Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fatal interstitial lung disease characterized by irreversible scarring, leading to respiratory failure. With limited treatment options and a poor prognosis, new therapies are urgently needed. This study investigates a novel cell therapy targeting pathological fibroblasts, a key driver of fibrosis.

Single-cell analyses identify CTHRC1+FAP+ fibroblasts as a collagen-producing subpopulation crucial in IPF progression. Chimeric antigen receptor (CAR) technology enables precise targeting of these cells. While CAR-Treg therapy has shown promise in preclinical models, its clinical translation requires careful safety evaluation regarding infection risk, potential tumor promotion, and immune reconstitution.

This trial employs an innovative approach using engineered dendritic cells (DCs). CAR technology is applied to generate immunosuppressive CAR-DCs (iCAR-DCs) designed to target FAP, localize to fibrotic lung areas, and attenuate fibrosis without eliciting a detrimental immune response. Preliminary mouse studies demonstrated that iCAR-DC administration following lung injury significantly reduced fibrosis without apparent organ toxicity and improved survival.

This single-arm trial aims to evaluate the efficacy and safety of this immunosuppressive CAR-DC therapy in patients with end-stage IPF. Key assessments will include changes in lung function, fibrosis extent on imaging, and comprehensive monitoring of potential adverse effects, particularly infections, tumor markers, and immune parameters.

Inclusion Criteria:

1. Aged between 18 and 75 years, inclusive, with a diagnosis of idiopathic pulmonary fibrosis (IPF).

2. Ability to verbally confirm understanding of the risks, benefits, and alternative treatments associated with immunosuppressive CAR-DC therapy. Provision of written informed consent by the patient or their legally authorized representative prior to participation.

3. Evidence of disease progression (worsening pulmonary fibrosis and declining lung function) despite treatment with standard therapies such as pirfenidone, nintedanib, or other appropriate regimens.

4. Meets at least one criterion indicating eligibility for lung transplantation due to interstitial lung disease, while not consenting to a transplant. The criteria include:

1. A decline in forced vital capacity (FVC) ≥10% over a 6-month follow-up period.
2. A decline in diffusing capacity of the lungs for carbon monoxide (DLCO) ≥10% of predicted value over 6 months.
3. Six-minute walk test results showing oxygen saturation <88%, a distance walked <250 meters, or a decline of >50 meters in distance over 6 months.
4. Presence of pulmonary hypertension (PH) confirmed by right heart catheterization or transthoracic echocardiography.
5. Hospitalization due to respiratory functional decline, pneumothorax, or acute exacerbation.

5. No prior cellular immunotherapy within the last 3 months. 6. Hematological parameters meeting the following thresholds: hematocrit >30%, lymphocyte count >0.5 × 10⁹/L, and platelet count >60 × 10⁹/L.

Exclusion Criteria:

1. History of acute exacerbation of IPF within 4 weeks prior to screening or during the screening period.
2. Presence of interstitial lung disease (ILD) other than IPF, including but not limited to: other forms of idiopathic interstitial pneumonia; ILD associated with fibrogenic agents, environmental exposures, or drug toxicity; other occupational lung diseases; granulomatous lung diseases; pulmonary vascular diseases; or ILD related to systemic diseases (e.g., vasculitis, infections such as tuberculosis, connective tissue diseases). Cases with uncertain diagnosis require serological testing and/or multidisciplinary team review for confirmation.
3. Presence of significant active infection.
4. History of malignancy, except for malignancies treated with curative intent and with no recurrence for ≥5 years, resected basal cell or squamous cell skin carcinoma, carcinoma in situ of the cervix, or resected colonic polyps.
5. Significant history of infectious diseases.
6. Presence of psychiatric illness or other conditions that would compromise the patient's ability to cooperate with study requirements, comply with treatment, or undergo monitoring.
7. Known hypersensitivity to any component of the immunosuppressive CAR-DC cell product.
8. History of severe renal failure requiring renal dialysis, or serum creatinine level >2.5 mg/dL.
9. Any contraindication to the investigational product or study procedures.
10. Pregnancy or lactation.
11. History of pulmonary embolism (PE), deep vein thrombosis (DVT), or recurrent thromboembolic events.
12. Uncorrected thrombocytopenia (platelet count <50,000/μL) or systemic coagulopathy (INR >2.5 or aPTT >2.5 times the control value in the absence of anticoagulant therapy), or active bleeding with uncorrectable coagulopathy.
13. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) levels >5.0 times the upper limit of normal (ULN), or total bilirubin >3 mg/dL.