Cost-consequence analysis of extended loading dose of anti-VEGF treatment in diabetic macular edema patients

Abstract

Background: The DRCR.net Protocol T clinical trial assessed the comparative efficacy and safety of anti-VEGF treatments including aflibercept, ranibizumab and bevacizumab in diabetic macular edema (DME). Post -hoc analyses showed that after a 12-week induction period, there was still DME resolution in an increasing number of patients through week 24. Purpose: To assess clinical and cost consequences of extending the anti-VEGF loading dose from 3 to 6 monthly injections in patients with persistent DME in Spain. Methods: From a hospital pharmacy perspective, a cost-consequence analysis model was developed to estimate the incremental cost needed to obtain an additional response at month 6. To estimate drug treatment costs, ex-factory prices (€, 2019) were considered for aflibercept, ranibizumab and bevacizumab. Response/nonresponse rates at 3/6 months were obtained from the Protocol T 24-week post hoc analysis (n = 546). Persistent DME was present in 50.8 and 31.6% of the 190 aflibercept-treated patients at month 3 and month 6, respectively. Of the 176 ranibizumab- and 180 bevacizumab-treated patients, 53.2 and 72.9%, respectively, had persistent DME at month 3, and 41.5 and 65.6%, respectively, had persistent DME at month 6. Sensitivity analysis considered the split of bevacizumab vials. Results: Extending the loading dose in nonresponder patients would cost €214,862.57, €208,488.98 and €134,483.16 to obtain 37, 21 and 13 additional aflibercept, ranibizumab and bevacizumab responder patients, respectively. The total number of extended injections (months 3-6) used in patients with persistent DME at month 6 was 180, 219 and 354 for aflibercept, ranibizumab and bevacizumab, respectively. Conclusions: To extend the anti-VEGF loading dose from 3 to 6 injections necessitates investing €5882.77 (8 injections), €10,091.03 (14 injections) and €10,198.59 (30 injections) per additional responder patient (3-month nonresponders and 6-month responders) to aflibercept, ranibizumab and bevacizumab, respectively. For the total of patients treated, on average €7927.02 (14 injections) per additional responder patient would be needed.