THU0246 Subcutaneous Abatacept: Long-Term Data From the Acquire Trial

Background The Abatacept (ABA) Comparison of Sub[QU]cutaneous (SC) versus Intravenous (IV) in Inadequate Responders to MethotrexatE (MTX) (ACQUIRE) study showed comparable efficacy and safety of SC vs IV ABA over 6 mths.1 Objectives To present 32-mth safety and efficacy data from the long-term extension (LTE) of ACQUIRE, during which all patients (pts) received SC ABA. Methods ACQUIRE was a Phase IIIb, 6-mth, double-blind (DB) study in which pts with active RA (³10 swollen and ³12 tender joint count [SJC and TJC], C-reactive protein (CRP) ≥0.8 mg/dL) refractory to MTX received IV or SC ABA, plus MTX, followed by an open-label LTE when pts received SC ABA 125 mg/wk. Not all pts had reached later time points at time of analysis, as a result of differential enrolment in the trial. Results Of 1372 pts entering the LTE, 1134 (82.7%) remained on therapy at time of reporting. Mean baseline RA duration was 8 yrs, TJC and SJC were 30 and 20, respectively, and HAQ-DI was 1.7. Median (range) ABA exposure was 33 (8–44) mths. The incidence rate (IR; events/100 pt-yrs) of serious adverse events for pts treated with SC ABA in the LTE (8.76 [95% CI: 7.71–9.95]) was comparable with that for SC ABA in the DB period (9.02 [6.31–12.90]) and did not increase with increasing exposure. The IR of overall and serious infections in the LTE (44.80 [41.81–48.01] and 1.72 [1.30–2.27], respectively) did not increase vs the DB period (84.62 [74.50–96.11] and 1.48 [0.62–3.56], respectively). Bacterial, viral and hospitalised infections occurred at IRs of 27.28 (25.16–29.57), 18.25 (16.61–20.06) and 1.55 (1.16–2.07) during the LTE. The IR of malignancy did not increase in the LTE (1.19 [0.86–1.66]) vs the DB period (0.59 [0.15–2.36]). Injection-site reactions occurred in 27 (2.0%) pts in the LTE (none serious) and 19 (2.6%) pts in the DB period. Overall, 139/1365 (10.2%) and 1/153 (0.7%) pts experienced immunogenicity during the LTE and DB periods, respectively. ACR responses were maintained and comparable with original SC and IV groups: at Day 169, ACR 20 response rates were 80.2% (95% CI: 77.2, 83.2) and 80.0% (77.0, 83.0) and at Day 981 were 84.8% (80.8, 88.8) and 84.7% (80.7, 88.8). DAS28 (CRP)