Pharmacyclics Announces Preclinical Results Supporting Development of Its Novel Btk Inhibitor in Immune Mediate...( SAN DIEGO and SUNNYVALE Calif. Ap...),Health

SAN DIEGO and SUNNYVALE, Calif., April 14 /PRNewswire-FirstCall/ -- Pharmacyclics, Inc. (Nasdaq: PCYC) today presented results from its preclinical program evaluating PCI-32765, an orally available, selective inhibitor of Bruton's tyrosine kinase, or Btk, in B-cell receptor (BCR) modulated diseases such as lymphomas and autoimmune diseases. The data were presented during the Annual Meeting of the American Association for Cancer Research (AACR) being held this week in San Diego, CA.

Researchers conducted studies with PCI-32765 examining the downstream signaling events in the BCR signal transduction pathways. In vitro drug treatment of B-cell lymphomas blocked BCR mediated signaling and in vivo drug treatment of lymphoma-bearing animal models resulted in inhibition of tumor growth. Normal human B-cell activation was also shown to be inhibited by drug treatment in vitro. PCI-32765 also showed significant activity in animal models of arthritis.

"These studies highlight the importance of Btk in immune mediated diseases," said Joseph J. Buggy, Ph.D., vice president of research for Pharmacyclics. "Further, these data support our ongoing IND-enabling studies for PCI-32765, and our plans for an anticipated clinical trial later this year."

B-cells are a type of white blood cell that normally play a key role in the body's immune response. However, when B-cells are overactive, the immune system produces inflammatory cells and antibodies that begin to attack the body's own tissue, leading to autoimmune diseases such as rheumatoid arthritis. Most lymphomas are caused by uncontrolled growth of B-cells. Btk is an enzyme that plays a crucial role in B-cell activation and inhibition of its function may be useful in the treatment of imm
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