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Toll-Like Receptors

Toll-Like Receptors, or TLRs, are a relatively new scientific discovery, though their origins date back hundreds of millions of years, devised as a way to protect organisms against pathogens such as viruses and bacteria. This defense mechanism has proven so effective that it is an integral part of the human immune system today and a promising target for innovative new medicines.

Less than a decade ago the first human TLR was cloned. Now scientists have discovered 10 TLRs in humans, each recognizing generic molecular patterns associated with a variety of invading pathogens.

Viral Infections
Certain TLRs, for example, are responsible for fighting bacterial and fungal infections; others respond specifically to viral infections.

Unlike adaptive immunity, which enables the immune system to remember and fight infections that it has encountered before, innate immunity has the ability to recognize foreign invaders upon their very first meeting. This function is regulated by TLRs, a family of proteins that serve as the body's first line of defense.

Once a TLR recognizes a particular pathogen, it launches a dual assault. First, it triggers the body's innate immunity, triggering an inflammatory response to fight the invader. Then it alerts and educates the body's adaptive immune system so that it will recognize the pathogen in the future. If TLRs fail, the body is left vulnerable to infection.

At Anadys, we believe that the clinical proof-of-concept in fighting hepatitis C that we have already established with isatoribine, combined with our portfolio of clinical and preclinical candidates and intellectual property strategy, positions us at the forefront of this creative effort to combat viral diseases.

Cancer
In late 2005, Anadys selected ANA773, a novel Toll-Like Receptor-7 (TLR-7) oral prodrug, for pre-clinical development. ANA773, which is wholly owned by Anadys and falls outside any existing collaboration, is being developed as an oral therapy for the treatment of certain cancers.

Agonists of TLR-7 have significant potential for treating a variety of diseases. Anadys believes ANA773 may be effective in certain types of cancer. The selection of this compound for clinical development marks an exciting new step in our proprietary TLR-7 drug discovery and delivery platform, and underscores Anadys' creativity and productivity in advancing novel compounds into pre-clinical development and the clinic.

ANA773 is currently in preclinical development.