Rigel Commences Phase 2 Trial of R788 in Peripheral T-Cell...( Preclinical Rationale for Clinical Tr...),Health

Preclinical Rationale for Clinical Trial Presented at USCAP Meeting

SOUTH SAN FRANCISCO, Calif., March 13 /PRNewswire-FirstCall/ -- Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL) today announced the enrollment of the first patient in a Phase 2, multi-center clinical trial of R788 (fostamatinib disodium) in patients with refractory or relapsed peripheral T-cell lymphoma (PTCL). The clinical trial's primary objective is to assess the efficacy of R788, an orally bio-available Syk kinase inhibitor, in patients suffering from this subset of non-Hodgkin's lymphoma that originates in the patient's T-cells. Prior studies have suggested increased expression of Syk at the cellular level in many of these patients with PTCL.

"Since we have seen that R788 shows clinical therapeutic benefit in certain types of B-cell lymphomas and that Syk kinase appears to play an important role in certain PTCLs, we believe that R788 may offer new hope to the 12-15% of non-Hodgkin's lymphoma patients with the T-cell variety," said Elliott Grossbard, M.D., executive vice president and chief medical officer of Rigel.

In general, patients with PTCL have a poorer prognosis and fewer treatment options than B-cell lymphoma patients. The standard treatment regimen for PTCL, known as CHOP, fails to provide adequate or durable responses in many patients. CHOP is a treatment regimen consisting of cyclophosphamide, hydroxydoxorubicin, vincristine (oncovin) and prednisone.

Pre-clinical Results Presented at USCAP Meeting

In a related matter, results of a pre-clinical study of R788 were presented in an oral session of the United States and Canadian Academy of Pathology annual meeting in Boston this week on March 9, 2009. The presentation, entitled, "An Orally Available Syk Tyrosine Kinase Inhibitor Induces Apoptosis
'/>"/>