A total of 477 patients was required for the sample to have an 80% power for demonstrating non-inferiority, according to the assumptions stated in the power calculation. At the time it was stopped, a total of 149 patients had been enrolled and 122 randomised to treatment.
There was evidence of a statistically significant difference between use of an alternative TNF inhibitor and rituximab, with a mean reduction in DAS28 at 24 weeks (primary endpoint) of 0.3 (95% CI -0.45 to 1.05), favouring the TNF inhibitor (p=0.022), but this was not maintained at week 48. There was no evidence of a clinically or statistically significant difference in DAS28 for abatacept compared with rituximab at any time point.
The health economic analysis suggested that switching to an alternative TNF inhibitor may be cost-effective compared with rituximab (ICER £5332.02 per QALY gained). However the value of information analysis indicated that it would be highly valuable to the NHS to reduce the current uncertainty regarding the effectiveness of alternative TNF inhibitor compared with rituximab in the management of rheumatoid arthritis.