Start of Phase III RA program and transfer of extension study to AstraZeneca triggered payments.
Rigel Pharmaceuticals earned $25 million from AstraZeneca for the fulfillment of two milestones under their agreement for the clinical development of fostamatinib (R788). The first milestone is for AstraZeneca’s initiation of the Phase III program in patients with rheumatoid arthritis (RA). The second milestone marks the completed transfer of the fostamatinib long-term, open-label extension study from Rigel to AstraZeneca.
Fostamatinib is an oral spleen tyrosine kinase (syk) inhibitor. Suppressing syk is thought to block signaling in multiple cell types involved in inflammation and tissue degradation in RA.
In February Rigel granted AstraZeneca exclusive rights to the future development and commercialization of fostamatinib. At the time, AstraZeneca said that the initial focus of its Phase III program called OSKIRA (oral syk inhibition in rheumatoid arthritis) would be in patients with RA who have had an inadequate response to disease-modifying antirheumatic drugs (DMARDs) including methotrexate (MTX).
Today AstraZeneca detailed the scope of its global clinical program, saying that it will include three Phase III studies assessing the efficacy and tolerability of fostamatinib. Results are expected to allow for the filing of marketing applications with both the FDA and EMEA in 2013.
The OSKIRA program will include two 12-month trials in patients inadequately controlled by DMARDs including MTX, a six-month study in patients who have previously responded inadequately to anti-TNF therapy, and long-term safety extension studies of the 2,000+ patients in the Phase II and Phase III studies. These will be double-blind, randomized, placebo-controlled studies for the first six months, and the two one-year studies will continue for a six-month active-extension period.
The primary endpoint for all three studies will be ACR 20 at six months. One of the two one-year trials includes the change in structural progression at six months as a primary endpoint. The OSKIRA trials will test two dose regimens of fostamatinib: 100 mg bid and 100 mg bid for four weeks followed by a maintenance dose of 150 mg qd.