Treatment Strategy for Patients With RA-ILD

Prior treatment

• Active hepatitis B or C virus infection, active tuberculosis, active herpes zoster infection, or a history of serious infection within 12 weeks prior to study treatment initiation (defined as an infection requiring hospitalization or intravenous antimicrobial therapy).
• Participation in another interventional clinical trial within 4 weeks prior to screening.

Other illness

• Presence of other autoimmune diseases.
• Presence of severe, uncontrolled clinically significant organ dysfunction or other medical conditions that, in the investigator's judgment, would place the participant at unacceptable risk.
• History of malignancy within 5 years prior to screening.
• Known hypersensitivity to tocilizumab, telitacicept, methotrexate, or any of their excipients.
• Any other condition that, in the opinion of the investigator, would make the participant unsuitable for participation in this study.

Lab values

• Severe hypoalbuminemia or serum immunoglobulin G (IgG) level \<6 g/L.
• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>3 × the upper limit of normal (ULN), total bilirubin \>1.5 × ULN, or creatinine clearance (CrCl) \<60 mL/min.

Other

• Pregnant or breastfeeding women, or women planning to become pregnant or breastfeed during the study period.
• Inability to adequately perform pulmonary function testing or other study-related assessments.

• Fulfillment of the 2010 ACR/EULAR classification criteria for RA.
• HRCT findings consistent with interstitial lung disease (ILD), including ground-glass opacities, reticular abnormalities, fibrotic linear opacities, traction bronchiectasis, or other compatible features, with pulmonary infection, cardiogenic pulmonary edema, and alveolar hemorrhage excluded. The extent of ILD involvement must be ≥20% on HRCT, as assessed by central review.
• Pulmonary function impairment defined as forced vital capacity (FVC) \<80% of predicted and/or diffusing capacity of the lung for carbon monoxide (DLCO) \<70% of predicted.
• Participants receiving glucocorticoids prior to enrollment must be on a stable dose of prednisone ≤10 mg/day (or equivalent) for at least 4 weeks before baseline.
• Participants receiving a csDMARD prior to enrollment must be on a stable regimen for at least 4 weeks before baseline.
• Able and willing to provide written informed consent and comply with study requirements, including scheduled visits and follow-up assessments.