboratory has actively participated in an international external quality assurance programme for the last four years. For clinical care, a therapeutic drug monitoring service is accessible to patients living with HIV at the Adult Infectious Diseases clinic in Kampala, Uganda. Recommendations: Driven primarily by research projects, clinical pharmacology laboratory capacity was successfully established in Uganda, resulting in sustained research output and clinical support. Strategies implemented in building capacity for this laboratory may guide similar processes in other low- and middle-income countries.Item Cohort profile of a study on outcomes related to tuberculosis and antiretroviral drug concentrations in Uganda: design, methods and patient characteristics of the SOUTH study(BMJ open, 2017) Sekaggya-Wiltshire, Christine; Castelnuovo, Barbara; Braun, Amrei von; Musaazi, Joseph; Muller, Daniel; Buzibye, Allan; Gutteck, Ursula; Henning, Lars; Ledergerber, Bruno; Corti, Natascia; Lamorde, Mohammed; Fehr, Jan; Kambugu, AndrewTuberculosis (TB) is a leading cause of death among people living with HIV in sub-Saharan Africa. Several factors influence the efficacy of TB treatment by leading to suboptimal drug concentrations and subsequently affecting treatment outcome. The aim of this cohort is to determine the association between anti-TB drug concentrations and TB treatment outcomes. Participants Patients diagnosed with new pulmonary TB at the integrated TB-HIV outpatient clinic in Kampala, Uganda, were enrolled into the study and started on firstline anti-TB treatment. Findings to date Between April 2013 and April 2015, the cohort enrolled 268 patients coinfected with TB/HIV ; 57.8% are male with a median age of 34 years (IQR 29–40). The median time between the diagnosis of HIV and the diagnosis of TB is 2 months (IQR 0–22.5). The majority of the patients are antiretroviral therapy naive (75.4%). Our population is severely immunosuppressed with a median CD4 cell count at enrolment of 163 cells/μL (IQR 46–298). Ninety-nine per cent of the patients had a diagnosis of pulmonary TB confirmed by sputum microscopy, Xpert/RIF or culture and 203 (75.7%) have completed TB treatment with 5099 aliquots of blood collected for pharmacokinetic analysis. Future plans This cohort provides a large database of well-characterised patients coinfected with TB/HIV which will facilitate the description of the association between serum drug concentrations and TB treatment outcomes as well as provide a research platform for future substudies including evaluation of virological outcomes.Item Decreased Dolutegravir and Efavirenz Concentrations With Preserved Virological Suppression in Patients With Tuberculosis and Human Immunodeficiency Virus Receiving High-Dose Rifampicin(Clinical Infectious Diseases, 2022) Sekaggya-Wiltshire, Christine; Nabisere, Ruth; Musaazi, Joseph; Otaalo, Brian; Aber, Florence; Alinaitwe, Lucy; Nampala, Juliet; Najjemba, Letisha; Buzibye, Allan; Omali, Denis; Gausi, Kamunkhwala; Kengo, Allan; Lamorde, Mohammed; Aarnoutse, Rob; Denti, Paolo; Dooley, Kelly E.; Sloan, Derek J.Higher doses of rifampicin may improve treatment outcomes and reduce the duration of tuberculosis (TB) therapy. However, drug–drug interactions with antiretroviral therapy (ART) and safety in people with human immunodeficiency virus (HIV) have not been evaluated. Methods. This was a randomized, open-label trial where newly diagnosed TB patients were randomized to higher (35 mg/kg) or standard (10 mg/kg) daily-dose rifampicin. ART treatment–naive patients were randomized to dolutegravir- or efavirenz-based ART. At week 6, trough dolutegravir or mid-dose efavirenz plasma concentrations were assayed. HIV viral load was measured at week 24. Results. Among 128 patients randomized, the median CD4 count was 191 cells/mm3. The geometric mean ratio (GMR) for trough dolutegravir concentrations on higher- vs standard-dose rifampicin was 0.57 (95% confidence interval [CI], .34–.97; P =.039) and the GMR for mid-dose efavirenz was 0.63 (95% CI, .38–1.07; P= .083). There was no significant difference in attainment of targets for dolutegravir trough or efavirenz mid-dose concentrations between rifampicin doses. The incidence of HIV treatment failure at week 24 was similar between rifampicin doses (14.9% vs 14.0%, P= .901), as was the incidence of drug-related grade 3–4 adverse events (9.8% vs 6%). At week 8, fewer patients remained sputum culture positive on higherdose rifampicin (18.6% vs 37.0%, P =.063). Conclusions. Compared with standard-dose rifampicin, high-dose rifampicin reduced dolutegravir and efavirenz exposures, but HIV suppression was similar across treatment arms. Higher-dose rifampicin was well tolerated among people with HIV and associated with a trend toward faster sputum culture conversion.Item Delayed Sputum Culture Conversion in Tuberculosis– Human Immunodeficiency Virus–Coinfected Patients With Low Isoniazid and Rifampicin Concentrations(Clinical Infectious Diseases, 2018) Sekaggya-Wiltshire, Christine; Braun, Amrei von; Lamorde, Mohammed; Ledergerber, Bruno; Buzibye, Allan; Henning, Lars; Musaazi, Joseph; Gutteck, Ursula; Denti, Paolo; Kock, Miné de; Jetter, Alexander; Byakika-Kibwika, Pauline; Eberhard, Nadia; Matovu, Joshua; Joloba, Moses; Muller, Daniel; Manabe, Yukari C.; Kamya, Moses R.; Corti, Natascia; Kambugu, Andrew; Castelnuovo, Barbara; Fehr2, Jan S.The relationship between concentrations of antituberculosis drugs, sputum culture conversion, and treatment outcome remains unclear. We sought to determine the association between antituberculosis drug concentrations and sputum conversion among patients coinfected with tuberculosis and human immunodeficiency virus (HIV) and receiving first-line antituberculosis drugs. Methods. We enrolled HIV-infected Ugandans with pulmonary tuberculosis. Estimation of first-line antituberculosis drug concentrations was performed 1, 2, and 4 hours after drug intake at 2, 8, and 24 weeks of tuberculosis treatment. Serial sputum cultures were performed at each visit. Time-to-event analysis was used to determine factors associated with sputum culture conversion. Results. We enrolled 268 HIV-infected patients. Patients with low isoniazid and rifampicin concentrations were less likely to have sputum culture conversion before the end of tuberculosis treatment (hazard ratio, 0.54; 95% confidence interval, .37–.77; P = .001) or by the end of follow-up (0.61; .44–.85; P = .003). Patients in the highest quartile for area under the rifampicin and isoniazid concentration-time curves for were twice as likely to experience sputum conversion than those in the lowest quartile. Rifampicin and isoniazid concentrations below the thresholds and weight <55 kg were both risk factors for unfavorable tuberculosis treatment outcomes. Only 4.4% of the participants had treatment failure. Conclusion. Although low antituberculosis drug concentrations did not translate to a high proportion of patients with treatment failure, the association between low concentrations of rifampicin and isoniazid and delayed culture conversion may have implications for tuberculosis transmission.Item High efavirenz serum concentrations in TB/HIV-coinfected Ugandan adults with a CYP2B6 516 TT genotype on anti-TB treatment(Journal of Antimicrobial Chemotherapy, 2019) Braun, Amrei von; Castelnuovo, Barbara; Ledergerber, Bruno; Cusato, Jessica; Buzibye, Allan; Kambugu, Andrew; Fehr, Jan; Calcagno, Andrea; Lamorde, Mohammed; Sekaggya-Wiltshire, ChristineTo report the efavirenz serumconcentrations in TB/HIV-coinfected Ugandan adults on concomitant anti-TB treatment and analyse factors associated with elevated concentrations in this specific population. Methods: Serum efavirenz concentrations in TB/HIV-coinfected Ugandan adults on efavirenz-based ART (600mg daily) were measured onsite at 2, 8, 12 and 24 weeks of concomitant anti-TB treatment, including rifampicin. Genetic analysis was done retrospectively through real-time PCR by allelic discrimination (CYP2B6 516G.T, rs3745274). Univariable and multivariable logistic regression analyses were done to assess factors potentially associated with elevated efavirenz serum concentrations. Results: A total of 166 patients were included in the analysis. The median age was 34 (IQR"30–40) years, 99 (59.6%) were male, the median CD4 cell count was 195 (IQR"71–334) cells/mm3 and the median BMI was 19 (IQR"17.6–21.5) kg/m2. Almost half of all patients (82, 49.4%) had at least one efavirenz serum concentration above the reference range of 4 mg/L. The serum efavirenz concentrations of patients with genotype CYP2B6 516 TT were consistently above 4 mg/L and significantly higher than those of patients with GG/GT genotypes: CYP2B6 516 TT 9.6 mg/L (IQR"7.3–13.3) versus CYP2B6 516 GT 3.4 mg/L (IQR"2.1–5.1) and CYP2B6 516 GG 2.6 mg/L (IQR"1.3–4.0) (Wilcoxon rank-sumtest: P,0.0001). Conclusions: A large proportion of our study participants had at least one efavirenz serum concentration .4 mg/L. The CYP2B6 516 TT genotype was the strongest predictor of high concentration. Physicians should be vigilant that efavirenz serum concentrations may be elevated in patients on concomitant anti-TB treatment and that individualized care is warranted whenever possible.Item High-Dose Oral and Intravenous Rifampicin for the Treatment of Tuberculous Meningitis in Predominantly Human Immunodeficiency Virus (HIV)-Positive Ugandan Adults: A Phase II Open-Label Randomized Controlled Trial(Clinical Infectious Diseases, 2021) Cresswell, Fiona V.; Meya, David B.; Kagimu, Enock; Grint, Daniel; Brake, Lindsey te; Kasibante, John; Martyn, Emily; Rutakingirwa, Morris; Quinn, Carson M.; Okirwoth, Micheal; Tugume, Lillian; Ssembambulidde, Kenneth; Musubire, Abdu K.; Bangdiwala, Ananta S.; Buzibye, Allan; Muzoora, Conrad; Svensson, Elin M.; Aarnoutse, Rob; Boulware, David R.; Elliott, Alison M.High-dose rifampicin may improve outcomes of tuberculous meningitis (TBM). Little safety or pharmacokinetic (PK) data exist on high-dose rifampicin in human immunodeficiency virus (HIV) coinfection, and no cerebrospinal fluid (CSF) PK data exist from Africa. We hypothesized that high-dose rifampicin would increase serum and CSF concentrations without excess toxicity. Methods. In this phase II open-label trial, Ugandan adults with suspected TBM were randomized to standard-of-care control (PO-10, rifampicin 10 mg/kg/day), intravenous rifampicin (IV-20, 20 mg/kg/day), or high-dose oral rifampicin (PO-35, 35 mg/kg/ day). We performed PK sampling on days 2 and 14. The primary outcomes were total exposure (AUC0–24), maximum concentration (Cmax), CSF concentration, and grade 3–5 adverse events. Results. We enrolled 61 adults, 92% were living with HIV, median CD4 count was 50 cells/μL (interquartile range [IQR] 46–56). On day 2, geometric mean plasma AUC0–24hr was 42.9·h mg/L with standard-of-care 10 mg/kg dosing, 249·h mg/L for IV-20 and 327·h mg/L for PO-35 (P < .001). In CSF, standard of care achieved undetectable rifampicin concentration in 56% of participants and geometric mean AUC0–24hr 0.27 mg/L, compared with 1.74 mg/L (95% confidence interval [CI] 1.2–2.5) for IV-20 and 2.17 mg/L (1.6–2.9) for PO-35 regimens (P < .001). Achieving CSF concentrations above rifampicin minimal inhibitory concentration (MIC) occurred in 11% (2/18) of standard-of-care, 93% (14/15) of IV-20, and 95% (18/19) of PO-35 participants. Higher serum and CSF levels were sustained at day 14. Adverse events did not differ by dose (P = .34). Conclusions. Current international guidelines result in sub-therapeutic CSF rifampicin concentration for 89% of Ugandan TBM patients. High-dose intravenous and oral rifampicin were safe and respectively resulted in exposures ~6- and ~8-fold higher than standard of care, and CSF levels above the MIC.Item Low Antituberculosis Drug Concentrations in HIV-Tuberculosis- Coinfected Adults with Low Body Weight: Is It Time To Update Dosing Guidelines?(Antimicrob Agents Chemother, 2019) Sekaggya-Wiltshire, Christine; Chirehwa, Maxwell; Musaazi, Joseph; Braun, Amrei von; Buzibye, Allan; Muller, Daniel; Gutteck, Ursula; Motta, Ilaria; Calcagno, Andrea; Fehr, Jan S.; Kambugu, Andrew; Castelnuovo, Barbara; Lamorde, Mohammed; Denti, PaoloAntituberculosis drugs display large pharmacokinetic variability, which may be influenced by several factors, including body size, genetic differences, and drug-drug interactions. We set out to determine these factors, quantify their effect, and determine the dose adjustments necessary for optimal drug concentrations. HIVinfected Ugandan adults with pulmonary tuberculosis treated according to international weight-based dosing guidelines underwent pharmacokinetic sampling (1, 2, and 4 h after drug intake) 2, 8, and 24 weeks after treatment initiation. Between May 2013 and November 2015, we enrolled 268 patients (148 males) with a median weight of 53.5 (interquartile range [IQR], 47.5 to 59.0) kg and a median age of 35 (IQR, 29 to 40) years. Population pharmacokinetic modeling was used to interpret the data and revealed that patients weighing 55 kg achieved lower concentrations than those in higher weight bands for all drugs in the regimen. The models predicted that this imbalance could be solved with a dose increment of one fixed-dose combination (FDC) tablet for the weight bands of 30 to 37 and 38 to 54 kg. Additionally, the concomitant use of efavirenz increased isoniazid clearance by 24.1%, while bioavailability and absorption of rifampin and isoniazid varied up to 30% in patients on different formulations. Current dosing guidelines lead to lower drug exposure in patients in the lower weight bands. Simply adding one FDC tablet to current weight band-based dosing would address these differences in exposure and possibly improve outcomes. Lower isoniazid exposures due to efavirenz deserve further attention, as does the quality of currently used drug formulations of anti-TB drugs. (This study has been registered at ClinicalTrials.gov under identifier NCT01782950.)Item Oral pre-exposure prophylaxis preference, uptake, adherence and continuation among adolescent girls and young women in Kampala, Uganda: a prospective cohort study(Journal of the International AIDS Society, 2022) Mayanja, Yunia; Kamacooko, Onesmus; Lunkuse, Jane Frances; Muturi-Kioi, Vincent; Buzibye, Allan; Omali, Denis; Chinyenze, Kundai; Kuteesa, Monica; Kaleebu, Pontiano; Price, Matt A.Oral pre-exposure prophylaxis (PrEP) has been scaled up; however, data from real-world settings are limited. We studied oral PrEP preference, uptake, adherence and continuation among adolescent girls and young women (AGYW) vulnerable to HIV in sub-Saharan Africa. Methods: We conducted a prospective cohort study among 14- to 24-year-old AGYW without HIV who were followed for 12 months in Kampala, Uganda. Within at least 14 days of enrolment, they received two education sessions, including demonstrations on five biomedical interventions that are; available (oral PrEP), will be available soon (long-acting injectable PrEP and anti-retroviral vaginal ring) and in development (PrEP implant and HIV vaccine). Information included mode and frequency of delivery, potential side effects and method availability. Volunteers ranked interventions, 1 = most preferred to 5 = least preferred. Oral PrEP was “preferred” if ranked among the top two choices. All were offered oral PrEP, and determinants of uptake assessed using Poisson regression with robust error variance. Adherence was assessed using plasma tenofovir levels and self-reports. Results: Between January and October 2019, 532 volunteers were screened; 285 enrolled of whom 265 received two education sessions. Mean age was 20 years (SD±2.2), 92.8% reported paid sex, 20.4% reported ≥10 sexual partners in the past 3 months, 38.5% used hormonal contraceptives, 26.9% had chlamydia, gonorrhoea and/or active syphilis. Of 265 volunteers, 47.6% preferred oral PrEP. Willingness to take PrEP was 90.2%; however, uptake was 30.6% (n = 81). Following enrolment, 51.9% started PrEP on day 14 (same day PrEP offered), 20.9% within 30 days and 27.2% after 30 days. PrEP uptake was associated with more sexual partners in the past 3 months: 2–9 partners (aRR = 2.36, 95% CI: 1.20–4.63) and ≥10 partners (aRR 4.70, 95% CI 2.41–9.17); oral PrEP preference (aRR 1.53, 95% CI 1.08–2.19) and being separated (aRR 1.55, 95% CI 1.04–2.33). Of 100 samples from 49 volunteers during follow up, 19 had quantifiable tenofovir levels (>10 μg/L) of which only three were protective (>40 μg/L). Conclusions: Half of AGYW preferred oral PrEP, uptake and adherence were low, uptake was associated with sexual behavioural risk and oral PrEP preference. Development of alternative biomedical products should be expedited to meet enduser preferences and, community delivery promoted during restricted movement.Item Prevalence of substandard quality artemetherlumefantrine antimalarial agents in Uganda(Research Square, 2022) Ocan, Moses; Nakalembe, Loyce; Otike, Caroline; Nambatya, Winnie; Omali, Denis; Buzibye, Allan; Nsobya, SamSubstandard antimalarial agents are a key challenge to effective malaria control and elimination efforts especially in sub-Saharan Africa. The quality of antimalarial agents in most low-andmiddle income countries (LMICs) is affected by several factors including inadequate regulation and limited resources. In this study, we assessed the pharmacopeial quality of Artemether-Lumefantrine (AL) in low and high malaria transmission settings in Uganda. Methods: This was a cross-sectional study conducted among randomly selected drug outlets (pharmacies/drug shops). The AL antimalarial agents available in drug outlets were purchased using overt method. The samples were screened for quality using visual inspection, weight uniformity and content assay tests. The assay test was done using Liquid chromatography-mass spectrometry (LC-MS) following International and Unites States Pharmacopoeia (USP) method. The samples were considered substandard if the Active Pharmaceutical Ingredient (API) content was outside 90-110% range of the label claim. Data was analysed using descriptive statistics and presented as means with standard deviations, frequencies, and proportions. Correlation between medicine quality and independent variables was determined using fisher’s exact test of independence at 95% level of significance. Results: A total of 74 AL antimalarial samples were purchased from high (49/74; 66.2%) and low (25/74; 33.8%) malaria transmission settings. The most common batch of AL was LONART, 32.4% (24/74), with 33.8% (25/74) having a ‘Green leaf logo’. Overall, prevalence of substandard quality artemetherlumefantrine was 18.9% (14/74; 95%CI: 11.4-29.7). Substandard quality AL was significantly associated with setting (p=0.002). A total of 10 samples (13.5%) failed artemether content assay while, 4 samples (5.4%, 4/74) had substandard lumefantrine content. One sample from a high malaria transmission setting failed both Artemether and Lumefantrine assay test. Of the samples that failed artemether assay test, majority, 90% had low (<90%) artemether content. Conclusion: Substandard quality AL, the recommended first-line antimalarial agent in treatment of uncomplicated malaria is common especially in high malaria transmission settings. There is need for regular surveillance and monitoring of the quality of artemisinin based antimalarial agents across the country.Item Relating CYP2B6 Genotype and EFV Resistance Among Women Living With HIV With High Viremia in Uganda: A Nested Cross-Sectional Study.(Research Square, 2021) Buzibye, Allan; Wools-Kaloustian, Kara; Olagunju, Adeniyi; Twinomuhwezi, Ellon; Yiannoutsos, Constantin; Owen, Andrew; Neary, Megan; Matovu, Joshua; Banturaki, Grace; Castelnuovo, Barbara; Lamorde, Mohammed; Khoo, Saye; Waitt, Catriona; Kiragga, AgnesWe investigated the association between CYP2B6 polymorphisms and efavirenz drug resistance among women living with HIV started on anti-retroviral therapy during pregnancy and with high viremia during post-partum. Methods This was a cross sectional study. Women between 6-12 weeks post-partum with viral load >1000 copies/ml were eligible. Sanger sequencing to detect resistant mutations and host genotyping were performed. We categorized efavirenz metabolizer genotype according to the AIDS clinical trials group algorithm as slow, intermediate and extensive; and compared efavirenz resistance among the metabolizer genotypes. Results Over a one-year period (July 2017-July 2018), three hundred and thirty two women were screened of whom 112 (34.8%) had viral load ≥1000 copies/ml of whom 62 had whole blood available for genotyping. Fifty-nine of these women had both viral resistance and human host genotypic results. We observed a higher frequency of efavirenz resistance among slow metabolizers (47% versus 34% in extensive and 28% in intermediate, metabolizers) but due to low numbers, this was not statistically significant. Conclusions Our findings raise the possibility that CYP2B6 polymorphism may contribute to efavirenz drug resistance in women started on antiretroviral therapy during pregnancy and with high viremia in the post-partum period. If confirmed in a larger study, this would have important implications for all patients in sub- Saharan Africa receiving efavirenz and add further support to the changes in World Health Organization policy to switch away from efavirenz as first line antiretroviral therapy in countries with a high prevalence of CYP2B6 polymorphisms.Item Therapeutic drug monitoring of nevirapine in saliva in Uganda using high performance liquid chromatography and a low cost thin-layer chromatography technique(BMC Infectious Diseases, 2014) Lamorde, Mohammed; Fillekes, Quirine; Sigaloff, Kim; Kityo, Cissy; Buzibye, Allan; Kayiwa, Joshua; Merry, Concepta; Nakatudde-Katumba, Lillian; Burger, David; Rinke de Wit, Tobias F.In resource limited settings access to laboratory monitoring of HIV treatment is limited and therapeutic drug monitoring is generally unavailable. This study aimed to evaluate nevirapine concentrations in saliva using low-cost thin-layer chromatography (TLC) and nevirapine concentrations in plasma and saliva using high performance liquid chromatography (HPLC) methods; and to correlate nevirapine plasma concentrations to HIV treatment outcomes in Ugandan patients. Methods: Paired plasma and stimulated saliva samples were obtained from Ugandan, HIV-infected adults on nevirapine-based ART. Nevirapine concentrations were measured using a validated HPLC method and a novel TLC method. Plasma nevirapine concentrations <3.0 mg/L using HPLC were considered subtherapeutic. Negative/positive predictive values of different thresholds for subtherapeutic nevirapine concentrations in saliva were determined. Virologic testing and, if applicable, HIV drug resistance testing was performed. Results: Median (interquartile range, IQR) age of 297 patients was 39.1 (32.8-45.2) years. Three hundred saliva and 287 plasma samples were available for analysis. Attempts failed to determine nevirapine saliva concentrations by TLC. Using HPLC, median (IQR) nevirapine concentrations in saliva and plasma were 3.40 (2.59-4.47) mg/L and 6.17 (4.79-7.96) mg/L, respectively. The mean (coefficient of variation,%) nevirapine saliva/plasma ratio was 0.58 (62%). A cut-off value of 1.60 mg/L nevirapine in saliva was associated with a negative/positive predictive value of 0.99/ 0.72 and a sensitivity/specificity of 87%/98% for predicting subtherapeutic nevirapine plasma concentrations, respectively. Only 5% (15/287) of patients had subtherapeutic nevirapine plasma concentrations, of which 3 patients had viral load results > 400 copies/mL. Patients with nevirapine concentrations in plasma <3.0 mg/L had an Odds Ratio of 3.29 (95% CI: 1.00 – 10.74) for virological failure (viral load >400 copies/mL). Conclusions: The low-cost TLC technique for monitoring nevirapine in saliva was unsuccessful but monitoring nevirapine saliva and plasma concentrations using HPLC was shown to be feasible in the research/specialist context in Uganda. Further optimization and validation is required for the low-cost TLC technique.Item Unintended Pregnancies Observed With Combined Use of the Levonorgestrel Contraceptive Implant and Efavirenz-based Antiretroviral Therapy: A Three-Arm Pharmacokinetic Evaluation Over 48 Weeks(Clinical Infectious Diseases, 2016) Scarsi, Kimberly K.; Darin, Kristin M.; Nakalema, Shadia; Back, David J.; Byakika-Kibwika, Pauline; Else, Laura J.; Penchala, Sujan Dilly; Buzibye, Allan; Cohn, Susan E.; Merry, Concepta; Lamorde, MohammedLevonorgestrel subdermal implants are preferred contraceptives with an expected failure rate of <1% over 5 years. We assessed the effect of efavirenz- or nevirapine-based antiretroviral therapy (ART) coadministration on levonorgestrel pharmacokinetics. Methods. This nonrandomized, parallel group, pharmacokinetic evaluation was conducted in three groups of human immunodeficiency virus–infected Ugandan women: ART-naive (n = 17), efavirenz-based ART (n = 20), and nevirapine-based ART (n = 20). Levonorgestrel implants were inserted at baseline in all women. Blood was collected at 1, 4, 12, 24, 36, and 48 weeks. The primary endpoint was week 24 levonorgestrel concentrations, compared between the ART-naive group and each ART group by geometric mean ratio (GMR) with 90% confidence interval (CI). Secondary endpoints included week 48 levonorgestrel concentrations and unintended pregnancies.