Avera Pharmaceuticals

Proof of concept evaluation in IBS and OAB were initiated in Q2 2006.

Following acquisition of AV608 from Novartis, Avera reformulated the compound to increase both unit dose strength and total plasma exposure after oral administration. This novel formulation was carried forward into Phase 1 single and multiple dose studies. There were no dose-limiting toxicities and the drug was well tolerated. This formulation has been deployed for clinical proof of concept evaluation in Irritable Bowel Syndrome (IBS) and Overactive Bladder (OAB).

Prior to acquisition by Avera, Novartis completed Phase 1 and Phase 2 clinical studies in a total of 1,739 drug-exposed subjects and patients and thus created a large human safety database.

AV608 for IBS
It is known that the human intestinal mucosa expresses NK-1 receptors. These receptors are also found in the smooth muscle, arterioles, venules and cells associated with lymph nodules and co-localized with substance P, which is found throughout the gastrointestinal tract. Nerve fibers, including sensory fibers, come into close contact with mast cells, which also express NK-1 receptors. Furthermore, approximately 80% of visceral sensory afferents in the gut express substance P, and it is known that NK-1 receptors in the spinal cord mediate visceral hyperalgesia. Tachykinins are potent secretagogues at the small and large intestinal mucosa in several animal models as well as in the human colon, where there is a direct NK-1 receptor mediated response. Perhaps most important with respect to IBS is the observation that stimulation of sensory fibers or mast cells in the human intestinal tract causes the release of substance P and a consequent increase in epithelial ion transport through the activation of NK-1 receptors. The response to colorectal distension has often been used as a proxy for IBS. In this model, colorectal distension increases abdominal flinching, which is an indicator of pain. This procedure also activates a rectocolonic inhibitory reflex characterized by a decrease in colonic pressure and an increase in fluid transport. Several authors have now observed that NK-1 receptors mediate this rectocolonic inhibitory reflex. Decreased colonic pressure is related to increased colonic transit and these findings are therefore consistent with reports that stress increases intestinal transit, an effect blocked by NK-1 receptor antagonists.

AV608 for Overactive Bladder
Overactive bladder is a common and distressing condition that has a profound effect on the daily living of affected individuals. This common cause of urinary incontinence describes a cluster of symptoms typified by urinary urgency, frequency, and urge urinary incontinence. Whereas the currently available anticholinergic drugs used to treat overactive bladder act on efferent nerves to counteract overactive bladder, essentially after it occurs, NK-1 antagonists appear to have promising therapeutic potential in their ability to affect the afferent nerves that modulate bladder contraction. A key potential advantage of NK-1 antagonists is that there may be essentially no decrement of detrusor contractility and no urinary retention risk, as is seen with current anticholinergic agents. This is because NK-1 antagonists inhibit sensory afferent nerves but not efferent nerves, which are important for normal and complete voiding of urine. Furthermore, NK-1 antagonists have a more favorable tolerability profile than observed with anticholinergic medications.