Background Assessment of the real-world effectiveness of newer biologics such as abatacept is essential in determining true benefits in routine practice. Patient registries represent a valuable supplement to randomized controlled trials including real world durability, and improvement of function over time.
Objectives A large Canadian database was used to determine effectiveness of abatacept in real world RA patients including how many people need to be treated to improve 1 RA patient by a minimally important difference (MID) of the HAQ.
Methods RA patients administered abatacept via clinic or home infusions from the Orencia Response Program network, between 2006 and Feb. 2011 with follow-up evaluation(s) were included. The number needed to treat (NNT) to improve HAQ by at least the MID (≥0.22) and abatacept survival until last follow up were calculated overall; and for abatacept as first or subsequent biologic.
Results Among the 2,929 patients enrolled, 1,771 (60.5%) were eligible for the study (79.2% had past TNFi) with a mean (SD) follow up of 13.8 (12.3) months. Mean (SE) durability of treatment was 26.8 (0.53) months; where 66% were still on abatacept at 12 and 53% at 24 months. The survival was longer where abatacept was the first biologic vs. post TNFi (P=0.0001). In abatacept as 1stbiologic, 70% achieved MID in HAQ vs. 71% if post TNFi (P=0.65) with NNT=1.4 in each group and there were also no differences in % achieving MID comparing no past biologic to 2, 3 or 4 pervious biologics. Increased baseline HAQ (OR 2.13 (1.89, 2.39)) and less years of RA (OR 0.98 (0.97, 0.99)) were significant predictors of achieving the MID for HAQ. For those staying on abatacept, the mean improvement in HAQ increased over time; changing at 6, 12, 18 and 24 months by -0.29, -0.41, -0.45 and – 0.51 respectively with no difference between abatacept as first biologic vs. post TNFi (unadjusted) and if adjusting for baseline differences, change in HAQ was better as first biologic (p<0.001).
Conclusions Abatacept is effective in improving HAQ in RA despite long disease duration. For those still on abatacept, HAQ continued to improve over the first 2 years. The durability of abatacept is better as first biologic but NNT to improve HAQ is the same post DMARDs and TNFi. This can help to inform treatment decisions.
Disclosure of Interest J. Pope Grant/Research support from: This study was supported by a grant from BMS. The protocol was developed by the authors for data analysis., E. Rampakakis: None Declared, J. Sampalis: None Declared, O. Desjardins: None Declared