- by Alison Booth

Combating growing insecticide resistance

Image of am child sleeping under a mosqutio net, to stay protected from 'dengue mosquitoes'.

Image courtesy of IVCC

Insecticide resistance has reached a tipping point. “Mosquitoes have developed resistance to all the major classes of insecticides,” says Dr. Sarah Rees, Portfolio Manager at the Innovation Vector Control Consortium (IVCC). “This makes the development of new insecticides for vector control increasingly urgent.”

But getting new insecticides to market can take a great deal of time and money. And even when new products arrive, encouraging organizations to adopt them and people to use them can be challenging.

Image of IVCC logo

Breaking down the barriers to insecticide innovation

Established in 2005, the IVCC public-private product development partnership is helping to bring new classes of insecticides to market more rapidly. A not-for-profit company, IVCC works with multiple stakeholders to remove the barriers to innovation in the vector control.

As a registered charity, IVCC’s work depends on donations. Major donors include The Bill & Melinda Gates Foundation, UKAID, USAID and the Swiss Agency for Development and Cooperation. IVCC uses those funds to develop new insecticides, in agreement with funders.

“Our role is to ensure funders’ money is spent appropriately and not wasted on something that isn’t likely to work or isn’t going to be safe,” says Dr. Rees.

Scientists from IVCC look for new ways to contol mosquito populations to combat insecticide resistance.

Image courtesy of IVCC

At the same time, IVCC is also challenging stakeholders on accelerating the development of new products. It wants to see the same principles and urgency seen during the Ebola crisis applied to combatting other diseases.

Partnerships crucial to success

IVCC’s agro-chemical partners are critical to the development of new insecticides. They hold the specialized infrastructure, resources and expertise needed to develop and then manufacture these products.

The partners begin the development process, which involves screening millions of potential compounds for likely candidates. These are then examined further for potency, safety and cost efficacy. With safety regulations around pesticides very significant, IVCC must ensure early on that it’s not investing in a product that isn’t going to be safe. At the same time, it must also ensure the product won’t require a complex manufacturing process or expensive ingredients.

After numerous iterations, IVCC and its partners settle on a particular chemistry that looks promising. Dr. Rees explains the next steps: “We take the chemical out to the field and test it for its effectiveness against wild mosquitoes and also for resistance.”

If it’s still looking promising, the very expensive parts of the process begin: safety studies and scaling up for manufacture. “We have to look long and hard at these potential products to ensure they’re really going make it before we decide to invest,” adds Dr. Rees.

A commercially viable product

IVCC mostly works with big companies, for product development at least. It’s very important that the insecticide manufacturers stay on board throughout the process and for years to come. They have the expertise needed not only to develop and manufacture the products; but also to sustain them in the marketplace when they come up for safety reviews, for instance.

“The partners are mainly commercial organizations,” explains Dr. Rees. “It’s a difficult and volatile market and we’re asking them to focus their world-class experts on our challenges. Putting forward a good business case for them to put time and effort into the development of these insecticides is crucial.”

The agrochemical companies need to be confident that governments and charities will adopt their products and that people will use them. This means they must ensure these innovations deliver better value than, and are at least as easy to use as, their predecessors.

“You’ve got to think about people’s lifestyles and how you can give them protection, in a way that makes them want to take up that protection.”

Novel chemistry faces tough competition

But many of the existing products, which often don’t work well, are old and generic. Their price has dropped over the years. To be commercially attractive, any new products will need to be able to command a higher price than these in the marketplace.

“We’ll be producing better quality products that break the resistance,” says Dr. Rees. “But procurement agencies are tempted to make decisions guided by lower prices even when the products are less effective. One of our challenges will be getting a common understanding about value for money.”

Dr. Rees also emphasizes the importance of creating a product that people actually want to adopt: “You’ve got to think about people’s lifestyles and how you can give them protection, in a way that makes them want to take up that protection.”

Find out what we could do better when it comes to vector control

IVCC works with smaller organizations too. “We want to partner with people who have the right expertise and resources for different parts of our process,” adds Dr. Rees. “A large commercial agrochemical manufacturer might, for example, partner with a smaller organization that could deliver these insecticides in different ways.”

Malaria and dengue: common challenges

IVCC is currently developing compounds that are active against resistant strains of the Anopheles genus of mosquito, which transmits malaria. Anopheline mosquitoes tend to be active at night when people are at home sleeping, so chemicals need to work well as an indoor residual spray or on a bed net. However, IVCC’s industry partners begin their development processes by first screening against an easy-to-culture mosquito such as Aedes, which is a vector of dengue, Zika, and other neglected tropical diseases.

Image of a scientists work on new forms of mosquito control.

Image courtesy of IVCC

“We know that the chemicals might also be useful against Aedes,” says Dr. Rees. “Our safety and manufacturing processes would be exactly the same for Aedes, but Aedes mosquitos tend to be more active in the daytime when people are out of their homes and so the challenge is how to protect people against day flying, outdoor living mosquitos. We’d need to explore whether you could put the chemical into a fogging, or similar, device.”

A sustainable solution

Nevertheless, the resistance challenge applies equally to malaria and dengue. “It’s really important that we bring new products to market in a way that’s sustainable,” says Dr. Rees. “We have to be careful that we don’t overuse them otherwise resistance will build up and we’ll be left with nothing again.”

Insecticides are a vital ingredient in the fight against vector-borne diseases such as malaria and dengue. Integrated vector management will be crucial to ensuring they are not overused and, once on the market, continue to provide protection for many years to come.

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