Venom as drugs
Venoms, ancestral therapies
- Traditional Chinese and Indian medicine used Cobra venoms to treat arthritis for thousands of years
- The medicinal use of bee venom dates back to ancient Egypt – Hyppocrates used bee venom to treat joint pain and arthritis
Modern discovery and first blockbusters
- In 1888 a clinical publication described bee venom properties to treat rheumatism
- In 1900, John Henry Clarke’s affirmed animal venoms have the potential to alleviate many ills such as angina pectoris, asthma, hay-fever, headache …
- In 1960, Hugh Alistair Reid discovered that the venom of the Malayan pit viper prevents blood clotting. Subsequently, a protein called Ancrod was shown to prevent blood clots to form.
- In 1975, the Brazilian pit viper’s venom led to the development of the first oral drug for hypertension, captopril. The ACE inhibitor class of drugs pioneered by captopril now treats millions of patients worldwide, with multibillion-dollar sales.
Other derivative drugs from animal venoms were then approved and are on the market such as Aggrastat, Integrilin and more recently Byetta and Prialt.
Contemporary use of venoms in drug discovery and development
Recent HTS screening technologies combined with proteomic analytical capabilities facilitate the use of animal venoms as discovery sources of new lead compounds.
Dozens of compounds are currently in development to treat pain, autoimmune disorders, cancers, heart diseases…
Animal venom: a vast natural library of constrained peptides
Animal venom originating from over 170.000 species are complex molecular mixtures each containing several hundred peptide toxins; representing a natural reservoir of over 40 million biologically active molecules. These compounds demonstrate invaluable pharmacological properties and are highly stable thanks to their unusual constrained structures that usually involves complex disulfide-bridge patterns.
This natural resource is largely under-exploited and, less than 2000 peptide toxins have currently been identified and partially characterized. In spite of this small number, these compounds have led to the clinical exploitation of seven drugs (Ziconotide, Exenatide, Captopril, Eptifibatide, Tirofiban, Batroxobin) and dozens of other natural peptides are currently in development. It is therefore reasonable to claim that, compared to classical chemical libraries used in drug discovery programs, venoms have a far greater success rate as a source of innovative drugs.
Venom peptide benefits
- Target ion channels, GPCRs, integrins …
- Highly selective
- Highly soluble
- Highly stable thanks to disulfide bridges
- Small size
- Cardiology: long QT syndrome, arrhythmia
- Immunology: autoimmunity
- Neurology: pain, epilepsy
- Oncology: glioma, …
- Metabolism: diabetes
- Unexpected applications such as fertility, etc…
Targeted mini-libraries of pre-optimized compounds
Animal venoms have been developed by nature to allow several species to defend themselves against predators or immobilize their prey. Most common strategies rely on rapidly paralyzing prey by blocking the cardiac, respiratory, and/or nervous systems. Conversely, predators are dettered from approaching their prey by painfull sensations inflicted by the latter. At a molecular level, the targeted physiological systems are blocked or stimulated by peptide toxins which, once injected in the veinous system, pin-point, though not exclusively, important cell membrane receptors such as ion channels and G protein coupled receptors.
Millions of years of constant evolution have led to the optimization of the properties of these peptides making them more potent, more selective, poorly immunogenic, and improved in terms of pharmacokinetic properties. The resulting advantage is that they induce long-term and potent effects on enemies and prey alike. This optimization process has been enabled by the diversification of peptide sequences (mainly by gene duplication) and an upscaling of the complexity of peptide structures through implementation of disulfide bridges and fold diversification, leading to a wide diversity of chemical structures and an important resistance to proteases.
Venoms constitute highly enriched mini-libraries of pre-optimized peptides that preferentially target ion channels, GPCRs and several other membrane receptors.