Rigel Pharmaceuticals Inc (RIGL)

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3rd day of movement. News today.

Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL) announced that the American Journal of Physiology has published recent research results with its orally-bioavailable AMPK activator, R118. The publication, entitled "Exercise performance and peripheral vascular insufficiency improve with AMPK activation ", provides strong preclinical evidence that R118 may be useful in treating peripheral artery disease (PAD), a chronic and progressive vascular disease effecting nearly 5% of the population over the age of 50, and related metabolic disorders. This publication extends work from a previous Rigel publication on the mechanism and impact of AMPK activation. The Company also announced that it has commenced Phase 1 clinical studies with R118 as a potential treatment for Intermittent Claudication (IC), a painful and debilitating outcome of PAD.

"There is considerable excitement about the potential for AMPK activation to restore both mobility and endurance to people suffering with the effects of poor blood circulation as a result of chronic vascular or metabolic diseases. The market potential for a new treatment in these indications is large," said James M. Gower, chairman and chief executive officer of Rigel.

"Rigel has been at the forefront of AMPK research and we are proud to be taking the R118 program forward into clinical studies."

Rigel R118 and AMPK Activation Mechanism Publications

The latest AMPK publication in the American Journal of Physiology, Heart and Circulatory Physiology, http://ajpheart.physiology.org/content/early/2014/02/19/ajpheart.00839.2013, features Rigel's extensive research profiling R118 in a novel murine model designed to mimic the physiological conditions of people with chronic PAD. Various measurements were taken to record both the cellular-level functionality of R118 in the muscles' vasculature and the exercise performance of the group receiving R118 treatments compared to the untreated, or those treated with a positive control. In the study, the group treated with R118 showed functional performance benefits, including the ability to run faster and longer, as well as notable improvements in cellular energy efficiencies and small blood vessel perfusion.

In an earlier publication, "AMPK Activation through Mitochondrial Regulation Results in Increased Substrate Oxidation and Improved Metabolic Parameters in Models of Diabetes", published on December 5, 2013 in PLoS One (8[12]:e81870), http://dx.plos.org/10.1371/journal.pone.0081870, Rigel researchers presented information on the mechanisms by which molecules like R118 activate AMPK and the resulting impact on mitochondrial function, nutrient metabolism, and glucose and lipid homeostasis.

AMPK Activation

AMPK (adenosine monophosphate-activated kinase) is a master regulatory protein that has been shown to play a role in how effectively cells use energy and respond to biochemical changes brought on by exercise and cellular stress. The skeletal muscles of people with PAD display a number of biochemical characteristics that are linked to poor exercise performance or insufficient small blood vessel perfusion. This results in IC symptoms, which can limit their lifestyles and contribute to disease progression. Research on AMPK activation indicates that this treatment approach may have significant clinical benefit for people with PAD, as well as for patients with metabolic disorders, such as diabetes.

R118 Clinical Development

Rigel has initiated a Phase 1 clinical study of R118 in normal healthy volunteers with a goal of subsequently entering into a Phase 2 proof-of-concept trial in intermittent claudication.