Abstract Background Risankizumab (RZB) is effective for Crohn’s disease (CD) maintenance, but loss of response (LOR) during subcutaneous (SC) therapy is a clinical challenge. A potential strategy is the administration of a 1200 mg intravenous (IV) rescue dose. Although clinical trials support this IV rescue dose as a potential strategy, real-world data on its effectiveness remain scarce. Methods We conducted a retrospective, single-centre cohort study of CD patients initiating RZB induction between January 2023 and September 2025. Patients who completed induction (n = 47) were divided into two groups: the ‘Rescue Group’ (RG), who received at least one RZB 1200 mg IV infusion for LOR during maintenance, and the ‘Non-Rescue Group’ (NRG), who did not. We compared baseline characteristics (including Simple Endoscopic Score for Crohn’s Disease SES-CD), prior treatments, and biomarkers between groups. Data were extracted retrospectively from electronic medical records. Results Of 47 patients completing RZB induction, 15 required IV rescue (RG) and 32 did not (NRG). Baseline Comparison: At RZB induction, RG had significantly longer disease duration (median 17 vs 9 yrs, p = 0.0160) than NRG. Prior biologic exposure (bio-experienced) was significantly more frequent in RG (15/15, 100%) compared to NRG (22/32, 68.8%, p = 0.0193). RG also had lower baseline Leucine-rich alpha-2 glycoprotein (LRG) (median 21.4 vs 34.3 mg/dL, p = 0.0026) and trended towards higher baseline SES-CD (median 15 vs 6, p = 0.0569). IV Rescue Effectiveness (n = 15): Reasons for rescue (duplicates allowed) were clinical (n = 11), biomarker (n = 3), or endoscopic (n = 3) flare. Most infusions (13/15, 87%) were scheduled. LOR flares were characterised by low serum C-reactive protein (CRP) (median 6.3 mg/L). However, LRG levels were elevated (mean 19.9 mg/dL) and significantly decreased post-IV rescue (mean 17.35 mg/dL, p 0.05). Treatment Persistence: The Kaplan-Meier estimated persistence rate (endpoint: hospitalisation, surgery, or biologic switch) at 365 days was 93.3% (14/15) (median follow-up 343 days). No serious adverse events (SAEs) related to the IV rescue were observed in this group. Conclusion RZB IV rescue therapy demonstrated high 1-year persistence and a favourable safety profile, suggesting it is a promising treatment option in bio-experienced patients with LOR. However, as this was a single-centre retrospective analysis, further large-scale studies are needed to validate its effectiveness. Conflict of interest: Dr. Nagai, Hiroshi: No conflict of interest Kakuta, Yoichi: No conflict of interest Iwaki, Hideya: No conflict of interest Okamoto, Daisuke: No conflict of interest Shimoyama, Yusuke: No conflict of interest Naito, Takeo: No conflict of interest Moroi, Rintaro: No conflict of interest Shiga, Hisashi: No conflict of interest Masamune, Atsushi: No conflict of interest
Nagai et al. (Thu,) studied this question.