Efficacy and Safety of Golidocitinib for Rapidly Progressive Interstitial Lung Disease

The goal of this clinical trial is to learn whether adding the JAK inhibitor golidocitinib to standard corticosteroid therapy works to treat rapidly progressive interstitial lung disease (RP-ILD) in patients with acute worsening. It will also learn about its safety compared to standard treatment without JAK inhibitors (i.e., corticosteroids plus other immunosuppressants such as mycophenolate mofetil, tacrolimus, cyclophosphamide, or biologics). The main questions it aims to answer are: * How much does the addition of golidocitinib improve lung function, measured by the absolute change in FVC (mL), after 12 weeks of treatment? * How does it compare to standard therapy in terms of changes in FVC% predicted, oxygenation index, chest CT score, need for invasive respiratory support, all-cause mortality, relapse rate, and incidence of opportunistic infections? Researchers will compare the golidocitinib group (golidocitinib 150 mg once daily plus corticosteroids) to the control group (corticosteroids plus non-JAK inhibitor immunosuppressants). All patients receive high-dose corticosteroids (prednisone equivalent ≥1 mg/kg/day) with a tapering regimen. Participants will: * Receive either golidocitinib plus corticosteroids or control treatment for 12 weeks * Visit the clinic for check-ups, blood tests, and lung function tests at weeks 1, 2, 4, 6-8, and 12 * Have chest high-resolution CT scans at weeks 2, 4-6, and 12 to monitor disease progression * Be monitored for adverse events and efficacy outcomes throughout the 12-week period

Inclusion Criteria: * Age ≥ 18 years * Meet the diagnostic criteria for rapidly progressive interstitial lung disease (RP-ILD) and require treatment with corticosteroids and immunosuppressants, defined as: Acute worsening of cough and dyspnea occurring within 1 month; Chest CT showing ILD manifestations with new or worsening exudative lesions (ground-glass opacities and/or consolidation); Presence of respiratory failure (PaO₂ \< 60 mmHg at rest without oxygen supplementation, or SpO₂ \< 90% on room air), or significant worsening of hypoxemia (a decrease in PaO₂ of ≥ 10 mmHg), or a clear decline in two recent pulmonary function tests: a decrease in FVC % predicted of ≥ 10% and/or a decrease in DLCO % predicted of ≥ 15% accompanied by a decline in FVC; Exclusion of heart failure or fluid overload, pulmonary infectious diseases, and pulmonary embolism * No prior treatment with JAK inhibitors * Able to comply with scheduled follow-up visits * Patient and family members understand the study protocol, are willing to participate, and are able to provide written informed consent. Exclusion Criteria: * The patient or family members are unable to understand the conditions and objectives of this study, or are unable to provide informed consent * Subjects who are unable to comply with the follow-up schedule as required by the protocol, including those who cannot cooperate with pulmonary function testing * Presence of other severe diseases that, in the investigator's opinion, may affect patient safety or compliance * Any significant clinical or laboratory abnormalities that, in the investigator's opinion, may affect the safety evaluation * Oxygenation index ≤ 100, and/or requirement for invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO) support * Pregnant or lactating women, as well as patients who are unable to use effective contraception during the study period and within 3 months after the end of the study * Presence of contraindications to golidocitinib administration, including a history of allergy to relevant drugs, or presence of active and uncontrolled infections, such as evidence of HIV, HBV (HBsAg-positive, HBV-DNA-positive or ≥ 1000 copies/mL), HCV (anti-HCV antibody-positive or HCV-RNA-positive), or any symptomatic bacterial, viral, parasitic, or fungal infection requiring treatment * Need for concomitant use of acetaminophen or propacetamol, or preparations containing these ingredients