AstraZeneca's fostamatinib safe, but not effective, in RA patients unresponsive to biologic agents

In a previous study, rheumatoid arthritis (RA) patients who failed to respond to methotrexate were shown to experience positive results with fostamatinib disodium (R788), an oral spleen tyrosine kinase (Syk) inhibitor that is thought to block immune cell signaling involved with bone and cartilage destruction.

In the current study, RA patients who failed to respond to biologic agents were studied. In contrast to the prior study, however, fostamatinib was not effective in this group of patients, although the drug did appear to be safe. Results of this Phase II trial are published in the February issue of Arthritis & Rheumatism, a journal of the American College of Rheumatology (ACR).

The drug is under development by Anglo-Swedish major AstraZeneca (LSE: AZN), which acquired an exclusive worldwide license for the global development and commercialization of fostamatinib from US firm Rigel Pharmaceutical for its late-stage investigational product for RA and additional indications, in a deal that could cost the UK-headquartered company as much as $1.25 billion (The Pharma Letter February 16, 2010). Last September, AstraZeneca started the Phase III trials program for fostamatinib.