Cost calculation model of introducing Upadacitinib and Risankizumab for adult ulcerative colitis and Crohn’s disease in the Kingdom of Saudi Arabia

Background: Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), affects approximately 4.9 million individuals globally. Advanced therapies have significantly improved IBD management; however, maintenance doses commonly exceed labeled recommendations for optimal efficacy. This study aimed to estimate the financial impact of introducing Risankizumab (RISA) for CD and Upadacitinib (UPA) for UC treatment in Saudi Arabia (KSA), incorporating adjusted dosing practices rather than label doses alone. Methods: Cost-calculation model (CCM) was developed to estimate average monthly costs per patient, capturing complexities like induction, maintenance adjustments, discontinuation, switching, re-induction, and death. Data on adjusted dosing were collected via two expert interviews. The CCM compared scenarios “with” and “without” UPA for UC, and “with” and “without” RISA for CD, analyzing financial impacts over a 5-year horizon, from the payer’s perspective. Results: Adjusted UC treatment doses increased five-year costs by 22% compared to label doses. Introducing UPA with adjusted dosing resulted in a 6.7% higher cost versus scenarios without UPA, based on tender prices. For CD, adjusted dosing increased treatment costs by 24.5% compared to label doses. However, adding RISA with adjusted dosing slightly reduced the total drug cost by 0.35%. Conclusion: Expert interviews and detailed patient pathway modeling indicated substantial cost increases for UC and CD treatments in KSA when adjusted doses were considered. The introduction of UPA and RISA under adjusted dosing yielded minor financial differences, with potential implications for economic evaluations in other regions.