What’s Your Poison?
Could compounds derived from tick saliva make effective pharmaceuticals?
For many people, the mere sight of a creepy-crawly can evoke a fight-or-flight – or perhaps a shoe or scream – response. Scientists think we’ve evolved an innate fear of spiders because they presented a great danger during the evolution of our species. And the same goes for scorpions, snakes, ants and other potentially venomous creatures. Ironically, however, a number of dangerous biological poisons make excellent medicines. We spoke with Gur Roshwalb, CEO of Akari Therapeutics, who told us how therapeutics are being developed from venomous tick saliva.
Why are venoms good candidates for treatments?
One of the most fruitful places to look for human medicines is the vast array of poisons and venoms that organisms have evolved over the course of millions of years to ward off predators or to attack prey. The bodily mechanisms that venoms derail often turn out to be the same ones doctors need to manipulate in order to treat disease. These naturally occurring substances already do what human-made drugs do: target and modulate key molecules in cells. By controlling the dosage or slightly altering the chemical composition, scientists can turn toxins into treatments.
Why tick saliva?
A tick takes a blood meal from its host for anywhere from 12 hours to two weeks, depending on the tick. To stay on the host for that long, we believed the tick had to be suppressing the local immune system of the host. Our CSO, Miles Nunn, was tasked with discovering the presumed complement inhibitor – which he did in the saliva of the Ornithodoros moubata tick.
Mile’s discovery was important because it is known that complement inhibition can also play a key role in addressing a range of immune disorders. We have derived a new inhibitor of the complement protein C5, called Coversin. This is our company’s lead product. C5 modulates the host immune system to allow the parasite to feed without alerting the host to its presence or provoking an immune response. Coversin acts on complement component-C5, preventing release of C5a and formation of C5b – 9 (also known as the membrane attack complex or MAC).
How has the compound performed in the clinic?
We have demonstrated clinically meaningful symptomatic improvement in an eculizumab-resistant, paroxysmal nocturnal hemoglobinuria patient self-administering Coversin for more than a year. The patient continues to demonstrate complete complement inhibition without any change in dose, neutralizing antibodies or injection site reactions. Paroxysmal nocturnal hemoglobinuria is a rare, and often fatal, blood disorder with no current treatment.
Over the course of my Biomedical Sciences degree it dawned on me that my goal of becoming a scientist didn’t quite mesh with my lack of affinity for lab work. Thinking on my decision to pursue biology rather than English at age 15 – despite an aptitude for the latter – I realized that science writing was a way to combine what I loved with what I was good at.
From there I set out to gather as much freelancing experience as I could, spending 2 years developing scientific content for International Innovation, before completing an MSc in Science Communication. After gaining invaluable experience in supporting the communications efforts of CERN and IN-PART, I joined Texere – where I am focused on producing consistently engaging, cutting-edge and innovative content for our specialist audiences around the world.
