<p>Many studies have reported low cure rates for multidrug-resistant tuberculosis (MDRTB) patients and MDR-TB patients co-infected with human immunodeficiency virus (HIV). However, little is&nbsp / known about the effect of HIV infection and antiretroviral therapy on the treatment outcomes of MDR-TB in South Africa. Therefore, the objectives of the study are: to find out whether HIV infection&nbsp / and interactions between ARVs and second line anti-TB drugs have an impact on the following MDR-TB treatment outcomes: cure rate and treatment failure at Brewelskloof Hospital. MDR-TB&nbsp / patients were treated for 18-24 months. The study was designed as a case-control retrospective study comparing MDR-TB treatment outcomes between HIV positive (cases) and HIV negative&nbsp / patients (controls). Patients were included in the study only if they complied with the following criteria: sensitivity to second line anti-TB drugs, MDR-TB infection, co-infection with HIV (for some&nbsp / of them), male and female patients, completion of treatment between 1 January 2006 and 31 December 2008. Any patients that presented with extreme drug-resistant tuberculosis (XDR-TB)&nbsp / were excluded from the study. Data were retrospectively collected from each patient&rsquo / s medical records. There were a total of 336 patients of which 242 (72%) were MDR-TB patients and 94&nbsp / (27.9%) MDRTB co-infected with HIV patients. Out of the 242 MDR-TB patients, 167 (69.2%) were males and 75 (30.7%) were females. Of the 94 patients with MDR-TB co-infected with HIV, 51&nbsp / (54.2%) males and 43 (45.7%) females. Patients with multidrug-resistant tuberculosis co-infected with HIV who qualify for antiretroviral therapy were treated with stavudine, lamivudine and&nbsp / efavirenz while all MDR-TB patients were given kanamycin, ethionamide, ofloxacin, cycloserine and pyrazinamide. The cure rate of MDR-TB in HIV (+) patients and in HIV (-) patients is 34.5%&nbsp / and 30 % respectively. There is no significant difference between both artes (pvalue = 0.80). The MDR-TB cure rate in HIV (+) patients taking antiretroviral drugs and in HIV (+) patients without&nbsp / antiretroviral therapy is 35% and 33% respectively. The difference between both rates is not statistically significant. The study shows that 65 (28.0%) patients completed MDR-TB treatment but&nbsp / could not be classified as cured or failure, 29 (12.5%) patients failed, 76 (32.7%) defaulted, 18 (7.7%) were transferred out and 44 (18.9%) died. As far as treatment completed and defaulted is concerned,&nbsp / there is no significant statistical difference between HIV (+) and HIV (-) The number of patients who failed the MDR-TB treatment and who were transferred out is significantly higher in the HIV (-)&nbsp / group than in the HIV (+) group. Finally the number of MDR-TB patients who died is significantly higher in the HIV (+) group). The median (range) duration of antiretroviral therapy before starting&nbsp / anti-tuberculosis drugs is 10.5 (1-60) months. According to this study results, the MDR-TB treatment cure rate at Brewelkloof hospital is similar to the cure rate at the national level. The study also&nbsp / hows that HIV infection and antiretroviral drugs do not influence any influence on MDR-TB treatment outcomes.</p>

Longitudinal data tend to be correlated and hence posing a challenge in the analysis since the correlation has to be accounted for to obtain valid inference. We study various statistical methods for such correlated longitudinal binary responses. These models can be grouped into five model families, namely, marginal, subject-specific, transition, joint and semi-parametric models. Each one of the models has its own strengths and weaknesses. Application of these models is carried out by analyzing data on patient’s adherence status to highly active antiretroviral therapy (HAART). One other complicating issue with the HAART adherence data is missingness. Although some of the models are flexible in handling missing data, they make certain assumptions about missing data mechanisms, the most restrictive being missing completely at random (MCAR). The test for MCAR revealed that dropout did not depend on the previous outcome. A logistic regression model was used to identify predictors for the patients’ first month’s adherence status. A marginal model was then fitted using generalized estimating equations (GEE) to identify predictors of long-term HAART adherence. This provided marginal population-based estimates, which are important for public health perspective. We further explored the subject’s specific effects that are unique to a particular individual by fitting a generalized linear mixed model (GLMM). The GLMM was also used to assess the association structure of the data. To assess whether the current optimal adherence status of a patient depended on the previous adherence measurements (history) in addition to the explanatory variables, a transition model was fitted. Moreover, a joint modeling approach was used to investigate the joint effect of the predictor variables on both HAART adherence status of patients and duration between successive visits. Assessing the association between the two outcomes was also of interest. Furthermore, longitudinal trajectories of observed data may be very complex especially when dealing with practical applications and as such, parametric statistical models may not be flexible enough to capture the main features of the longitudinal profiles, and so a semiparametric approach was adopted. Specifically, generalized additive mixed models were used to model the effect of time as well as interactions associated with time non-parametrically. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Background: Multiple factors contribute to mother-to-child transmission (MTCT) of HIV-1, including virological, obstetric and biological factors. Other possible contributory determinants for high MTCT rates include immunological factors such as host genetics and viral genetic variations. Despite several therapeutic, prophylactic and obstetric interventions to reduce the proportion of infants infected during labour and delivery, mechanisms for intrapartum HIV-1 transmission remain elusive and current interventions, could, therefore remain sub-optimal. Much controversy has surrounded the correlation of HIV-1 RNA (viral load) in the systemic and genital compartments of women. The influence of short-term antiretroviral (ARV) drugs on genital tract HIV-1 is also unclear. At the time the present study was initiated, a regimen of maternal intrapartum and neonatal postpartum single-dose Nevirapine (sdNVP) was the standard of care for the prevention of mother-to-child transmission (PMTCT). In most low and middle-income countries, including South Africa, sdNVP has been documented as effective intrapartum HIV-1 prevention based on plasma pharmacokinetic levels, decreased viral loads (HIV-1 RNA) and reduced rates of intrapartum transmission, yet operational studies continue to report high intrapartum transmission rates despite the administration of sdNVP. As a result perinatal HIV-1 transmission remains a significant public health concern in several African countries. Aim: The primary aim of this study was to describe the pharmacological dynamics of Nevirapine in association with virological and immunological risk factors for intrapartum HIV-1 transmission in a South African PMTCT programme where sdNVP was the standard of care. Methods: Following regulatory approval from the Biomedical Research Ethics Committee at the University of KwaZulu-Natal (UKZN), one hundred and twenty pregnant HIV-infected women who received the sdNVP regimen for prevention of mother-to-child HIV-1 transmission were enrolled between April-December 2006 at King Edward VIII Hospital (KEH) in Durban. Blood and cervicovaginal lavage (CVL) samples were collected from women at pre-NVP (during pregnancy) and post-NVP dosing (during labour/delivery). In addition to infant blood sampling at birth (post-NVP), postnatal infants were assessed at four and six weeks postnatally. Pharmacological laboratory investigations involved measurement of NVP drug concentration by Tandem Mass spectrophotometry. Virological investigations comprised HIV-1 RNA (viral load) quantitation, HIV-1 drug resistance testing (HIV-1 transmitting women only) and HIV-1 DNA PCR testing (infants only). Immunological investigations were only undertaken in a selected case-control subset of HIV-1 transmitting women and their infants. In this component, laboratory investigations included the determination of CCL3 and CCL3-L1 gene copy numbers, identification of single nucleotide polymorphisms (SNP’s) and haplotype characterisation of the CCL3 gene. All women were also screened for the presence of sexually transmitted infections (STI’s) during pregnancy. Results: One hundred and twenty women were enrolled onto this study. Of these, 110 women delivered 117 live infants (103 singletons and 7 twin pairs). Twelve (10.9%) women transmitted HIV-1 to their infants, while 95 (86.0%) were classified as non-transmitters. As a result of seven twin deliveries, the infant cohort comprised of 117 infants in total. Following two separate DNA PCR tests, HIV-1 infection was identified in 14 (11.9%) of study infants while the remaining 90 (76.9%) were exposed-uninfected. HIV infection status remained unknown for 13 infants due to infant demise (1.7%), lost to follow-up (7.7%) or study withdrawal (1.7%). During active labour (sampling that was best representative of the intrapartum phase) and within 20 hours of dosing, the median NVP concentration of 1070 ng/ml in the maternal systemic compartment was almost 44 times higher than the NVP levels detected in the genital compartment [24.5 ng/ml] (p < 0.001). NVP drug levels were below the 100 ng/ml therapeutic target in seven (13.7%) of 51 plasma and in all 39 CVL samples. While no significant association was found between NVP concentration in the systemic compartment and HIV-1 transmission (p = 0.4), this association was statistically significant in the genital compartment(p = 0.02). The median plasma NVP level detected among infants at birth was 83 times above the IC50 WT (10 ng/ml) and eight times higher than the 100 ng/ml therapeutic target for NVP. More than 71.0% of the infants achieved NVP drug levels above the therapeutic target. In general, higher levels of HIV-1 RNA (viral load) were observed in maternal plasma when compared to CVL. Following intrapartum sdNVP dosing, reduction in HIV-1 RNA levels did occur, however R80.0% of the women experienced no change to their HIV-1 RNA levels in both systemic and genital compartments during active labour. These findings were further supported by the strong correlation observed when comparing pre and post-NVP HIV-1 RNA levels in both maternal systemic [r = 0.81, p < 0.0001] and genital compartments [r = 0.80, p < 0.0001] during active labour. HIV-1 transmitting women had significantly higher viral loads than their non-transmitting counterparts in systemic and genital compartments, before and after intrapartum sdNVP administration. In terms of perinatal transmission this observation was only statistically significant for plasma (p = 0.02) and not CVL (p = 0.7). Maternal viral load was inversely correlated with maternal CD4 cell counts in both systemic and genital compartments. Almost 40.0% of women in this study had at least one type of STI detected during pregnancy. Maternal STI’s were detected in four (66.6%) intrapartum transmitting women and in 38 (38.8%) of non-transmitting women. No significant association was observed between the presence of maternal STI’s and the risk for intrapartum MTCT (p = 0.2,RR: 2.90, 95% CI: 0.60-15.40). The presence of maternal STI’s was associated with higher median viral loads in both systemic and genital compartments of all women, independent of intrapartum HIV-1 transmission. Despite trial-like conditions and optimal sdNVP dosing, the overall MTCT rate in this exclusively formula-fed cohort was 11.9%, of which 50.0% were in utero and 50.0% were intrapartum HIV-1 transmissions. In utero and intrapartum MTCT rates were 5.9% and 5.9% respectively. Discussion/Conclusion: Detectable CVL HIV-1 RNA that correlated well with plasma HIV-1 RNA, in conjunction with sub-optimal NVP drug concentration in maternal CVL during active labour, suggests that intrapartum HIV-1 infected women continue to act as reservoirs for both vertical and horizontal HIV-1 transmission throughout the duration of pregnancy. These findings confirm that the role of sdNVP in PMTCT was primarily one of infant prophylaxis. This was further supported by relatively unchanged maternal HIV-1 RNA (viral load) during active labour, in both systemic and genital compartments. Early identification of women who need highly active antiretroviral therapy (HAART), and initiation of such therapy as early as possible during pregnancy, not only benefits maternal health but remains the best prophylaxis against mother-to-child HIV-1 transmission. Universal access to HAART and improving strategies to optimize coverage of the current dual ARV regimen sdNVP and Zidovudine for PMTCT remain urgent research priorities in several resource-limited settings. Ongoing STI counseling, intensive screening/testing of women and their partners together promotion of condom usage, safer sex practices and aggressive STI treatment are simple interventions with tremendous impact for PMTCT in resource-limited settings. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2009.

Highly active antiretroviral therapy (HAART) is currently the only treatment that effectively reduces the morbidity and mortality of individuals infected with Human Immunodeficiency Virus-1 (HIV-1). Standard HAART regimens typically comprise 2 nucleoside reverse transcriptase inhibitors and either one non-nucleoside reverse transcriptase inhibitor or a protease inhibitor. These drugs bind to and inhibit the HIV-1 Reverse Transcriptase and Protease enzymes respectively, thereby suppressing viral replication. The nucleoside reverse transcriptase inhibitors promote mitochondrial (mt) dysfunction by strongly inhibiting mt polymerase gamma (Pol-y) and subsequently, mtDNA replication. In contrast, the non-nucleoside reverse transcriptase inhibitors, efavirenz (EFV) and nevirapine (NVP) do not inhibit Pol-y although EFV has been shown to induce mt depolarisation ( mlow) in vitro at supra-therapeutic concentrations. However, the capacity of non-nucleoside reverse transcriptase inhibitor drugs to induce mt toxicity in vivo previously remained undetermined. The objective of this study was to determine the influence of EFV and NVP on peripheral lymphocyte mt transmembrane potential (Avj/m) and apoptosis in HIV-1-infected patients treated with these non-nucleoside reverse transcriptase inhibitors. Thirty-two HIV-1-infected patients on HAART between 4 and 24 months (12 on EFV, 20 on NVP) and 16 HAART-naive HIV-1-infected patients were enrolled into this study. All participants were black South African patients. Spontaneous peripheral lymphocyte apoptosis and mlow were measured ex vivo by flow cytometry for all patients. CD4 T-helper apoptosis for the EFV and NVP cohorts was 19.38% ± 2.62% and 23.35% ± 1.51% (mean ± SEM), respectively, whereas total lymphocyte mlow was 27.25% ± 5.05% and 17.04% ± 2.98%, respectively. Both parameters for each cohort were significantly lower (P < 0.05) than that of the HAART-naive patients. The NVP cohort exhibited both a significant time dependent increase in peripheral lymphocyte ö¿mlow (P = 0.038) and correlation between Thelper apoptosis and low (P = 0.0005). These trends were not observed in the EFV cohort. This study provides evidence that both EFV and NVP induce peripheral lymphocyte ö¿ m low in HIV-1-infected patients on non-nucleoside reverse transcriptase inhibitor-based HAART, which in the case of NVP is sufficient to induce the apoptosis cascade. / Thesis (M.Med.Sci.)--University of KwaZulu-Natal, 2008.

In South Africa 1 000 people die of AIDS everyday and 100 000 more people require ARVs every year. There is therefore an urgent need to provide access to ARVs andother essential medicines. The South African Constitution requires the government totake reasonable measures to ensure access to health care. The government has cited financial constraints as the major ohstacle to fulfilling this constitutional imperative. In an effort to stretch their budgetary resource other medium-income countries have used measures such as compulsory licences, voluntary licences and parallel importation. These measures, provided for in the TRIPS Agreement and the Doha Declaration, are available under South African legislation but have not been properly implemented due to a lack of political will. The proper use of compulsory licences by the South African government is vital because all twelve of the ARVs on the World Health Organisation's Essential Medicines List are protected in South Africa by our patent laws. However, in order to issue compulsory licences more easily and quickly the South African Legislature will need to pass legislation which clarifies the ambiguities contained in TRIPS and the Doha Declaration. Other methods to lower the price of medicines include the segmentation of the South African market in order to facilitate differential pricing. The State must balance its use of such measures with programmes to incentivise research and development into neglected diseases and HIV/AIDS. Such programmes will also assist the State's capacity to conduct its own research and development into new medicines, whilst bolstering its domestic pharmaceutical manufacturing capacity. The ultimate solution to South Africa's access to medicine problem is to create a pharmaceutical manufacturing industry capable of producing the most complex medicines, so as to lessen its dependence on drug manufacturers reducing their prices. The way to create a sophisticated pharmaceutical manufacturing capacity is to use the flexibilities in TRIPS and to uphold South Africa's high patent standards. The Constitutional Court's involvement is essential in order to force the State to implement its own policies so as to provide access to affordable medicines. / Thesis (LL.M.)-University of KwaZulu-Natal, Durban, 2008.

RN/AIDS has had a particularly devastating effect on sub-Saharan nations, including South Africa. Thus, a national rollout of antiretroviral drugs - capable of mitigating the effects of the epidemic - has been vigorously demanded by the South African public. Eventually bowing to public pressure, the Government began to implement the rollout of the drugs at public health facilities in early 2004. The University of KwaZulu-Natal announced in 2004 that it too would provide access to antiretroviral drugs for all students who require them. Thus, there is an urgent need for the institution to develop promotional campaigns that not only promote the service but that also deal with the fall-out from the problematic national rollout, and that address the complicated nature of antiretroviral therapy. The focus of this dissertation is on a promotional needs analysis for the antiretroviral rollout at the University. Specifically, the primary research aimed to determine the knowledge, attitudes and beliefs of the general student population on the topic of antiretrovirals, and by doing so, identify the needs of this audience that will have to be addressed by future promotional campaigns. The theoretical framework used to inform the research design and questions is that of social marketing; a relatively new approach to social change that uses principles of commercial marketing to achieve results among target audiences. The results of the research suggest that future promotional messages and campaigns directed at the general student population will need to focus on the following issues: clarifying the distinctions between different contexts of ARV use; increasing the awareness of the rollout at UKZN as a prerequisite to stimulating demand; addressing negative beliefs and misconceptions regarding ARVs; emphasising complementary practices to be used by individuals with RN/AIDS; addressing issues of stigma and discrimination and encouraging students to act as sources of support and information for other students. In the case of certain messages, segmentation - on the basis of race and campus - may result in a more effective dissemination of information to the target audiences. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, 2005.

This dissertation has been motivated by the prolonged deficiency of access to advanced regimens of Antiretroviral drugs(ARVs) and efficient health services by people living with HIV/AIDS (PLWHA) in Zambia, a least developed Member of the World Trade Organisation (WTO). Zambia‘s reality of dire provision of health services particularly essential medicines persists despite the urgent need for sustainable access to ARV drugs in poor African countries worst affected by HIV/AIDS, having been accentuated in the international declaration on Trade Related Aspects on Intellectual Property Rights (TRIPS) and Public Health. Furthermore, under international human rights law of treaties, access to medicines including ARV drugs, has been recognised as a core component of the right to health and or life which needs to be progressively realised by governments, even in the advent of globalisation of domestic health services including provision of medicines. Whilst the Zambian government has highlighted lack of funds as the foremost impediment to efficient supply of health services particularly essential medicines. Conversely the WTO has pronounced lack of legal adoption of a plethora of flexibilities envisaged in its relevant international agreements by most poor Members, as the foremost impediment to fostering efficient public health service delivery including access to ARV drugs and therapy for PLWHA. Thus to assist in ascertaining whether the issue of deficient access to ARV drugs as a health service is as a result of legal unpreparedness in poor countries specifically Zambia; or whether it is due to provisions in the WTO trade agreements that foster globalisation of health services through liberalised trade in services and pharmaceutical patent protection of essential drugs. This dissertation will analyse the WTO‘s multilateral trade agreements and their legal impact on access to ARV drugs as a health service and a human right to health in Zambia. The foregoing analysis will be conducted through a desk review of literature on the subject, making use of paper and electronic sources. / Thesis (LL.M.)-University of KwaZulu-Natal, Durban, 2012.

Introduction APOBEC3G and other related cellular cytosine deaminase family members have potent antiviral activity. In the absence of HIV-1 Vif, APOBEC3G mutates the viral DNA during viral reverse transcription. Our knowledge of the Vif-APOBEC3G interaction in human populations infected with subtype C HIV-1 is limited. Investigation of interactions between HIV and its host is crucial as it can ultimately be exploited in vaccine and therapy design. We hypothesised that certain APOBEC3G haplotypes and/or their expression in peripheral blood mononuclear cells of seroconverters affect viral setpoint and CD4+ T cell counts. We also hypothesised that certain APOBEC3G genetic variants are associated with increased frequency of G to A hypermutations during primary HIV-1 infection and that Vif variability influences disease progression and its ability to neutralise APOBEC3G haplotypes. Methods Our South African study cohort consisted of females at high risk for HIV-1 infection and women with known recent HIV-1 infection. We used quantitative real-time PCR to measure APOBEC3G expression in HIV- and HIV+ samples during primary infection. APOBEC3G variants were identified by DNA sequencing and TaqMan Genotyping. The HIV-1env gene was sequenced to assess Env diversity and the extent of APOBEC3G induced hypermutations. Vif variability was assessed by plasma derived clonal Vif sequences (n= 10-20 per patient) and Vif function was assessed by APOBEC3G degradation assays and HIV-1 infectivity assays. Results We found no correlation between APOBEC3G expression levels and plasma viral loads (r=0.053, p=0.596) or CD4+ T cell counts (r=0.030, p=0.762) in 32 seroconverters. However, APOBEC3G expression levels were significantly higher in HIV- individuals compared to HIV+ individuals (p<0.0001) including matched pre- and post-infection samples from the same individuals (n=13, p<0.0001). Twenty five single nucleotide polymorphisms (SNPs) were identified within the APOBEC3G region. SNP 186R/R was associated with significantly higher viral loads (p=0.0097) and decreased CD4+ T cell levels (p=0.0081), indicating that 186R/R has a negative effect on HIV restriction. Overall HIV-1 env sequences contained a higher number of APOBEC3F compared to APOBEC3G-induced hypermutations and the number of APOBEC3F-induced hypermutations correlated negatively with viral load (r= -0.6, p=0.006) and positively with CD4 T cell counts (r=0.6, p=0.004). We cloned and sequenced a total of 392 subtype C Vifs, which showed an interpatient diversity of 6.2% to 19.2% at the amino acid level. Interestingly, Vif sequence comparison showed a strong preference for a Lysine or a Serine at position 36 for APOBEC3G 186R/R and APOBEC3G 186H/H individuals, respectively. Selected natural subtype C Vif alleles had greater ability to counteract wild type APOBEC3G 186H as compared to the APOBEC3G 186R variant as shown by both functional and HIV infectivity assays. Conclusions In conclusion, APOBEC3G expression in peripheral blood mononuclear cells does not correlate with viral loads or CD4+ T cell counts during primary HIV-1 subtype C infection. However, genetic variants of APOBEC3G may affect HIV-1 pathogenesis. Amino acid changes in Vif may influence its anti-APOBEC3 activity. HIV-1 subtype C Vifs may have adapted to counteract the more active wild type APOBEC3G as compared to the less active APOBEC3G 186R variant. These studies have improved our understanding of viral-host interactions in African populations and HIV-1 subtype C infections. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2014.

The relationships between post-traumatic growth (PTG), benefit finding, happiness, pessimism and antiretroviral (ART) medication adherence were examined among 10 people living with HIV or AIDS who attended HIV support groups, and were currently prescribed ART medications. Analyses indicated that none of these psychosocial factors were significantly correlated with ART adherence, that the relationships continued to be non-significant after pessimism was partialled out of the analysis, and that participants who reported achieving optimal ART adherence did not significantly differ from participants who reported taking less than optimal ART adherence in regards to PTG, benefit finding, subjective happiness, or pessimism. The results suggest that interventions designed to change these psychosocial factors may not be effective means of improving ART adherence. / Department of Psychological Science

The management of HIV-associated tuberculosis (TB) is complicated by the pharmacokinetic interactions between rifampicin (RMP) and co-administered protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors. Rifabutin (RBT) is an alternative rifamycin, preferred in patients requiring PIs. Recent studies suggest the current recommended dose of RBT in combination with boosted lopinavir (LPV/r) is suboptimal and there are insufficient pharmacokinetic data evaluating the interaction between RBT coadministered with efavirenz (EFV) and nevirapine (NVP). Pharmacogenomic studies have shown that RMP concentrations are lower in patients from sub-Saharan Africa with polymorphisms of the SLCO1B1gene but there is currently no data on the pharmacogenetic determinants of RBT exposure. The pharmacokinetics of RBT were evaluated at two different doses in HIV co-infected patients before and after the introduction of LPV/r, EFV and NVPbased antiretroviral therapy (ART). After six weeks of standard TB therapy, RBT 300 mg daily was started for four weeks. Thereafter patients were randomized to receive either RBT 150 mg daily or RBT 150 mg three times a week (TPW) with LPV/r, RBT 300mg or 450mg with NVP or RBT- 450mg or 600mg with efavirenz. After four weeks on the first RBT dose, patients switched to the alternate dose and continued until the end of TB treatment. Serial RBT and 25-O-desacetylrifabutin (dRBT) concentrations were measured during a dose interval before patients switched RBT doses. The median AUC0-24 and Cmax, of RBT in patients taking 150mg RBT TPW was significantly reduced when compared to the other treatment arms. 86% of patients whilst on this intermittent RBT arm had an AUC0-24 < 4.5 μg.h/mL, level that has been associated with acquired rifamycin resistance. Rifabutin exposure was maintained within the range of AUCs that have been shown to prevent acquired rifamycin resistance (ARR) with 150mg daily dosing in combination with LPV/r. In addition, the combination of RBT with NVP 300mg resulted in significantly increased exposure of RBT, with significantly higher exposure observed with 600mg RBT. However, the combination of RBT 450mg with EFV resulted in RBT exposure lower than 300mg RBT given alone in the same patients, whereas RBT 600mg plus NVP results in bioavailability of RBT equivalent to 300mg given alone. Rifabutin was well tolerated at all doses. Only three grade 4 laboratory toxicities, elevated transaminases, neutropenia, and uveitis, possibly related to RBT were reported in patients taking NVP. SLCO1B1 rs4149032 C>T polymorphism occurs frequently in African patients in Durban and may be associated with low RBT bioavailability. These findings support recommendations for the higher dose of RBT in combination with LPV and EFV but not with NVP. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.