Target trial emulation to incorporate real-world data in the estimation of the clinical and cost-effectiveness of biologic treatment

Introduction In the health technology assessment (HTA) of biologic treatments for rheumatoid arthritis (RA), there is limited randomized evidence on treatment effectiveness after first-line treatment failure. We demonstrate how real-world data (RWD) could fill this evidence gap. Methods Target trial emulation (TTE) minimizes biases in the causal analysis of RWD by prespecifying a protocol for a hypothetical randomized clinical trial (RCT) that would estimate the effect of interest. The application of TTE for HTA was illustrated using RWD from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis to estimate the effectiveness of rituximab versus nonbiologic therapy (NBT) after first-line biologic failure, in terms of European Alliance of Associations for Rheumatology response achievement. The effectiveness estimates from RWD were combined with RCT estimates in a meta-analysis. The pooled estimates were entered into an economic model to estimate the incremental cost-effectiveness ratio (ICER) comparing biologic versus NBT strategies. Results Based on RWD, rituximab was associated with higher probabilities of achieving a moderate or good response (0.215 v. 0.174) and a good response (0.090 v. 0.066) as compared with NBT. These probabilities were lower than those estimated from RCT data (moderate or good 0.650; good 0.150). The economic model estimated less time on treatment and lower costs associated with biologics when based on RWD compared with RCT data (mean £63,500 v. £70,000). This resulted in a higher ICER based on RWD compared with RCT data (mean £46,800 v. £34,700 per quality-adjusted life-year gained). Conclusions RWD can provide supplemental evidence on treatment effectiveness where randomized evidence is limited. This can make a meaningful difference to cost-effectiveness estimates. Our results are not intended to inform current RA management.