Long‑Term Management of Interstitial Lung Disease

First‑Line Immunosuppressive Therapy for CTD‑Associated ILD

• Mycophenolate (target dose ≈ 2 g/day) is the preferred first‑line agent for systemic sclerosis, rheumatoid arthritis, idiopathic inflammatory myopathies, mixed connective tissue disease, and Sjögren disease‑associated ILD (strong recommendation). 1
• Alternative first‑line options include rituximab (especially when active inflammatory arthritis, myositis, or Sjögren neuropathy is present), cyclophosphamide, and azathioprine (conditional/weak recommendation). [1][2]3
• Tocilizumab is conditionally recommended as a first‑line therapy for systemic‑sclerosis‑ILD and mixed‑connective‑tissue‑disease‑ILD (conditional recommendation). [1][3]
• Glucocorticoids should be avoided in systemic‑sclerosis‑ILD because of a strong association with scleroderma renal crisis (strong recommendation against use). [1][3]
• For other CTD‑ILD, glucocorticoids may be used only as short‑term bridging (≤ 3 months) at ≤ 15 mg/day prednisone when switching agents (conditional recommendation). [1][3]

Agents to Avoid in ILD

• Methotrexate, leflunomide, tumor‑necrosis‑factor inhibitors, and abatacept should not be used for ILD treatment because they may exacerbate lung disease (recommendation against). [1][4]

Definition of Disease Progression

• Progression is defined as any of the following within 24 months:

Management of Progressive Disease Despite First‑Line Therapy

• If progression occurs, switch to an alternative first‑line immunosuppressant (e.g., from mycophenolate to rituximab or cyclophosphamide) (recommendation). 1
• Add nintedanib to ongoing immunosuppression for progressive fibrosing disease, particularly when substantial fibrosis or a usual interstitial pneumonia (UIP) pattern is present on CT (conditional recommendation). [5][1]
• The choice between switching agents versus adding antifibrotic therapy should be guided by the speed of progression and the relative contribution of fibrotic versus inflammatory disease (expert opinion). [1][3]

Antifibrotic Therapy Recommendations

• Nintedanib – conditionally recommended as a first‑line option for systemic‑sclerosis‑ILD and for rheumatoid‑arthritis‑ILD (conditional recommendation; panel did not reach full consensus for RA‑ILD). [1][5]
• Nintedanib – recommended against as first‑line therapy for Sjögren‑disease‑ILD, inflammatory‑myopathy‑ILD, and mixed‑connective‑tissue‑disease‑ILD (recommendation against). 1
• Pirfenidone – conditionally recommended against as first‑line therapy for systemic autoimmune rheumatic disease‑associated ILD (conditional recommendation). 1
• Up‑front combination of nintedanib or pirfenidone with mycophenolate is not advised as first‑line therapy (recommendation against). 1
• Antifibrotics should not be added to mycophenolate in patients without documented ILD progression (recommendation against). 1

Monitoring Protocol

Rapidly Progressive ILD

• Defined as rapid evolution from minimal symptoms to respiratory failure (requiring high‑flow oxygen or mechanical ventilation) within days to weeks, without an alternative cause such as infection or heart failure (definition). [1][2]
• Treatment strategy: intravenous glucocorticoids plus 1–2 additional immunosuppressive agents (rituximab, cyclophosphamide, IVIG, mycophenolate, calcineurin inhibitor, or JAK inhibitor) (strong recommendation). [2][3]
• For severe disease or anti‑MDA‑5 positivity, dual or triple combination therapy is advised (strong recommendation). [2][3]
• Early referral for lung transplantation should be considered in rapidly progressive cases (strong recommendation). [2][3]
• Rituximab and cyclophosphamide are preferred over IVIG; IVIG may be chosen when infection risk is high (conditional recommendation). [2][3]

Supportive Care & Screening

• Pulmonary hypertension screening: obtain an echocardiogram when PH is suspected; up to 85 % of patients with end‑stage fibrotic ILD develop PH (recommendation). 6

Critical Pitfalls & Implementation

• Long‑term glucocorticoids should not be used for ILD progression; limit to short‑term bridging when changing immunosuppressive agents (strong recommendation against). 4
• Monitor for drug‑induced ILD; DMARDs (including TNF inhibitors, sulfasalazine, cyclophosphamide, rituximab, leflunomide, methotrexate, sulfonamides) carry an approximate 1 % risk (recommendation). 6
• Do not delay antifibrotic therapy in progressive fibrosing disease with substantial fibrosis or a UIP pattern, as this pattern predicts poor prognosis (strong recommendation). 5
• Multidisciplinary collaboration between rheumatology and pulmonology is essential when initiating ILD treatment, especially in asymptomatic patients with stable mild disease (strong recommendation). [1][4]

Treatment for Interstitial Lung Disease

First-Line Treatment by ILD Subtype

• The American College of Rheumatology recommends mycophenolate as the preferred first-line immunosuppressive agent for all forms of systemic autoimmune rheumatic disease-associated ILD, including systemic sclerosis, rheumatoid arthritis, idiopathic inflammatory myopathies, mixed connective tissue disease, and Sjögren disease 7, 8, 9
• The American Thoracic Society suggests initiating antifibrotic therapy with either nintedanib or pirfenidone for idiopathic pulmonary fibrosis, as both reduce annual FVC decline by 44-57% 10, 8
• For connective tissue disease-associated ILD, alternative first-line options include rituximab, cyclophosphamide, and azathioprine, with the strength of evidence being conditional 7, 8, 9

Treatment of Progressive Disease Despite First-Line Therapy

• The American College of Rheumatology recommends switching to an alternative immunosuppressant, such as from mycophenolate to rituximab or cyclophosphamide, for ILD progression despite initial immunosuppressive treatment 7, 8
• Adding nintedanib to ongoing immunosuppression is also recommended for progressive disease, with evidence showing efficacy in slowing lung function decline 7, 10, 8, 9

Specific Agents to Avoid

• The American College of Rheumatology advises against using methotrexate, leflunomide, TNF inhibitors, and abatacept for ILD treatment, as they may exacerbate the condition 9, 11

Emerging Therapies

• Tocilizumab is FDA-approved for systemic sclerosis-associated ILD, particularly effective in patients with early disease and elevated inflammatory markers, according to the FDA 8

Co-Management and Monitoring

• The American Thoracic Society recommends co-management with pulmonology for determining treatment necessity in asymptomatic patients with stable, mild ILD, with monitoring frequency based on disease severity 8, 9
• For mild disease, pulmonary function tests (PFTs) should be performed every 6 months for 1-2 years, while moderate-to-severe or progressive disease requires PFTs every 3-6 months 8