Prevalence and predictors for cisplatin-induced toxicities in Zimbabwean women with cervical cancer.

Aim: To describe treatment-induced toxicities (TITs) and associated factors in Zimbabwean cancer patients receiving cisplatin. Methods: In total, 252 Zimbabwean women with cervical cancer, receiving cisplatin were followed up over 12 months for TITs and disease status. Results: Peripheral neuropathy (70%) and ototoxicity (53%) were most prevalent. Advanced disease (OR = 1.3; 95% CI = 1.1-1.5; p = 0.02), pain comedications (OR = 1.3; 95% CI = 1.1-1.5; p = 0.03), alcohol (OR = 2.8; 95% CI = 1.1-7.5; p = 0.04) and comorbidities (OR = 1.2; 95% CI = 1.1-1.4; p = 0.04) increased peripheral neuropathy and ototoxicity risk. Older age increased risk of disease progression (OR = 1.9; 95% CI = 1.4-3.0; p = 0.033). Conclusion: High peripheral neuropathy and ototoxicity prevalence were observed, which are not routinely monitored in Zimbabwe. There is a need for capacity building to incorporate comprehensive TIT testing and optimize cancer care in Zimbabwe.

Cancer treatment has side effects, also known as treatment-induced toxicities (TITs), that can lead to death if not management properly. African populations are more likely to develop TITs, however, not many studies research on TITs in Africans and why they are more prone to TITs. This study followed up 252 Zimbabwean women with cervical cancer, over 12 months for TITs and found that loss of sensation and ear complications most commonly occurred after treatment. Advanced disease, prescribed pain medication, alcohol consumption history and underlying diseases such as diabetes increased likelihood of TITs, while older age increased risk of unresponsive cancer. This study highlights a need to incorporate comprehensive monitoring for TITs for at-risk individuals toward improving cancer care.

A cervical cancer biorepository for pharmacogenomics research in Zimbabwe.

BACKGROUND: Research infrastructures such as biorepositories are essential to facilitate genomics and its growing applications in health research and translational medicine in Africa. Using a cervical cancer cohort, this study describes the establishment of a biorepository consisting of biospecimens and matched phenotype data for use in genomic association analysis and pharmacogenomics research. METHOD: Women aged > 18 years with a recent histologically confirmed cervical cancer diagnosis were recruited. A workflow pipeline was developed to collect, store, and analyse biospecimens comprising donor recruitment and informed consent, followed by data and biospecimen collection, nucleic acid extraction, storage of genomic DNA, genetic characterization, data integration, data analysis and data interpretation. The biospecimen and data storage infrastructure included shared -20 °C to -80 °C freezers, lockable cupboards, secured access-controlled laptop, password protected online data storage on OneDrive software. The biospecimen or data storage, transfer and sharing were compliant with the local and international biospecimen and data protection laws and policies, to ensure donor privacy, trust, and benefits for the wider community. RESULTS: This initial establishment of the biorepository recruited 410 women with cervical cancer. The mean (± SD) age of the donors was 52 (± 12) years, comprising stage I (15%), stage II (44%), stage III (47%) and stage IV (6%) disease. The biorepository includes whole blood and corresponding genomic DNA from 311 (75.9%) donors, and tumour biospecimens and corresponding tumour DNA from 258 (62.9%) donors. Datasets included information on sociodemographic characteristics, lifestyle, family history, clinical information, and HPV genotype. Treatment response was followed up for 12 months, namely, treatment-induced toxicities, survival vs. mortality, and disease status, that is disease-free survival, progression or relapse, 12 months after therapy commencement. CONCLUSION: The current work highlights a framework for developing a cancer genomics cohort-based biorepository on a limited budget. Such a resource plays a central role in advancing genomics research towards the implementation of personalised management of cancer.

Clinical and demographic characteristics of cervical cancer patients presenting at Parirenyatwa Hospital, Zimbabwe.

Cervical cancer is the leading cause of cancer deaths in women in Africa, predominately due to late diagnosis. This study aims to identify risk factors, potential prognostic indicators, and optimal treatment modalities for Zimbabwean cervical cancer patients. Medical records for 1063 cervical cancer patients were reviewed for sociodemographic, clinical, treatment, and response data. All data were analysed using SPSS version 25. More than half of the cohort was pre-menopausal (63%) with low (2%) history of cervical cancer screening. Schistosoma ova were observed in 2.4% of the tumour specimens. More than 50% were diagnosed at stage 3 and later, with a high frequency of comorbidities (~68%). This study highlights a need for improving screening education and uptake in Zimbabwe. Moreover, the current data provides a dataset for understanding cervical cancer pathogenesis and treatment responses in an African cohort.

The effect of ketoconazole on praziquantel pharmacokinetics and the role of CYP3A4 in the formation of X-OH-praziquantel and not 4-OH-praziquantel.

AIM: The study sought to determine the effect of ketoconazole (KTZ) on the pharmacokinetics of praziquantel (PZQ) and on the formation of its major hydroxylated metabolites, cis- and trans-4-OH-PZQ, and X-OH-PZQ in healthy subjects. METHODS: Two treatments were evaluated by single-dose PK studies; the reference treatment was a 20 mg/kg dose of praziquantel given alone. The test treatment was a 20 mg/kg dose of praziquantel given in combination with 200 mg of ketoconazole. The study had a balanced and randomised cross-over design. Serial blood samples were collected between 0 and 12 h after each drug administration. PZQ, and cis- and trans-4-OH-PZQ and X-OH-PZQ concentrations in plasma were determined by LC-MS. A non-compartmental approach was used for pharmacokinetic analysis. Data were analysed using ANOVA and assessment of the 90% confidence interval of the geometric means of the log-transformed PK parameters obtained for each treatment. RESULTS: The pharmacokinetics of PZQ following the two treatments, PZQ alone and PZQ + KTZ, were not equivalent based on the assessment of the 90% CI of the geometric mean ratios of the AUC and Cmax (α = 0.05). The geometric mean ratios of the AUC and Cmax were found to be 176.8% and 227% respectively. The 90% CI of the AUC and Cmax were found to be 129.8%-239.8% and 151.4%-341.4% respectively. The AUC of PZQ was increased by 75% with KTZ co-administration (3516 vs 6172 ng h/ml) (p < 0.01). Meanwhile, the mean AUC of trans-4-OH-PZQ increased by 67% (61,749 ng h/ml vs 103,105 ng h/ml) (p < 0.01). X-OH-PZQ levels were reduced by about 57% (semi-quantified as 7311 ng h/ml vs 3109 ng h/ml by using trans-4-OH as standards) (p < 0.01) with KTZ co-administration. CONCLUSIONS: The relative bioavailability of praziquantel was increased by concomitant KTZ administration. KTZ preferentially inhibited the formation of X-OH-PZQ rather than 4-OH-PZQ, confirming in vitro data which implicates CYP3A4 in the formation of X-OH-PZQ rather than 4-OH-PZQ. The 4-hydroxylation of PZQ was shown to be the major metabolic pathway of PZQ, as evidenced by larger quantities of 4-OH-PZQ produced, thus explaining the modest albeit significant effect of ketoconazole on PZQ pharmacokinetics.

Effect of Moringa oleifera Lam. leaf powder on the pharmacokinetics of nevirapine in HIV-infected adults: a one sequence cross-over study.

BACKGROUND: Moringa oleifera Lam., an herb commonly consumed by HIV-infected people on antiretroviral therapy, inhibits cytochrome P450 3A4, 1A2 and 2D6 activity in vitro; and may alter the pharmacokinetics (PK) of antiretroviral drugs metabolized via the same pathways. However, in vitro drug interaction activity may not translate to a clinically significant effect. Therefore, the effect of moringa leaf powder on the PK of nevirapine in HIV-infected people was investigated. METHODS: Adult patients at steady-state dosing with nevirapine were admitted for 12-h intensive PK sampling following a 21-day herbal medicine washout. Blood sampling was repeated after 14 days of nevirapine and moringa (1.85 g leaf powder/day) co-administration. Nevirapine plasma concentrations were determined by liquid chromatography-tandem mass spectrometry. To assess the effect of moringa on nevirapine PK, the change in nevirapine area under the plasma concentration-time curve (AUC) was determined. The mean difference in pre- and post-moringa nevirapine, maximum concentration (Cmax) and concentration at 12 h (C12h) were also calculated. The PK parameters were compared by assessing the post/pre geometric mean ratios (GMRs) and associated 90% confidence intervals (CIs). RESULTS: Pharmacokinetics analyses were performed on the results from 11 participants for whom complete data were obtained. The post/pre GMRs and associated 90% CIs for nevirapine were 1.07 (1.00-1.14) for the AUC; 1.06 (0.98-1.16) for Cmax and 1.03 (0.92-1.16) for C12h. CONCLUSION: Co-administration of Moringa oleifera Lam. leaf powder at the traditional dose did not significantly alter the steady-state PK of nevirapine. Trial registration number NCT01410058 (ClinicalTrials.gov).

Pharmacokinetics of Tamoxifen and Its Major Metabolites and the Effect of the African Ancestry Specific CYP2D6*17 Variant on the Formation of the Active Metabolite, Endoxifen.

Tamoxifen (TAM) is widely used in the treatment of hormone receptor-positive breast cancer. TAM is metabolized into the active secondary metabolite endoxifen (ENDO), primarily by CYP2D6. We aimed to investigate the effects of an African-specific CYP2D6 variant allele, CYP2D6*17, on the pharmacokinetics (PK) of TAM and its active metabolites in 42 healthy black Zimbabweans. Subjects were grouped based on CYP2D6 genotypes as CYP2D6*1/*1 or *1/*2 or *2/*2 (CYP2D6*1 or *2), CYP2D6*1/*17 or 2*/*17, and CYP2D6*17/*17. PK parameters for TAM and three metabolites were determined. The pharmacokinetics of ENDO showed statistically significant differences among the three groups. The mean ENDO AUC0-∞ in CYP2D6*17/*17 subjects was 452.01 (196.94) h·*ng/mL, and the AUC0-∞ in CYP2D6*1/*17 subjects was 889.74 h·ng/mL, which was 5-fold and 2.8-fold lower than in CYP2D6*1 or *2 subjects, respectively. Individuals who were heterozygous or homozygous for CYP2D6*17 alleles showed a 2- and 5-fold decrease in Cmax, respectively, compared to the CYP2D6*1 or *2 genotype. CYP2D6*17 gene carriers have significantly lower ENDO exposure levels than CYP2D6*1 or *2 gene carriers. Pharmacokinetic parameters of TAM and the two primary metabolites, N-desmethyl tamoxifen (NDT) and 4-hydroxy tamoxifen (4OHT), did not show any significant difference in the three genotype groups. The African-specific CYP2D6*17 variant had effects on ENDO exposure levels that could potentially have clinical implications for patients homozygous for this variant.

Warfarin Pharmacogenomics for Precision Medicine in Real-Life Clinical Practice in Southern Africa: Harnessing 73 Variants in 29 Pharmacogenes.

Pharmacogenomics is universally relevant for worldwide modern therapeutics and yet needs further development in resource-limited countries. While there is an abundance of genetic association studies in controlled medical settings, there is a paucity of studies with a naturalistic design in real-life clinical practice in patients with comorbidities and under multiple drug treatment regimens. African patients are often burdened with communicable and noncommunicable comorbidities, yet the application of pharmacogenomics in African clinical settings remains limited. Using warfarin as a model, this study aims at minimizing gaps in precision/personalized medicine research in African clinical practice. We present, therefore, pharmacogenomic profiles of a cohort of 503 black Africans (n = 252) and Mixed Ancestry (n = 251) patients from Southern Africa, on warfarin and co-prescribed drugs in a naturalized noncontrolled environment. Seventy-three (n = 73) single nucleotide polymorphisms (SNPs) in 29 pharmacogenes were characterized using a combination of allelic discrimination, Sanger sequencing, restriction fragment length polymorphism, and Sequenom Mass Array. The common comorbidities were hypertension (43-46%), heart failure (39-45%), diabetes mellitus (18%), arrhythmia (25%), and HIV infection (15%). Accordingly, the most common co-prescribed drugs were antihypertensives, antiarrhythmic drugs, antidiabetics, and antiretroviral therapy. We observed marked variation in major pharmacogenes both at interethnic levels and within African subpopulations. The Mixed Ancestry group presented a profile of genetic variants reflecting their European, Asian, and African admixture. Precision medicine requires that African populations begin to capture their own pharmacogenetic SNPs as they cannot always infer with absolute certainty from Asian and European populations. In the current historical moment of the COVID-19 pandemic, we also underscore that the spectrum of drugs interacting with warfarin will likely increase, given the systemic and cardiovascular effects of COVID-19, and the anticipated influx of COVID-19 medicines in the near future. This observational clinical pharmacogenomics study of warfarin, together with past precision medicine research, collectively, lends strong support for incorporation of pharmacogenetic profiling in clinical settings in African patients for effective and safe administration of therapeutics.

Pharmacokinetic-pharmacodynamic modelling of atazanavir in hair among adolescents on antiretroviral treatment in Zimbabwe.

BACKGROUND: Drug potency is a pharmacological parameter defining dose or concentration of drug required to obtain 50% of the drug's maximal effect. Pharmacokinetic-pharmacodynamic modelling and simulation allows estimation of potency and evaluate strategies improving treatment outcome. The objective of our study is to determine potency of atazanavir in hair, defined as atazanavir level in hair associated with 50% probability of failing to achieve viral load below 1000 copies/ml among adolescents, and explore the effect of participant specific variables on potency. METHODS: A secondary analysis was performed on data from a previous study conducted in HIV-infected adolescents failing 2nd line ART from Harare central hospital, Zimbabwe, between 2015 and 2016. We simulated atazanavir concentrations in hair using NONMEM (version 7.3) ADVAN 13, based on a previously established pharmacokinetic model. Logistic regression methods were used for PKPD analysis. Simulations utilising PKPD model focused on estimation of potency and exploring the effect of covariates. RESULTS: The potency of atazanavir in hair was found to be 4.5 ng/mg hair before adjusting for covariate effects. Participants at three months follow-up, reporting adequate adherence, having normal BMI-for-age, and cared for by mature guardians had increased potency of atazanavir in hair of 2.6 ng/mg, however the follow-up event was the only statistically significant factor at 5% level. CONCLUSION: Atazanavir in hair in the range 2.6 to 4.5 ng/mg is associated with above 50% probability of early viral load suppression. Adherence monitoring to adolescents with lower potency of atazanavir is recommended. The effect self-reported adherence level, BMI-for-age, and caregiver status require further evaluation.

Pain management strategies among cervical cancer patients in Zimbabwe.

Aim: To describe pain management regulations, prevalence of pain and pain management practices in a Zimbabwean setting. Materials & methods: A multi-methods approach was used, consisting of: policy and guideline review; review of 410 cervical cancer patient records for pain symptoms and pain management data; and semistructured interviews with oncology healthcare practitioners. Results: We found a lack of policies that are specific for cervical cancer pain management. Although prevalence of pain was 68% (n = 278), only 42% of the patient records indicated pain drugs had been prescribed. Barriers to pain management included inadequate use of pain assessment tools, inaccessibility of key drugs and limited capacity. Conclusion: Cancer pain management in Zimbabwe can be improved by tailoring assessment protocols, improving drug accessibility and strengthening healthcare systems.

Lay abstract Although cancer pain has potential life-altering impact, it is not well studied in developing countries. This study aims to report on cancer pain management in Zimbabwe by reviewing policies of pain management, patient records for prevalence and assessing the practices of cancer pain management, using 410 cervical cancer patients as a model. In total, 278 (68%) cancer patients presented with pain, yet only 42% of patient records had documented prescribed pain management. We report that these findings can be consequences of restrictive policies, inadequate patient pain assessment, inaccessible pain drugs, unrecorded prescriptions and limitations of resources in the facility. Our study is important because it identifies gaps that can be addressed to improve care for cancer patients in resource-limited settings.

Clinically relevant enantiomer specific R- and S-praziquantel pharmacokinetic drug-drug interactions with efavirenz and ritonavir.

We conducted a clinical study to determine the effect of efavirenz and ritonavir on the pharmacokinetics of R- and S-PZQ in healthy male participants. This was toward evaluating the risk of drug-drug interactions, which may occur after PZQ administration to HIV patients on efavirenz or ritonavir containing regimens. A non-randomized, open-label, single-dose, one sequence crossover study with 2 arms was conducted. We gave 26 healthy volunteers a single oral dose of 40 mg/kg PZQ followed by a daily oral dose of either 400 mg efavirenz or 100 mg ritonavir for 14 consecutive days. On day 14, they ingested a single 40 mg/kg dose of PZQ. We measured plasma levels up to 12 h on day 1 and day 14. Samples were analyzed by LC-MS. Pharmacokinetic analysis was conducted in WinNonlin to determine the primary endpoints (plasma T1/2 , Cmin , and AUC). Efavirenz had a significant effect on the pharmacokinetics of PZQ (p < .05), reducing the AUC by 4-fold (1213.15 vs. 281.35 h·ng/ml for R-PZQ and 5669 vs. 871.84 h·ng/ml for S-PZQ). Ritonavir had no significant effect on R-PZQ but increased the AUC 2-fold for S-PZQ (p < .05) (4154.79 vs. 7291.05 h·ng/ml). Using PZQ in HIV patients needs investigation, as there is a risk of both treatment failure and adverse effects because of induction and inhibition, respectively.

High-risk HPV genotypes in Zimbabwean women with cervical cancer: Comparative analyses between HIV-negative and HIV-positive women.

BACKGROUND: High-risk human papillomavirus HPV (HR-HPV) modifies cervical cancer risk in people living with HIV, yet African populations are under-represented. We aimed to compare the frequency, multiplicity and consanguinity of HR-HPVs in HIV-negative and HIV-positive Zimbabwean women. METHODS: This was a cross-sectional study consisting of women with histologically confirmed cervical cancer attending Parirenyatwa Group of Hospitals in Harare, Zimbabwe. Information on HIV status was also collected for comparative analysis. Genomic DNA was extracted from 258 formalin fixed paraffin embedded tumour tissue samples, and analysed for 14 HR-HPV genotypes. Data was analysed using Graphpad Prism and STATA. RESULTS: Forty-five percent of the cohort was HIV-positive, with a median age of 51 (IQR = 42-62) years. HR-HPV positivity was detected in 96% of biospecimens analysed. HPV16 (48%), was the most prevalent genotype, followed by HPV35 (26%), HPV18 (25%), HPV58 (11%) and HPV33 (10%), irrespective of HIV status. One third of the cohort harboured a single HPV infection, and HPV16 (41%), HPV18 (21%) and HPV35 (21%) were the most prevalent. HIV status did not influence the prevalence and rate of multiple HPV infections (p>0.05). We reported significant (p<0.05) consanguinity of HPV16/18 (OR = 0.3; 95% CI = 0.1-0.9), HPV16/33 (OR = 0.3; 95% CI = 0.1-1.0), HPV16/35 (OR = 3.3; 95% CI = 2.0-6.0), HPV35/51 (OR = 6.0; 95%CI = 1.8-15.0); HPV39/51 (OR = 6.4; 95% CI = 1.8-15), HPV31/52 (OR = 6.2; 95% CI = 1.8-15), HPV39/56 (OR = 11 95% CI = 8-12), HPV59/68 (OR = 8.2; 95% CI = 5.3-12.4), HPV66/68 (OR = 7; 95% CI = 2.4-13.5), independent of age and HIV status. CONCLUSION: We found that HIV does not influence the frequency, multiplicity and consanguinity of HR-HPV in cervical cancer. For the first time, we report high prevalence of HPV35 among women with confirmed cervical cancer in Zimbabwe, providing additional evidence of HPV diversity in sub-Saharan Africa. The data obtained here probes the need for larger prospective studies to further elucidate HPV diversity and possibility of selective pressure on genotypes.

Impact of acute, oral ingestion of hypoxoside from African potato on hepatic and renal function tests in HIV infected patients on combination antiretroviral therapy.

OBJECTIVES: African potato (hypoxis hemerocallidea) is used against HIV to enhance immune-function, although no studies have evaluated its use in HIV infected individuals on combination antiretroviral therapy. The study aimed to evaluate the acute effects of orally administered hypoxoside, a constituent of African potato, on the hepatic and renal function in HIV infected individuals on tenofovir disoproxil fumarate/ lamivudine/ efavirenz regimen. METHODS: This was an open-label, two-period, fixed-sequence, pre-post test study, pilot design. Ethical approval was obtained from Medical Research Council of Zimbabwe (MRCZ A/2045) and Medicines Control Authority of Zimbabwe (MCAZ CT134/2016). Blood samples were collected before and after administration of African potato tablets. Tablets were administered orally once daily at 15mg/ kg hypoxoside for 10 days. Hepatic function tests (ALT, AST, ALP, GGT, albumin, total/ direct bilirubin); renal function tests (eGFR, blood urea nitrogen, creatinine), serum electrolytes (sodium, potassium, chloride) were assayed. STATA was used for statistical analysis. RESULTS: Twenty-six participants were enrolled (85% female). Median age (range) was 43 (28-52) years. Most had overweight Body Mass Index (46%) and were married (54%). No statistical difference was noted during hypoxoside for AST/ ALT/ ALP/ GGT/ albumin/ bilirubin. There were no changes in creatinine/ eGFR/ electrolytes. A mean significant increase in total protein (p=0.04) and decrease in blood urea nitrogen (p=0.04) were noted. CONCLUSION: Short-term exposure to hypoxoside from African potato appeared safe and was not associated with clinically significant changes in hepatic, renal function tests/electrolytes. There is further need to evaluate extent of systemic exposure during long-term use in a larger population.

Short Communication: Higher Tenofovir Concentrations in Hair Are Associated with Decreases in Viral Load and Not Self-Reported Adherence in HIV-Infected Adolescents with Second-Line Virological Treatment Failure.

Objective methods of measuring antiretroviral adherence are limited. We assessed the relationship between tenofovir disoproxil fumarate (TDF) hair concentrations, self-reported adherence, and virological outcomes in HIV-infected adolescents in Harare, Zimbabwe. HIV-infected adolescents on atazanavir/ritonavir-based second-line treatment for >6 months with viral load (VL) ≥1,000 copies/mL were randomized to either modified directly administered antiretroviral therapy (mDAART) or standard of care. Hair and VL samples were collected at baseline and after 90 days. Treatment outcome was defined as TDF concentrations in hair. Virological suppression was defined as VL <1,000 copies/mL. Thirty-four adolescents had TDF concentrations measured at baseline and follow-up. Mean (median); range age was 16 (16); 13-18 years and 53% were females. Nineteen (56%) were randomized to mDAART. Mean (SD); range TDF concentrations were 0.03 (0.04); 0-0.17 ng/mg hair and 0.06 (0.06); 0-0.3 ng/mg hair at baseline and follow-up, respectively. Higher TDF concentrations were associated with decreased VL [regression coefficient (RC) 0.8; 95% confidence interval (CI) 0.7-1.0; p = .008] and mDAART (RC 0.5; 95% CI 0.3-1.0; p = .04), but were not associated with self-reported adherence and virological suppression (VL <1,000 copies/mL). Higher TDF hair concentrations were observed with virological decrease and an adherence intervention. Hair antiretroviral concentrations could be useful in triggering adherence interventions among adolescents with second-line virological failure.

Brief Report: Ritonavir Concentrations in Hair Predict Virologic Outcomes in HIV-Infected Adolescents With Virologic Failure on Atazanavir-Based or Ritonavir-Based Second-Line Treatment.

BACKGROUND: Suboptimal adherence to antiretroviral therapy (ART) is responsible for most virologic failure among adolescents with HIV. Methods for objectively measuring adherence to ART are limited. This study assessed the association between ritonavir concentrations in hair and self-reported adherence and modified directly administered ART on virologic outcomes among HIV-infected adolescents who were virologically failing second-line ART in Harare, Zimbabwe. METHODS: HIV-infected adolescents on atazanavir-based or ritonavir-based second-line treatment for >6 months with viral load ≥1000 copies/mL were randomized to either modified directly administered ART (mDAART) plus standard of care (intervention) or standard of care alone (control). Questionnaires were administered; viral load and hair samples were collected at baseline and after 90 days. Virological suppression was defned as <1000 copies/mL after follow-up. RESULTS: Fifty adolescents (13-19 years) were enrolled in the study, and 42 adolescents had ritonavir concentrations measured in hair at baseline and at 90 days. Twenty-three participants (46%) were randomized to mDAART. Viral load suppression at follow-up [regression coefficient (standard error): -0.3 (0.1); 95% confidence interval (CI): -0.5 to -0.06; P = 0.01], self-reported adherence at follow-up [regression coefficient (standard error): 0.01 (0.005); 95% CI: 0.004 to 0.02; P = 0.006], and being male sex [regression coefficient (standard error): 0.3 (0.1); 95% CI: 0.08 to 0.5; P = 0.008] were associated with ritonavir concentrations in hair. The intervention, mDAART, was not associated with ritonavir concentrations [regression coefficient (standard error) 0.2 (0.1); 95% CI: -0.07 to 0.4; P = 0.2]. CONCLUSIONS: Ritonavir concentrations in hair predicted virological suppression and were associated with self-reported adherence and being male in this cohort of adolescents with treatment failure to atazanavir-based or ritonavir-based second-line ART. Measuring ritonavir concentrations in hair in adolescents on protease inhibitor-based regimens could assess adherence in this vulnerable group to avert subsequent virologic failure.

A survey of ethnomedicinal plants used to treat cancer by traditional medicine practitioners in Zimbabwe.

BACKGROUND: Traditional medicine plays an important role in health care provision in the developing world. A number of cancer patients have been found to be using traditional medicine as primary therapy and/or as complementary medicine. Cancer is one of the leading causes of morbidity and mortality globally among the non-communicable diseases. The aim of this study was to identify the plants used by traditional medicine practitioners (TMPs) in Zimbabwe to treat cancer. METHODS: A structured questionnaire was used to interview consenting registered TMPs on ethnomedicinal plants they use to treat cancer. A review of published literature on the cited plants was also carried out. The practitioners were asked about the plants that they use to treat cancer, the plant parts used, type of cancer treated, other medicinal uses of the plants and preparation and administration of the plant parts. RESULTS: Twenty (20) TMPs took part in the study. A total of 18 medicinal plant species were cited. The commonly treated types of cancer were breast, prostate, colon, skin and blood cancers with most plants being used to treat skin, blood and breast cancers, respectively. Of the medicinal plants cited, 44.4% were used to treat all cancer types. The most used plant parts were the roots (72.2%) and leaves (72.2%) followed by the bark (38.9%). The medicinal plants were used for multiple ailments. The most common plant preparation methods were infusion (72.2%) and decoction (66.7%) and the oral route of administration, as extracts and powder put in tea and porridge, was the most used. CONCLUSION: The frequently used plant parts were leaves and roots. The traditional uses of the medicinal plants cited in this study resonate well with their reported uses from other ethnopharmacological studies done in other parts of the world. The plants used by TMPs to treat cancer in Zimbabwe, if adequately explored, can be instrumental in the discovery and development of cancer drugs.

African potato (Hypoxis hemerocallidea): a systematic review of its chemistry, pharmacology and ethno medicinal properties.

BACKGROUND: African Potato (hypoxis hemerocallidea), is used for enhancing immune system in Southern Africa. It is among the plants of intense commercial and scientific interest; hence, the aim of this study was to describe its chemistry and pharmacology. METHODS: PubMed, Cochrane Controlled Trials Register (CENTRAL) and Google Scholar were searched independently for relevant literature. The last search occurred in October 2018. Other research material was obtained from Google. The following search terms were used, but not limited to: "African Potato", "hypoxis", "hemerocallidea", "rooperol." Articles that were explaining the chemistry and pharmacology of hypoxis hemerocallidea were included. RESULTS: Thirty articles from PubMed, Cochrane and Google Scholar were eligible. Three webpages were included from Google. Results showed that the tuberous rootstock (corm) of African Potato is used traditionally to treat wasting diseases, testicular tumours, insanity, barrenness, impotency, bad dreams, intestinal parasites, urinary infection, cardiac disease and enhancing immunity. The plant contains hypoxoside, which is converted rapidly to a potent antioxidant, rooperol in the gut. The corm contains sterols, sterol glycosides, stanols, terpenoids, saponins, cardiac glycosides, tannins and reducing sugars. A dose of 15 mg/kg/day of hypoxoside is reportedly therapeutic. Preclinical studies of African Potato have shown immunomodulation, antioxidant, antinociceptive, hypoglycaemic, anti-inflammatory, anticonvulsant, antibacterial, uterolytic, antimotility, spasmolytic and anticholinergic effects. The common side effects of African Potato are nausea and vomiting, which subside over time. In vitro, African Potato demonstrated inhibitory effects on CYP1A2, 2C9, 2D6, 3A4, 3A5, CYP19-metabolism and induction of P-glycoprotein. In vivo, it did not alter the pharmacokinetics of efavirenz or lopinavir/ritonavir. CONCLUSION: African Potato is mainly used as an immunostimulant. The exact mechanisms of action for all the pharmacological actions are unknown. More research is required to substantiate claims regarding beneficial effects. There are many research gaps that require investigation including pharmacokinetic interactions with conventional drugs, especially those used in HIV/AIDS.

In vitro and in vivo human metabolism and pharmacokinetics of S- and R-praziquantel.

Racemic praziquantel (PZQ) is the drug of choice for the treatment of schistosomiasis. R-Praziquantel (R-PZQ) has been shown as the therapeutic form, whereas S-PZQ is less efficacious and responsible for the bitter taste of the tablet. This study aimed at investigating the metabolism of R- and S-PZQ as this could have implications on efficacy and safety of racemate and R-PZQ specific formulations under development. In vitro CYP reaction phenotyping assay using 10 recombinant CYP (rCYP) isoenzymes showed hepatic CYP1A2, 2C19, 2D6, 3A4, and 3A5 were the major enzymes involved in metabolism of PZQ. Enzyme kinetic studies were performed by substrate depletion and metabolite formation methods, by incubating PZQ and its R- or S-enantiomers in human liver microsomes (HLM) and the rCYP enzymes. The effect of selective CYP inhibitors on PZQ metabolism was assessed in HLM. CYP1A2, 2C19, and 3A4 exhibited different catalytic activity toward PZQ, R- and S-enantiomers. Metabolism of R-PZQ was mainly catalyzed by CYP1A2 and CYP2C19, whereas metabolism of S-PZQ was mainly by CYP2C19 and CYP3A4. Based on metabolic CLint obtained through formation of hydroxylated metabolites, CYP3A4 was estimated to contribute 89.88% to metabolism of S-PZQ using SIMCYP® IVIVE prediction. Reanalysis of samples from a human PZQ-ketoconazole (KTZ) drug-drug interaction pharmacokinetic study confirmed these findings in that KTZ, a potent inhibitor of CYP3A, selectively increased area under the curve of S-PZQ by 68% and that of R-PZQ by just 9%. Knowledge of enantioselective metabolism will enable better understanding of variable efficacy of PZQ in patients and the R-PZQ formulation under development.

A population pharmacokinetic model is beneficial in quantifying hair concentrations of ritonavir-boosted atazanavir: a study of HIV-infected Zimbabwean adolescents.

BACKGROUND: Adolescents experience higher levels of non-adherence to HIV treatment. Drug concentration in hair promises to be reliable for assessing exposure to antiretroviral (ARV) drugs. Pharmacokinetic modelling can explore utility of drug in hair. We aimed at developing and validating a pharmacokinetic model based on atazanavir/ritonavir (ATV/r) in hair and identify factors associated with variabilities in hair accumulation. METHODS: We based the study on secondary data analysis whereby data from a previous study on Zimbabwean adolescents which collected hair samples at enrolment and 3 months follow-up was used in model development. We performed model development in NONMEM (version 7.3) ADVAN 13. RESULTS: There is 16% / 18% of the respective ATV/r in hair as a ratio of steady-state trough plasma concentrations. At follow-up, we estimated an increase of 30% /42% of respective ATV/r in hair. We associated a unit increase in adherence score with 2% increase in hair concentration both ATV/r. Thinner participants had 54% higher while overweight had 21% lower atazanavir in hair compared to normal weight participants. Adolescents receiving care from fellow siblings had atazanavir in hair at least 54% less compared to other forms of care. CONCLUSION: The determinants of increased ATV/r concentrations in hair found in our analysis are monitoring at follow up event, body mass index, and caregiver status. Measuring drug concentration in hair is feasibly accomplished and could be more accurate for monitoring ARV drugs exposure.

Healthcare Professionals' Knowledge of Pharmacogenetics and Attitudes Towards Antimicrobial Utilization in Zambia: Implications for a Precision Medicine Approach to Reducing Antimicrobial Resistance.

Introduction: Sub-Saharan Africa and other low- and middle-income countries (LMICs) have the highest rates of antimicrobial resistance (AMR) driven by high rates of antimicrobial utilization. This is a concern as AMR appreciably increases morbidity, mortality and costs. Pharmacogenetics (PGx) and precision medicine are emerging approaches to combat AMR. Consequently, as a first step there is a need to assess AMR knowledge and attitudes, and knowledge of PGx, among healthcare professionals and use the findings to guide future interventions. Methodology: We conducted a cross-sectional study involving 304 healthcare professionals at tertiary hospitals in Lusaka, Zambia. Structural Equation Modeling (SEM) was used to analyze relationships among latent variables. Results: Overall correctness of answers concerning AMR among healthcare professionals was 60.4% (7/11). Knowledge of pharmacogenetics was low (38%). SEM showed that high AMR knowledge score correlated with a positive attitude toward combating AMR (p < 0.001). Pharmacists had relatively higher AMR knowledge scores (mean = 7.67, SD = 1.1), whereas nurses had lower scores (mean = 5.57, SD = 1.9). A minority of respondents [31.5% (n = 95)] indicated that poor access to local antibiogram data promoted AMR, with the majority [56.5% (n = 190)] responding that poor adherence to prescribed antimicrobials can lead to AMR. Pharmacists had the highest scores for attitude (mean = 5.60, SD = 1.6) whereas nurses had the lowest scores (mean = 4.02, SD = 1.4). Conclusion: AMR knowledge and attitudes, as well as knowledge on PGx among healthcare professionals in Zambia, is sub-optimal and has the potential to affect the uptake of precision medicine approaches to reduce AMR rates. Educational and positive behavioral change interventions are required to address this and in future, we will be seeking to introduce these to improve the use of antimicrobials.

Prevalence of Traditional Medicine Use during Pregnancy, at Labour and for Postpartum Care in a Rural Area in Zimbabwe.

OBJECTIVES: The aim of this study was to determine the prevalence and types of traditional medicine used during pregnancy, at labour and for postpartum care by women in rural Zimbabwe. RESEARCH DESIGN: A cross-sectional survey was conducted on 398 women from two rural districts in Zimbabwe. Data on socio-demography, pregnancy related information as well as traditional medicine use patterns was collected using a structured interviewer administered questionnaire. Convenient sampling was used to recruit women of childbearing age who were either pregnant at the time of the study, or had previously given birth. RESULTS: The prevalence of traditional medicine used during pregnancy and at labour was 69.9% and only 17.3% used these medicines for postpartum care. During pregnancy, 27.7% used soil from a mole hill, 21.6% used elephant dung, and 13.3% used Fadogia ancylantha. These medicines were mainly used to facilitate labour (43.5%), avoid tears/stitches (19.7%), make delivery easy and safe (18.3%) and to avoid prolonged labour (5%). Only 9% of the participants however reported to have experienced adverse effects from using traditional medicines. CONCLUSION: The use of traditional remedies in different forms during pregnancy and at labour was very common as confirmed by the high prevalence rate of 69.9%. Some of the women however used more than one type of traditional medicine during pregnancy, labour and for postpartum care. The exact effects of some of these medicines on both the mother and infant however, are not known, and there is therefore a need for them to be studied in greater detail.