1. African medicinal plants against malaria
Dr Merlin Willcox, RITAM
(Research Initiative on Traditional Antimalarial Methods)

2. Meeting Objectives To share information
To develop a collaborative action programme for Africa-wide production and distribution of appropriate herbal antimalarials

3. The economics of malaria
2-5 billion febrile episodes a year resembling malaria
500 million cases of malaria
1.1 million deaths
90% of deaths are in African children
58% of deaths in poorest 20% of population

4. Economics of malaria (2)
Up to 75% use traditional herbal medicine as first line treatment
Adult course of ACT = $2.4, may reduce to $1
Diagnostic test = $1
Big pharma is not investing in malaria

5. What is your main objective?
To reduce malaria mortality and morbidity?
To create jobs and businesses?

6. What is your market?
Poor people in remote areas with no access to modern health care?
People who already have access to modern pharmaceuticals?
Public health programmes?
Herbal prophylactics for ex-pats?

7. What is an “appropriate” herbal antimalarial?
Standardised phytomedicine or home-grown plants?
Cheaper than ACTs?
Parasite clearance or adequate clinical response?
Efficacy or cost-effectiveness?
Depends on context….

8. Types of R&D: Different products, endpoints & methodologies
Bioprospecting for active molecules: new leads for conventional drug development
Phytomedicines: standardised herbal extracts.
Traditional medicine: prepared according to traditional formulations

9. The competitive advantage of herbal antimalarials
Affordable
Available
Sustainable
Reach the parts that modern drugs don’t reach…

10. Ways of using plants against malaria
Insect repellents
Vector Control
Prophylaxis
Treatment

11. The limitations of traditional medicine
There is little clinical data on safety and efficacy
Content of active compounds in plants is variable
There is no consensus on what plants, preparations and dosages to use
These are all remediable, through research…

12. RITAM Research Initiative on Traditional Anti-Malarial Methods
Founded in 1999 by GIFTS of Health, with support from TDR, Rockerfeller

14. Specialist Groups Policy, Advocacy and Funding Preclinical
Networking, publications, funding, ethics, intellectual property rights
Preclinical
Database, guidelines
Clinical Development
Database, systematic reviews, guidelines
Insect repellence and vector control
Artemisia annua Task Force
Overview of literature
Clinical trials planned

15. The bottom line Herbal insect repellents: some evidence
Herbal insecticides: some evidence
Herbal treatments: controversial, some clinical evidence
Herbal prophylactics: NO clinical evidence

16. Chicken or egg? “Show us the evidence that it works”
Who will pay to generate the evidence?

17. Herbal treatments
No herbal treatments have yet been described to be as efficacious as ACTs for parasite clearance
Several herbal treatments could potentially be more cost-effective than ACTs in certain contexts

18. Where could herbal antimalarials be more cost-effective?
Home management
Presumptive malaria
Semi-immune patients (Adults, children > 5 years old)

19. When is it unethical to recommend herbal antimalarials?
[on current evidence]
Non-immune patients
Children aged <5
Pregnant women
? If a proven treatment is locally available and affordable to the patient?

20. The Artemisia annua debate
Jansen, 2006: “I believe that the herbal tea approach to artemisinin as a therapy for malaria is totally misleading and should be forgotten as quickly as possible”.
Anamed: promoting A. annua cultivation and use as a tea.
RITAM response: Need more research

21. Approaches to A. annua
Grow the plant as a cash crop, to sell to pharmaceutical companies, which will make ACTs
Grow the plant for local distribution as tea bags
Grow the plant in village “green pharmacies” where no other healthcare is available.

22. Problems with A. annua tea
High level of recrudescence at doses tested
Optimal method of preparation and dosage not yet defined
Variability in artemisinin content

23. Potential of A. annua tea
Cheaper than ACTs
Could it be more cost-effective in certain situations, e.g. for home treatment of malaria?
Could it be more effective if combined with other herbal antimalarials?

24. Prophylaxis Many herbal prophylactic preparations are used
Almost none have been investigated
Some Hausa tribes have lower than expected incidence of malaria (Etkin & Ross, 1991)
In the malaria season, they eat plants with antimalarial properties

25. Neem as a repellent
Neem oil on cardboard mats is as effective as synthetic repellents
Costs $0.50 per room per year (cf. $25 for synthetic repellents)
Also effective topically (2% in coconut oil) for 12 hours
Neem oil is larvicidal (LC50 = 3-8ppm)

26. Phytolacca dodecandra
Widespread tropical plant
Crushed, powdered berries used as soap and as pesticide
Effective at killing schistosomiasis transmitting snails
Effective at killing mosquito larvae

28. Possible roles for medicinal plants
Vector control and repellence
Prophylaxis
Treatment, especially:
Presumptive malaria
Home management
Adults and children >5

29. Conclusions Herbal antimalarials have huge potential
More research IS needed (esp clinical and public health)
But who will pay for it?
Need to go beyond laboratory studies in order to deliver a health impact.