AstraZeneca has reported top-line results from OSKIRA-1 Phase 3 study, assessing the efficacy and safety of fostamatinib in rheumatoid arthritis (RA) patients.
Fostamatinib is the first oral spleen tyrosine kinase (SYK) inhibitor being developed to treat RA.
Evaluation of signs and symptoms of RA as measured by ACR20 response rates and an X-ray endpoint known as mTSS (modified Total Sharp Score) had been the two primary endpoints of OSKIRA-1.
AstraZeneca global medicines development executive vice president and chief medical officer Briggs Morrison said that the top-line results demonstrate fostamatinib's efficacy on the signs and symptoms of rheumatoid arthritis.
"We will await the results of the remaining Phase 3 studies, OSKIRA-2 and OSKIRA-3, to further evaluate and characterise the profile of fostamatinib as a potential treatment for rheumatoid arthritis," Morrison added.
A statistically significant improvement in ACR20 response rate at 24 weeks was achieved by fostamatinib in both the 100mg twice daily group and the group that received 100mg twice daily for four weeks subsequent to 150mg once daily.
A statistically significant difference in mTSS compared to placebo at 24 weeks for either dose was not achieved.
Consistent safety and tolerability findings for fostamatinib were noted while the commonly reported adverse events include hypertension, diarrhoea, nausea, headache and nasopharyngitis.
A total of 923 patients were randomised in the study that showed an inadequate response to methotrexate (MTX) and evaluated the effectiveness of two dosing regimens of fostamatinib in combination with MTX versus placebo in combination with MTX.
The company anticipates results from OSKIRA-2 and OSKIRA-3 in the second quarter of 2013.