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Daily report - Tuesday 3 November 2009

Source: TropIKA.net editorial team

The key message of the second day’s plenary session was the need for evidence-based research to influence malaria policy.

Halima Mwenesi from the Academy of Educational Development gave a historical perspective on advocacy. For several decades, poor guidelines on the development of policy and a lack of a strong push to advocacy for malaria meant that results in controlling the disease were patchy.

There is now cause for guarded optimism, Mwenesi said, with the creation of the Global Malaria Action Plan. But there are challenges ahead: sporadic commitment from leaders because of a changing political landscape; inflexible funding mechanisms; and no mechanisms for holding donors, partners and other stakeholders accountable for their commitment.

A strong advocacy target has been to build robust health systems, a problem that many African countries are aware they need to fix. Hassan Mshinda from the Tanzania Commission for Science and Technology discussed the way that some interventions lose traction in health systems. However efficacious an intervention, there are various limiting factors such as poor diagnostics or provider non-compliance. This means that the ultimate effectiveness could be 50% that of the efficacy of the intervention in clinical trials. Mshinda described this as “driving with the brakes on”.

AMANET’s Wen Kilama spelled out several roadblocks to boosting Africa’s ethics systems. The first is that African regulatory bodies are insufficiently prepared for regulation enforcement; there are high costs associated with regulatory review; and there may not be any regulations in place for controversial techniques like genetic modification of mosquitoes.

Brian Greenwood talked about treatment for control. The knowledge that malaria treatment can also be protective against infection for some time in the future changes the types of drugs that scientists research. This knowledge has come from a deeper understanding of the pharmacokinetics of the drugs – researchers are moving towards using "long-acting" drugs because they remain in the body.

Charles Mgone at the European & Developing Countries Clinical Trials Partnership (EDTCP) talked of a long-term responsibility to building research capacity in malaria. That capacity building, he said, should be based on a needs assessment.

Symposium 12 discussed exciting new research in pregnancy-associated malaria. Researchers have developed mice models of placental malaria that mimic placental malaria in human beings. Although a first pregnancy following exposure to malaria infection is associated with recrudescence, multiple pregnancies are associated with increased immunity. In neonates, placental malaria was shown to suppress innate and adaptive immune responses, rendering offspring more susceptible to infection. Cord blood cytokine (TMF) levels predict the time to first malaria episode and the frequency of episodes in early childhood. A high cytokine level is also associated with low risk of severe and moderate severe malaria in neonates.

Early-stage drug discovery was the topic of Symposium 13, hosted by ANTIMAL, an integrated project comprising leading groups of researchers with expertise in malaria biology, chemotherapy and drug development. Only by building a modern technology platform capable of tapping into modern drug discovery paradigm can the African research community exploit the bounty of natural products unique to the continent for its therapeutic potential.

Vaccines were the theme of Session 14, where discussion revolved around GMZ2, a combination of GLURP and MSP3 vaccine candidates, which elicit a stronger immune response than each individual vaccine. GMZ2 was shown to be safe and effective in German and Gabonese malaria-naive adults and Gabonese children; any adverse effects disappeared by day 3 after inoculation. Efforts are under way to start phase IIb trials in children aged 1-5 years from the Gambia, Uganda, Burkina Faso, and Gabon by early next year after the complete analysis of the phase I trials. Though this vaccine is promising, we still need more vaccine candidates to be developed.  

Symposium 15, hosted by Novartis – Coartem, discussed strategies of malaria management, treatment, and patient benefit from community development. Strategies need to be scaled up through community-directed interventions such as home-based management of malaria. Community workers need the support and partnership of the public and private sector. Several studies presented data on the safety of Coartem in pregnancy; they showed that the drug is safe in the second and third trimesters of pregnancy and, to some extent, the first trimester.

Five years after ACT became the WHO-recommended frontline treatment for malaria, access to the drugs remains woefully out-of-reach for the poorest patients. That was the news in Symposium 16, as reported by PSI, which just unveiled data from a new study of availability, volume, price and use of antimalarials in 7 malaria-endemic countries (6 in sub-Saharan African and Cambodia). The study reported that ACTs currently make up between 5 and 15% of the total volume of antimalarials on the market; that ineffective monotherapies permeate private sector markets; and that availability of effective artemisinin combination therapy is as low as 20% in public sector health facilities. The study also included a supply chain analysis and an analysis of the determinants of prompt and effective treatment of febrile illness in children.

That was followed by Symposium 18, also hosted by MMV-PSI, on improving access to ACTs. Strategic changes in the case management of malaria should include: a treatment policy change to incorporate anti-gametocytic treatments; 100% parasitological confirmation of cases; and immediate notification of cases, among others. There is no one size fits all solution to the dearth of novel therapies for malaria. MMV priorities include bringing fixed-dose ACTs to the market; development of the next generation of drugs for the radical cure of p. vivax malaria; and increasing the supply of GMP-grade parenteral artesunate for the treatment of severe malaria.

Symposium 19 was hosted by the Worldwide Antimalarial Resistance Network (WWARN), an information resource aimed at addressing the problem of lack of quality data on markers of antimalarial drug resistance. Markers include molecular markers, drug blood levels and data from clinical areas. WWARN’s objective is to provide researchers with standardized protocols; secure storage of data; a forum for knowledge sharing; and analytic tools to generate evidence for policymakers.

Surveillance is necessary to improve vector control and estimate intervention impact, said a panel of experts on M&E vector control in symposium 20. The most efficient, cost-effective, and sustainable programme would be one that responds to the way the epidemiology of the local disease changes. Speakers discussed Malaria Decision Support Systems - an innovative data management system that supports decision-making in an operational environment.   

Symposium 23, hosted by the Malaria in Pregnancy Consortium, started from the fact that many pregnancies are at risk of malaria in endemic areas. Pharmacokinetic studies are crucial for pregnant women to establish whether high enough concentrations of treatment drugs are absorbed. Such studies also measure the half-life of the drug to determine whether the patient is likely to suffer re-infection after the first treatment. Intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine works well to reduce neonatal and infant mortality.

Highlights from scientific session 13 on the assessment of malaria burden, included two recent studies in Senegal and Kenya that indicate decreasing susceptibility to malaria infection with increasing age. A study in Uganda of trimethoprin-sulfamethoxazole (TS) prophylaxis has demonstrated 40% protection against malaria infection in HIV-positive children. And a study of treatment failure with amodiaquine-sulfadoxine/pyrimethamine combination in Uganda showed that failure is associated with decreased host immunity to malaria infection rather than increased resistance to sulfadoxine/pyrimethamine, as was expected.

Scientific session 14 focused on health systems research, citing the value of community health workers in scaling up delivery of IPTp. A study in Uganda has shown that, with training, community members (traditional birth attendants, drug-shop vendors, adolescent peer mobilisers and community reproductive health workers) can provide IPTp using SP to pregnant women and achieve higher coverage and birth outcomes than public health centers. The use of Rapid Diagnostic Tests before the administration of artemisinin-based combination treatment is less costly than presumptive treatment of malaria. The nationwide delivery of ITNs through public-private partnerships approach in Tanzania is acceptable to all stakeholders, including the National Malaria Programme, district health management teams, health workers, community members and partner NGOs. According to nurses of antenatal clinics however, the system adds considerably to their workload.

Scientific Session 15 was devoted to treatment and control as well. Community health workers should be part of the strategy to scale up the use of and promote access to Coartem. While this approach has demonstrated an ability to reduce morbidity, there are a number of challenges associated with it, including providing proper incentives for community health workers; erratic funding and faulty supply chains; and poor storage conditions. A study in Tanzania has established a replicable model for post-marketing surveillance of home-based management of Coartem use.

Treatment and control of severe malaria was the focus of Scientific Session 16.

A new study of children with severe malaria reports that an increased frequency of hypoglycemia is associated with a new quinine regimen of 20mg/kg loading dose; the older regimen was 15mg/kg loading dose. Using artemither lumefantrine for the treatment of uncomplicated malaria has been found to be more effective than using oral quinine owing to reduced treatment failure and better adherence, although similar adverse events were reported. A study in Kabale district, Uganda (an area of low malaria transmission) showed high haemoglobin levels in pregnant women using IPTp-SP and ITNs compared with those using only IPTp or ITNs. No difference was observed in the birth weights of their children.

Scientific Session 17, a late breaker, looked at Africa’s changing malaria burden; there is a general decline in cases and mortality across low and moderate transmission regions of Africa. This has been attributed to increased investments in malaria interventions, for example ACTs, insecticide-treated bednets, and indoor spraying. This doesn’t mean that we should be complacent because malaria burden is rising in the highlands of Kenya, Uganda, Tanzania, and Rwanda. Meanwhile, researchers have been classifying the sickle-cell beta-globin haplotype, which confers protection against malaria. The Benin haplotype (a haplotype is a set of closely linked genetic markers which tend to be inherited) has been found to be the most prevalent and diverse in Africa, accounting for 50% of all beta-globin haplotypes in Benin, Ghana, Kenya, Malawi, and Nigeria. Intermittent preventive treatment in pregnancy (IPTp) with at least one dose of sulfadoxine-pyrimethamine (SP) reduces the risk of malaria in the first 6 months of life in Ghanaian children.

Research capacity strengthening was the theme of scientific session 18, where particular emphasis was placed on capacity strengthening in clinical trials and computational chemistry. Bridging gaps between donors, government, and researchers is critical to the effort. Significant challenges arise in post-conflict settings like Liberia, however, where recruiting and retaining competent professionals for voluntary service on the institutional review board remains an uphill battle.

Scientific session 19 focused on health research ethics. Ethics are often given a low priority despite the fact that they underpin every clinical trial. Ethics board members are volunteers, however, and balance their regular job with ethics reviews – often with very few resources. The volume of research is increasing continuously, and trial protocols are becoming more complicated so ethicists need to be expert enough to deal with this. In Africa, ethics review members are rarely given training nor do they follow standard operating procedures. This lack of experience can mean that trials are delayed for several months.

Controversy 2 tackled the difficult subject of malaria vaccines, and two speakers debated whether there is any point in pouring money into developing one. Speaking in favour, was Stephen Hoffman of Sanaria. Hoffman acknowledged that the challenges include a high cost, safety, stability and the non-availability of good clinical development plan, but thinks that pushing for a vaccine is worthwhile, nevertheless. He thinks that a hybrid rather than single vaccine will be the most effective.

Babatunde Imoukhuede of the European Malaria Vaccine Initiative doesn't agree, and thinks that the hurdles are too great to overcome. Vaccines that require refrigeration have been notoriously hard to roll out in developing countries because of unreliable electricity supplies and transport difficulties. With Hoffman, meanwhile, optimism is running high. He called for the first set of vaccines to be available in the market by 2015.

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