# Outcomes of an Intravenous to Subcutaneous Infliximab (CT‐P13) Strategy in Takayasu Arteritis: A Proof‐of‐Concept Prospective Study

## TL;DR

Switching from intravenous to subcutaneous infliximab in Takayasu arteritis patients maintained remission and was well tolerated over 12 months.

## Contribution

Demonstrates feasibility of subcutaneous infliximab as a maintenance strategy in Takayasu arteritis.

## Key findings

- 12-month drug persistence was 77.8% after switching to subcutaneous infliximab.
- 87.5% of patients remained in remission at 12 months with stable CRP, ESR, and PETVAS.
- No serious adverse events occurred, and damage accrual remained stable.

## Abstract

To evaluate persistence, outcomes, safety, and remission maintenance after switching from intravenous infliximab (IV‐IFX) to subcutaneous infliximab (SC‐IFX, CT‐P13) in patients with Takayasu arteritis (TA).

We conducted a prospective, single‐center, proof‐of‐concept observational study of consecutive adults with TA in sustained clinical, laboratory, and positron emission tomography (PET) remission switched from stable 5 mg/kg dose IV‐IFX to SC‐IFX 120 mg every two weeks. Assessments at baseline, 6 months, and 12 months included Indian Takayasu Clinical Activity Score (ITAS2010), Disease Extent Index‐Takayasu (Dei.TAK), PET Vascular Activity Score (PETVAS), C‐reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), Large Vessel Vasculitis Index of Damage (LVVID), and safety data. The primary objective was 12‐month drug persistence. Secondary outcomes included remission rates, changes in ITAS2010, Dei.TAK, PETVAS, acute‐phase reactants, damage accrual, and safety.

Nine women (median age 35 [interquartile range (IQR) 28–44] years) were included. The median IV‐IFX exposure before the switch was 60 (IQR 24–72) months. Twelve‐month drug persistence was 77.8%. One patient discontinued early due to an injection‐site reaction, and another experienced a relapse at 12 months that required a therapy change. At 12 months, 87.5% (seven of eight) patients remained in remission. CRP and ESR remained stable (P = 0.297 and P = 0.068, respectively). PETVAS was similar to pre‐switch values (P = 0.589). Median LVVID remained stable throughout follow‐up. No serious adverse events occurred.

IV‐IFX to SC‐IFX switching was feasible and well tolerated and generally maintained remission over 12 months in most patients with TA, with stable metabolic imaging and no increase in damage accrual. These findings support SC‐IFX as a practical maintenance strategy, warranting confirmation in larger multicenter cohorts.