A Systematic Review of the Role of Proprietary and Patent Medicine Vendors in Healthcare Provision in Nigeria

Background

Interventions to reduce the burden of disease and mortality in sub-Saharan Africa increasingly recognize the important role that drug retailers play in delivering basic healthcare services. In Nigeria, owner-operated drug retail outlets, known as patent and proprietary medicine vendors (PPMVs), are a main source of medicines for acute conditions, but their practices are not well understood. Greater understanding of the role of PPMVs and the quality of care they provide is needed in order to inform ongoing national health initiatives that aim to incorporate PPMVs as a delivery mechanism.

Objective and Methods

This paper reviews and synthesizes the existing published and grey literature on the characteristics, knowledge and practices of PPMVs in Nigeria. We searched published and grey literature using a number of electronic databases, supplemented with website searches of relevant international agencies. We included all studies providing outcome data on PPMVs in Nigeria, including non-experimental studies, and assessed the rigor of each study using the WHO-Johns Hopkins Rigor scale. We used narrative synthesis to evaluate the findings.

Results

We identified 50 articles for inclusion. These studies provided data on a wide range of PPMV outcomes: training; health knowledge; health practices, including drug stocking and dispensing, client interaction, and referral; compliance with regulatory guidelines; and the effects of interventions targeting PPMVs. In general, PPMVs have low health knowledge and poor health treatment practices. However, the literature focuses largely on services for adult malaria, and little is known about other health areas or services for children.

Conclusions

This review highlights several concerns with the quality of the private drug retail sector in Nigeria, as well as gaps in the existing evidence base. Future research should adopt a more holistic view of the services provided by PPMV shops, and evaluate intervention strategies that may improve the services provided in this sector.     

Prevalence of Malaria Parasitemia and Purchase of Artemisinin-Based Combination Therapies (ACTs) among Drug Shop Clients in Two Regions in Tanzania with ACT Subsidies

Background

Throughout Africa, many people seek care for malaria in private-sector drug shops where diagnostic testing is often unavailable. Recently, subsidized artemisinin-based combination therapies (ACTs), a first-line medication for uncomplicated malaria, were made available in these drug shops in Tanzania. This study assessed the prevalence of malaria among and purchase of ACTs by drug shop clients in the setting of a national ACT subsidy program and sub-national drug shop accreditation program.

Method and Findings

A cross-sectional survey of drug shop clients was performed in two regions in Tanzania, one with a government drug shop accreditation program and one without, from March-May, 2012. Drug shops were randomly sampled from non-urban districts. Shop attendants were interviewed about their education, training, and accreditation status. Clients were interviewed about their symptoms and medication purchases, then underwent a limited physical examination and laboratory testing for malaria. Malaria prevalence and predictors of ACT purchase were assessed using univariate analysis and multiple logistic regression. Amongst 777 clients from 73 drug shops, the prevalence of laboratory-confirmed malaria was 12% (95% CI: 6–18%). Less than a third of clients with malaria had purchased ACTs, and less than a quarter of clients who purchased ACTs tested positive for malaria. Clients were more likely to have purchased ACTs if the participant was <5 years old (aOR: 6.6; 95% CI: 3.9–11.0) or the shop attendant had >5 years, experience (aOR: 2.8; 95% CI: 1.2–6.3). Having malaria was only a predictor of ACT purchase in the region with a drug shop accreditation program (aOR: 3.4; 95% CI: 1.5–7.4).

Conclusion

Malaria is common amongst persons presenting to drug shops with a complaint of fever. The low proportion of persons with malaria purchasing ACTs, and the high proportion of ACTs going to persons without malaria demonstrates a need to better target who receives ACTs in these drug shops.     

Increased Access to Care and Appropriateness of Treatment at Private Sector Drug Shops with Integrated Management of Malaria,Pneumonia and Diarrhoea: A Quasi-Experimental Study in Uganda

Introduction

Drug shops are a major source of care for children in low income countries but they provide sub-standard care. We assessed the feasibility and effect on quality of care of introducing diagnostics and pre-packaged paediatric-dosage drugs for malaria, pneumonia and diarrhoea at drug shops in Uganda.

Methods

We adopted and implemented the integrated community case management (iCCM) intervention within registered drug shops. Attendants were trained to perform malaria rapid diagnostic tests (RDTs) in each fever case and count respiratory rate in each case of cough with fast/difficult breathing, before dispensing recommended treatment. Using a quasi-experimental design in one intervention and one non-intervention district, we conducted before and after exit interviews for drug seller practices and household surveys for treatment-seeking practices in May–June 2011 and May–June 2012. Survey adjusted generalized linear models and difference-in-difference analysis was used.

Results

3759 (1604 before/2155 after) household interviews and 943 (163 before/780 after) exit interviews were conducted with caretakers of children under-5. At baseline, no child at a drug shop received any diagnostic testing before treatment in both districts. After the intervention, while no child in the non-intervention district received a diagnostic test, 87.7% (95% CI 79.0–96.4) of children with fever at the intervention district drug shops had a parasitological diagnosis of malaria, prior to treatment. The prevalence ratios of the effect of the intervention on treatment of cough and fast breathing with amoxicillin and diarrhoea with ORS/zinc at the drug shop were 2.8 (2.0–3.9), and 12.8 (4.2–38.6) respectively. From the household survey, the prevalence ratio of the intervention effect on use of RDTs was 3.2 (1.9–5.4); Artemisinin Combination Therapy for malaria was 0.74 (0.65–0.84), and ORS/zinc for diarrhoea was 2.3 (1.2–4.7).

Conclusion

iCCM can be utilized to improve access and appropriateness of care for children at drug shops.     

Has Tanzania Embraced the Green Leaf? Results from Outlet and Household Surveys before and after Implementation of the Affordable Medicines Facility -Malaria

Background

The Affordable Medicines Facility - malaria (AMFm) is primarily an artemisinin combination therapy (ACT) subsidy, aimed at increasing availability, affordability, market share and use of quality-assured ACTs (QAACTs). Mainland Tanzania was one of eight national scale programmes where AMFm was introduced in 2010. Here we present findings from outlet and household surveys before and after AMFm implementation to evaluate its impact from both the supply and demand side.

Methods

Outlet surveys were conducted in 49 randomly selected wards throughout mainland Tanzania in 2010 and 2011, and data on outlet characteristics and stocking patterns were collected from outlets stocking antimalarials. Household surveys were conducted in 240 randomly selected enumeration areas in three regions in 2010 and 2012. Questions about treatment seeking for fever and drugs obtained were asked of individuals reporting fever in the previous two weeks.

Results

The availability of QAACTs increased from 25.5% to 69.5% among all outlet types, with the greatest increase among pharmacies and drug stores, together termed specialised drug sellers (SDSs), where the median QAACT price fell from $5.63 to $0.94. The market share of QAACTs increased from 26.2% to 42.2%, again with the greatest increase in SDSs. Household survey results showed a shift in treatment seeking away from the public sector towards SDSs. Overall, there was no change in the proportion of people with fever obtaining an antimalarial or ACT from baseline to endline. However, when broken down by treatment source, ACT use increased significantly among clients visiting SDSs.

Discussion

Unchanged ACT use overall, despite increases in QAACT availability, affordability and market share in the private sector, reflected a shift in treatment seeking towards private providers. The reasons for this shift are unclear, but likely reflect both persistent stockouts in public facilities, and the increased availability of subsidised ACTs in the private sector.     

Piloting the Global Subsidy: The Impact of Subsidized Artemisinin-Based Combination Therapies Distributed through Private Drug Shops in Rural Tanzania

Background

WHO estimates that only 3% of fever patients use recommended artemisinin-based combination therapies (ACTs), partly reflecting their high prices in the retail sector from where many patients seek treatment. To overcome this challenge, a global ACT subsidy has been proposed. We tested this proposal through a pilot program in rural Tanzania.

Methods/Principal Findings

Three districts were assigned to serve either as a control or to receive the subsidy plus a package of supporting interventions. From October 2007, ACTs were sold at a 90% subsidy through the normal private supply chain to intervention district drug shops. Data were collected at baseline and during intervention using interviews with drug shop customers, retail audits, mystery shoppers, and audits of public and NGO facilities.The proportion of consumers in the intervention districts purchasing ACTs rose from 1% at baseline to 44.2% one year later (p<0.001), and was significantly higher among consumers purchasing for children under 5 than for adults (p = 0.005). No change in ACT usage was observed in the control district. Consumers paid a mean price of $0.58 for ACTs, which did not differ significantly from the price paid for sulphadoxine-pyrimethamine, the most common alternative. Drug shops in population centers were significantly more likely to stock ACTs than those in more remote areas (p<0.001).

Conclusions

A subsidy introduced at the top of the private sector supply chain can significantly increase usage of ACTs and reduce their retail price to the level of common monotherapies. Additional interventions may be needed to ensure access to ACTs in remote areas and for poorer individuals who appear to seek treatment at drug shops less frequently.

Trial Registration

Controlled-Trials.com ISRCTN39125414.     

The Impact of Artemisinin Combination Therapy and Long-Lasting Insecticidal Nets on Forest Malaria Incidence in Tribal Villages of India, 2006–2011

Introduction

New tools for malaria control, artemisinin combination therapy (ACT) and long-lasting insecticidal nets (LLINs) were recently introduced across India. We estimated the impact of universal coverage of ACT and ACT plus LLINs in a setting of hyperendemic, forest malaria transmission.

Methods

We reviewed data collected through active and passive case detection in a vaccine trial cohort of 2,204 tribal people residing in Sundargarh district, Odisha between 2006 and 2011. We compared measures of transmission at the village and individual level in 2006–2009 versus 2010–2011 after ACT (in all villages) and LLINs (in three villages) were implemented.

Results

During 2006–2009 malaria incidence per village ranged from 156–512 per 1000 persons per year and slide prevalence ranged from 28–53%. Routine indoor residual spray did not prevent seasonal peaks of malaria. Post-intervention impact in 2010–2011 was dramatic with ranges of 14–71 per 1000 persons per year and 6–16% respectively. When adjusted for village, ACT alone decreased the incidence of malaria by 83% (IRR 0.17, 95%CI: 0.10, 0.27) and areas using ACT and LLINs decreased the incidence of malaria by 86% (IRR 0.14, 95%CI: 0.05, 0.38). After intervention, the age of malaria cases, their parasite density, and proportion with fever at the time of screening increased.

Conclusions

ACT, and LLINs along with ACT, effectively reduced malaria incidence in a closely monitored population living in a forest ecotype. It is unclear whether LLINs were impactful when prompt and quality antimalarial treatment was available. In spite of universal coverage, substantial malaria burden remained.     

Care-Seeking and Management of Common Childhood Illnesses in Tanzania – Results from the 2010 Demographic and Health Survey

Background

Malaria, pneumonia and diarrhoea continue to kill millions of children in Africa despite the available and effective treatments. Correct diagnosis and prompt treatment with effective drugs at the first option consulted for child care is crucial for preventing severe disease and death from these illnesses. Using the 2010 Demographic and Health Survey data, the present study aims to assess care-seeking and management of suspected malaria, pneumonia and diarrhoea at various health care facilities in Tanzania.

Methods

We analyzed data for 8176 children born within a 5 years period preceding the survey.The information was collected by interviewing 5519 women aged 15–49 years in 10,300 households selected from 475 sample points throughout Tanzania.

Results

The most common first option for child care was PHC facilities (54.8%), followed by private pharmacies (23.4%). These were more commonly utilized in rural compared to urban areas: 61.2% versus 34.5% for PHC facilities, and 26.5% versus 17.7% for pharmacies. Women in urban areas and those with higher level of education more commonly utilized higher level hospitals and private facilities as their first option for child care. Only one in four children with fever had received a blood test during the illness with lowest proportion being reported among children solely attended at PHC facilities. Use of abandoned antimalarial drugs for the treatment of suspected malaria was also observed in public health facilities and antibiotics use for diarrhoea treatment was high (49.0%).

Conclusions

PHC facilities and pharmacies most commonly provided sub-optimal care. These facilities were more commonly utilized as the first option for child care in rural areas and among the poor and non-educated families. These are groups with the highest child mortality, which calls for interventions’ targeting improvement of care at these facilities to further reduce child mortality from treatable illnesses in Tanzania.     

Feasibility of Distributing Rapid Diagnostic Tests for Malaria in the Retail Sector: Evidence from an Implementation Study in Uganda

Background

Despite the benefits of malaria diagnosis, most presumed malaria episodes are never tested. A primary reason is the absence of diagnostic tests in retail establishments, where many patients seek care. Malaria rapid diagnostic tests (RDTs) in drug shops hold promise for guiding appropriate treatment. However, retail providers generally lack awareness of RDTs and training to administer them. Further, unsubsidized RDTs may be unaffordable to patients and unattractive to retailers. This paper reports results from an intervention study testing the feasibility of RDT distribution in Ugandan drug shops.

Methods and Findings

92 drug shops in 58 villages were offered subsidized RDTs for sale after completing training. Data on RDT purchases, storage, administration and disposal were collected, and samples were sent for quality testing. Household surveys were conducted to capture treatment outcomes. Estimated daily RDT sales varied substantially across shops, from zero to 8.46 RDTs per days. Overall compliance with storage, treatment and disposal guidelines was excellent. All RDTs (100%) collected from shops passed quality testing. The median price charged for RDTs was 1000USH ($0.40), corresponding to a 100% markup, and the same price as blood slides in local health clinics. RDTs affected treatment decisions. RDT-positive patients were 23 percentage points more likely to buy Artemisinin Combination Therapies (ACTs) (p = .005) and 33.1 percentage points more likely to buy other antimalarials (p<.001) than RDT-negative patients, and were 5.6 percentage points more likely to buy ACTs (p = .05) and 31.4 percentage points more likely to buy other antimalarials (p<.001) than those not tested at all.

Conclusions

Despite some heterogeneity, shops demonstrated a desire to stock RDTs and use them to guide treatment recommendations. Most shops stored, administered and disposed of RDTs properly and charged mark-ups similar to those charged on common medicines. Results from this study suggest that distributing RDTs through the retail sector is feasible and can reduce inappropriate treatment for suspected malaria.     

Frequency and Risk Factors for Under- and Over-Treatment in Stroke Prevention for Patients with Non-Valvular Atrial Fibrillation in General Practice

Objective

To determine adequacy of antithrombotic treatment in patients with non-valvular atrial fibrillation. To determine risk factors for under- and over-treatment.

Design

Retrospective, cross-sectional study of electronic health records from 36 general practitioners in 2008.

Setting

General practice in the Netherlands.

Subjects

Primary care physicians (n = 36) and patients (n = 981) aged 65 years and over.

Main Outcome Measures

Rates of adequate, under and over-treatment, risk factors for under and over-treatment.

Results

Of the 981 included patients with a mean of age 78, 18% received no antithrombotic treatment (under-treatment), 13% received antiplatelet drugs and 69% received oral anticoagulation (OAC). Further, 43% of the included patients were treated adequately, 26% were under-treated, and 31% were over-treated. Patients with a previous ischaemic stroke were at high risk for under-treatment (OR 2.4, CI 1.6–3.5), whereas those with contraindications for OAC were at high risk for over-treatment (OR 37.0, CI 18.1–79.9). Age over 75 (OR 0.2, CI: 0.1–0.3]), diabetes (OR 0.1, CI: 0.1–0.3), heart failure (OR 0.2, CI: 0.1–0.3), hypertension (OR 0.1, CI: 0.1–0.2) and previous ischaemic stroke (OR 0.04, CI: 0.02–0.11) protected against over-treatment.

Conclusions

In general practice, CHADS₂-criteria are being used, but the antithrombotic treatment of patients with atrial fibrillation frequently deviates from guidelines on this topic. Patients with previous stroke are at high risk of not being prescribed OAC. Contraindications for OAC, however, seem to be frequently overlooked.     

Improved STD Syndrome Management by a Network of Clinicians and Pharmacy Workers in Peru: The PREVEN Network

Background

Sexually Transmitted diseases (STD) syndrome management has been one cornerstone of STD treatment. Persons with STD symptoms in many countries, especially those with limited resources, often initially seek care in pharmacies. The objective of the study was to develop and evaluate an integrated network of physicians, midwives and pharmacy workers trained in STD syndromic management (The PREVEN Network) as part of a national urban community-randomized trial of sexually transmitted infection prevention in Peru.

Methods and Findings

After a comprehensive census of physicians, midwives, and pharmacies in ten intervention and ten control cities, we introduced seminars and workshops for pharmacy workers, and continuing education for physicians and midwives in intervention cities and invited graduates to join the PREVEN Network. “Prevention Salespersons” visited pharmacies, boticas and clinicians regularly for educational support and collection of information on numbers of cases of STD syndromes seen at pharmacies and by clinicians in intervention cities. Simulated patients evaluated outcomes of training of pharmacy workers with respect to adequate STD syndrome management, recommendations for condom use and for treatment of partners. In intervention cities we trained, certified, and incorporated into the PREVEN Network the workers at 623 (80.6%) of 773 pharmacies and 701 (69.6%) of 1007 physicians and midwives in private practice. Extremely high clinician and pharmacy worker turnover, 13.4% and 44% respectively in the first year, dictated continued training of new pharmacy workers and clinicians. By the end of the intervention the Network included 792 pharmacies and 597 clinicians. Pharmacies reported more cases of STDs than did clinicians. Evaluations by simulated patients showed significant and substantial improvements in the management of STD syndromes at pharmacies in intervention cities but not in control cities.

Conclusions

Training pharmacy workers linked to a referral network of clinicians proved feasible and acceptable. High turn-over was challenging but over come.     

Improving Pharmacy Staff Knowledge and Practice on Childhood Diarrhea Management in Vietnam: Are Educational Interventions Effective?

Background

In many developing countries, private pharmacies play an important role in providing health information and services to local communities for common health issues. The aim of this study was to ascertain medium-term impact of educational interventions on knowledge and practice of pharmacy staff regarding management of childhood diarrhea in Vietnam.

Methods

This was a pre- and post-intervention study with 32 and 44 months difference from the time of the baseline survey to the conclusion of trainings and the time of the end-line survey, respectively. Interventions included in-class training for pharmacy staff, printed materials at the pharmacy, and supportive supervision. Knowledge/reported practice and actual practice of pharmacy staff were measured before and after interventions.

Results

After interventions, significant improvements (p<0.01) were observed for all indexes related to pharmacy staff''s knowledge about childhood diarrhea; for instance, 31% and 60% of surveyed staff asked about weight of the child and accompanying symptoms of childhood diarrhea, respectively, an increase from 11% and 45% at the baseline. Oral rehydration solution (ORS) was the most frequently reported product recommended (97% to 99%), but probiotics and antidiarrheals were the products most frequently prescribed at pharmacies. Public health facilities remained the preferred choice for referrals from pharmacies, but the use of private clinics was increasing. Consultations and advice provided to caregivers also improved, but considerable gaps between knowledge and actual practice of staff in real pharmacy settings remained.

Conclusions

Educational interventions were effective in improving pharmacy staff knowledge and practice regarding management of childhood diarrhea. Knowledge and actual practice of staff in real pharmacy settings did not always correlate; there is need for a stronger regulatory and law enforcement system. Interventions to improve pharmacy practice in developing countries should be focused, comprehensive, and evidence-based.     

The Potential Impact of Improving Appropriate Treatment for Fever on Malaria and Non-Malarial Febrile Illness Management in Under-5s: A Decision-Tree Modelling Approach

Background

As international funding for malaria programmes plateaus, limited resources must be rationally managed for malaria and non-malarial febrile illnesses (NMFI). Given widespread unnecessary treatment of NMFI with first-line antimalarial Artemisinin Combination Therapies (ACTs), our aim was to estimate the effect of health-systems factors on rates of appropriate treatment for fever and on use of ACTs.

Methods

A decision-tree tool was developed to investigate the impact of improving aspects of the fever care-pathway and also evaluate the impact in Tanzania of the revised WHO malaria guidelines advocating diagnostic-led management

Results

Model outputs using baseline parameters suggest 49% malaria cases attending a clinic would receive ACTs (95% Uncertainty Interval:40.6–59.2%) but that 44% (95% UI:35–54.8%) NMFI cases would also receive ACTs. Provision of 100% ACT stock predicted a 28.9% increase in malaria cases treated with ACT, but also an increase in overtreatment of NMFI, with 70% NMFI cases (95% UI:56.4–79.2%) projected to receive ACTs, and thus an overall 13% reduction (95% UI:5–21.6%) in correct management of febrile cases. Modelling increased availability or use of diagnostics had little effect on malaria management outputs, but may significantly reduce NMFI overtreatment. The model predicts the early rollout of revised WHO guidelines in Tanzania may have led to a 35% decrease (95% UI:31.2–39.8%) in NMFI overtreatment, but also a 19.5% reduction (95% UI:11–27.2%), in malaria cases receiving ACTs, due to a potential fourfold decrease in cases that were untested or tested false-negative (42.5% vs.8.9%) and so untreated.

Discussion

Modelling multi-pronged intervention strategies proved most effective to improve malaria treatment without increasing NMFI overtreatment. As malaria transmission declines, health system interventions must be guided by whether the management priority is an increase in malaria cases receiving ACTs (reducing the treatment gap), reducing ACT waste through unnecessary treatment of NMFI or expanding appropriate treatment of all febrile illness.     

Pilot Study of Essential Drug Quality in Two Major Cities in India

Background

India is an increasingly influential player in the global pharmaceutical market. Key parts of the drug regulatory system are controlled by the states, each of which applies its own standards for enforcement, not always consistent with others. A pilot study was conducted in two major cities in India, Delhi and Chennai, to explore the question/hypothesis/extent of substandard and counterfeit drugs available in the market and to discuss how the Indian state and federal governments could improve drug regulation and more importantly regulatory enforcement to combat these drugs.

Methodology/Principal Findings

Random samples of antimalarial, antibiotic, and antimycobacterial drugs were collected from pharmacies in urban and peri-urban areas of Delhi and Chennai, India. Semi-quantitative thin-layer chromatography and disintegration testing were used to measure the concentration of active ingredients against internationally acceptable standards. 12% of all samples tested from Delhi failed either one or both tests, and were substandard. 5% of all samples tested from Chennai failed either one or both tests, and were substandard. Spatial heterogeneity between pharmacies was observed, with some having more or less substandard drugs (30% and 0% respectively), as was product heterogeneity, with some drugs being more or less frequently substandard (12% and 7% respectively).

Conclusions/Significance

In a study using basic field-deployable techniques of lesser sensitivity rather than the most advanced laboratory-based techniques, the prevalence of substandard drugs in Delhi and Chennai is confirmed to be roughly in accordance with the Indian government''s current estimates. However, important spatial and product heterogeneity exists, which suggests that India''s substandard drug problem is not ubiquitous, but driven by a subset of manufacturers and pharmacies which thrive in an inadequately regulated environment. It is likely that the drug regulatory system in India needs to be improved for domestic consumption, and because India is an increasingly important exporter of drugs for both developed and developing countries. Some poor countries with high burdens of disease have weak drug regulatory systems and import many HIV/AIDS, tuberculosis and malaria drugs from India.     

Dihydroartemisinin-Piperaquine vs. Artemether-Lumefantrine for First-Line Treatment of Uncomplicated Malaria in African Children: A Cost-Effectiveness Analysis

Background

Recent multi-centre trials showed that dihydroartemisinin-piperaquine (DP) was as efficacious and safe as artemether-lumefantrine (AL) for treatment of young children with uncomplicated P. falciparum malaria across diverse transmission settings in Africa. Longitudinal follow-up of patients in these trials supported previous findings that DP had a longer post-treatment prophylactic effect than AL, reducing the risk of reinfection and conferring additional health benefits to patients, particularly in areas with moderate to high malaria transmission.

Methods

We developed a Markov model to assess the cost-effectiveness of DP versus AL for first-line treatment of uncomplicated malaria in young children from the provider perspective, taking into consideration the post-treatment prophylactic effects of the drugs as reported by a recent multi-centre trial in Africa and using the maximum manufacturer drug prices for artemisinin-based combination therapies set by the Global Fund in 2013. We estimated the price per course of treatment threshold above which DP would cease to be a cost-saving alternative to AL as a first-line antimalarial drug.

Results

First-line treatment with DP compared to AL averted 0.03 DALYs (95% CI: 0.006–0.07) and 0.001 deaths (95% CI: 0.00–0.002) and saved $0.96 (95% CI: 0.33–2.46) per child over one year. The results of the threshold analysis showed that DP remained cost-saving over AL for any DP cost below $1.23 per course of treatment.

Conclusions

DP is superior to AL from both the clinical and economic perspectives for treatment of uncomplicated P. falciparum malaria in young children. A paediatric dispersible formulation of DP is under development and should facilitate a targeted deployment of this antimalarial drug. The use of DP as first-line antimalarial drug in paediatric malaria patients in moderate to high transmission areas of Africa merits serious consideration by health policymakers.     

A Randomised Trial to Compare the Safety,Tolerability and Efficacy of Three Drug Combinations for Intermittent Preventive Treatment in Children

Background

Results from trials of intermittent preventive treatment (IPT) in infants and children have shown that IPT provides significant protection against clinical malaria. Sulfadoxine-pyrimethamine (SP) given alone or in combination with other drugs has been used for most IPT programmes. However, SP resistance is increasing in many parts of Africa. Thus, we have investigated whether SP plus AQ, SP plus piperaquine (PQ) and dihydroartemisinin (DHA) plus PQ might be equally safe and effective when used for IPT in children in an area of seasonal transmission.

Methods

During the 2007 malaria transmission season, 1008 Gambian children were individually randomized to receive SP plus amodiaquine (AQ), SP plus piperaquine (PQ) or dihydroartemisinin (DHA) plus PQ at monthly intervals on three occasions during the peak malaria transmission season. To determine the risk of side effects following drug administration, participants in each treatment group were visited at home three days after the start of each round of drug administration and a side effects questionnaire completed. To help establish whether adverse events were drug related, the same questionnaire was administered to 286 age matched control children recruited from adjacent villages. Morbidity was monitored throughout the malaria transmission season and study children were seen at the end of the malaria transmission season.

Results

All three treatment regimens showed good safety profiles. No severe adverse event related to IPT was reported. The most frequent adverse events reported were coughing, diarrhoea, vomiting, abdominal pain and loss of appetite. Cough was present in 15.2%, 15.4% and 18.7% of study subjects who received SP plus AQ, DHA plus PQ or SP plus PQ respectively, compared to 19.2% in a control group. The incidence of malaria in the DHA plus PQ, SP plus AQ and SP plus PQ groups were 0.10 cases per child year (95% CI: 0.05, 0.22), 0.06 (95% CI: 0.022, 0.16) and 0.06 (95% CI: 0.02, 0.15) respectively. The incidence of malaria in the control group was 0.79 cases per child year (0.58, 1.08).

Conclusion

All the three regimens of IPT in children were safe and highly efficacious

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00561899","term_id":"NCT00561899"}}NCT00561899     

Determinants of the cost-effectiveness of intermittent preventive treatment for malaria in infants and children

Background

Trials of intermittent preventive treatment in infants (IPTi) and children (IPTc) have shown promising results in reducing malaria episodes but with varying efficacy and cost-effectiveness. The effects of different intervention and setting characteristics are not well known. We simulate the effects of the different target age groups and delivery channels, seasonal or year-round delivery, transmission intensity, seasonality, proportions of malaria fevers treated and drug characteristics.

Methods

We use a dynamic, individual-based simulation model of Plasmodium falciparum malaria epidemiology, antimalarial drug action and case management to simulate DALYs averted and the cost per DALY averted by IPTi and IPTc. IPT cost components were estimated from economic studies alongside trials.

Results

IPTi and IPTc were predicted to be cost-effective in most of the scenarios modelled. The cost-effectiveness is driven by the impact on DALYs, particularly for IPTc, and the low costs, particularly for IPTi which uses the existing delivery strategy, EPI. Cost-effectiveness was predicted to decrease with low transmission, badly timed seasonal delivery in a seasonal setting, short-acting and more expensive drugs, high frequencies of drug resistance and high levels of treatment of malaria fevers. Seasonal delivery was more cost-effective in seasonal settings, and year-round in constant transmission settings. The difference was more pronounced for IPTc than IPTi due to the different proportions of fixed costs and also different assumed drug spacing during the transmission season. The number of DALYs averted was predicted to decrease as a target five-year age-band for IPTc was shifted from children under 5 years into older ages, except at low transmission intensities.

Conclusions

Modelling can extend the information available by predicting impact and cost-effectiveness for scenarios, for outcomes and for multiple strategies where, for practical reasons, trials cannot be carried out. Both IPTi and IPTc are generally cost-effective but could be rendered cost-ineffective by characteristics of the setting, drug or implementation.     

Fitness trade-offs in the evolution of dihydrofolate reductase and drug resistance in Plasmodium falciparum

Background

Patterns of emerging drug resistance reflect the underlying adaptive landscapes for specific drugs. In Plasmodium falciparum, the parasite that causes the most serious form of malaria, antifolate drugs inhibit the function of essential enzymes in the folate pathway. However, a handful of mutations in the gene coding for one such enzyme, dihydrofolate reductase, confer drug resistance. Understanding how evolution proceeds from drug susceptibility to drug resistance is critical if new antifolate treatments are to have sustained usefulness.

Methodology/Principal Findings

We use a transgenic yeast expression system to build on previous studies that described the adaptive landscape for the antifolate drug pyrimethamine, and we describe the most likely evolutionary trajectories for the evolution of drug resistance to the antifolate chlorcycloguanil. We find that the adaptive landscape for chlorcycloguanil is multi-peaked, not all highly resistant alleles are equally accessible by evolution, and there are both commonalities and differences in adaptive landscapes for chlorcycloguanil and pyrimethamine.

Conclusions/Significance

Our findings suggest that cross-resistance between drugs targeting the same enzyme reflect the fitness landscapes associated with each particular drug and the position of the genotype on both landscapes. The possible public health implications of these findings are discussed.