AstraZeneca’s Fostamatinib scores high in PhIIb trial

Fostamatinib AstraZeneca’s novel oral therapy Fostamatinib demonstrates positive Response in rheumatoid arthritis patients. The experimental agents fostamatinib achieved the goal in a mid-stage clinical trial, performing better than a placebo at treating symptoms of rheumatoid arthritis. The results of the Phase II Study published in the New England Journal of Medicine.

Fostamatinib (R788), a new oral syk inhibitor, was in-licensed from US firm Rigel Pharmaceuticals earlier this year.  Under the deal, AstraZeneca agrees to pay $100 million to Rigel with more than $1.2 billion in regulatory and sales milestones for the development and commercialization right of Fostamatinib .

The fostamatinib Phase IIb study, known as TASKi2, enrolled 457 patients who were also being treated with methotrexate, but were resistant to the drug.   It measured their improvement in areas including tenderness and swelling in the joints, pain, physical function, and overall health.  The patients were divided into groups which receiving either 100 milligrams of fostamatinib twice per day, 150 milligrams once per day, or the placebo. In the study, the investigators found that 67 percent of the methotrexate-resistant patients taking 100 mg of the experimental therapy twice daily achieved at least a 20 percent improvement in a range of symptoms such as swollen joints, pain and physical function. Impressively, 36% of the group achieved an ACR 20 response in less than a week. 57% patients taking a once-daily dose of 150 mg hit the same ACR 20 mark, compared with 35 percent of the placebo arm. The report noted that the most common side effects were diarrhea, upper respiratory infection, and a low white blood cell count.

In this study, we saw a significant clinical benefit in this rheumatoid arthritis population and a manageable safety profile,” said Mark Genovese, Division of Rheumatology, Stanford University, Palo Alto, USA, adding: “Based on the data, further study of fostamatinib as an oral agent for the treatment of patients with rheumatoid arthritis is certainly warranted.”

AstraZeneca plans to initiate the Phase III clinical trial program OSKIRA (Oral Syk Inhibition in Rheumatoid Arthritis)  for fostamatinib shortly.