>>SOUTH SAN FRANCISCO, Calif., Jan. 28 /PRNewswire-FirstCall/ -- Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL - News) today announced the selection of R406 as its lead therapeutic compound for the treatment of rheumatoid arthritis (RA), the chronic inflammatory disease that causes pain, swelling, loss of function in the joints and the destruction of bone and cartilage for nearly 2.1 million Americans. Rigel plans to begin human safety trials with R406 in the second half of 2004.
R406 is a novel, oral syk kinase inhibitor that blocks the activation of mast cells and B cells that promote swelling and inflammatory response. Data from pre-clinical studies indicate that R406 is effective at low doses in a rodent arthritis model, and was without obvious toxicities at doses well above the effective dose.
"We are very excited to announce the selection of R406 as Rigel's lead RA compound. As we continue into human clinical trials later this year, we hope to confirm that R406 is a safe and potent disease-modifying anti-rheumatic drug (DMARD)," said Donald G. Payan, MD, Rigel's Chief Scientific Officer and Executive Vice President. "As a potentially safe, orally delivered DMARD, R406 may offer a significant advance in the treatment of rheumatoid arthritis."
Rheumatoid Arthritis: Current Treatments and Market Opportunity
Rheumatoid arthritis is a chronic inflammatory disease that affects multiple tissues, but typically produces its most pronounced symptoms in the joints. It is often progressive and debilitating, preventing people from living life symptom-free. Ultimately the chronic inflammation of joints leads to the destruction of the soft tissue and erosion of the articular surfaces of the bone.
The current treatment options for RA have significant potential side effects and other shortfalls, including gastrointestinal complications and kidney damage. RA patients receive multiple drugs depending on the extent and aggressiveness of the disease. Initially, patients with a mild-to-moderate form of the disease are offered a non-steroidal anti-inflammatory (NSAID) or a Cox-2 inhibitor. These drugs address the symptoms of RA but not the underlying progressive destruction of bone and cartilage. As the disease progresses and the patient continues to deteriorate, these drugs are then layered with more potent and potentially more toxic therapies. NSAIDs are supplemented with steroids and then a DMARD such as methotrexate, an anti-cancer agent. The other major class of DMARDs is the TNF-blocking agents such as Enbrel. These drugs block only the inflammatory mediator, TNF, and are all delivered via injection. Unfortunately, the side effects (in the case of methotrexate) and delivery (in the case of the anti-TNF agents) limit their use to late in the course of the disease when the patient is in greater distress and when the disease has already caused significant bone and cartilage damage. Rigel believes that there is a significant opportunity for an oral, safe, DMARD that can be used earlier in course of the disease preventing its progression prior to major bone and cartilage destruction.
How R406 Works:
R406 is a syk kinase inhibitor that has demonstrated inhibition of mast cell and B cell activation by both IgE and IgG, thus blocking inflammatory mediators, including TNF, various interleukins, and other mediators. R406 has been shown effective in preliminary animal models of arthritis and appears to be well tolerated in preclinical studies. Rigel believes that R406 may become a first-line DMARD with greater efficacy, safety and improved delivery and patient compliance, and thus may be used early in the course of the disease before significant bone and cartilage damage occurs.
About Rigel (www.rigel.com)
Rigel's mission is to become a source of novel, small molecule drugs to meet large, unmet medical needs. We have three initial clinical development programs: asthma/allergy, hepatitis C, and rheumatoid arthritis. We have begun clinical testing of our first two product candidates, R112 for allergic rhinitis and R803 for hepatitis C, and plan to begin clinical trials of two additional drug candidates, for the treatment of rheumatoid arthritis and asthma, by the end of 2004.<<
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