Treatment of PANCA-Associated Interstitial Lung Disease

Initial Treatment Approach

The American College of Rheumatology recommends initiating glucocorticoids as first-line therapy for PANCA-ILD, as this falls under systemic autoimmune rheumatic disease-associated ILD (SARD-ILD) other than systemic sclerosis 1, 3
The American College of Rheumatology conditionally recommends combining glucocorticoids with one of the following immunosuppressive agents as first-line options: mycophenolate, rituximab, cyclophosphamide, or azathioprine 1, 2
Mycophenolate should be started at 500-1000 mg twice daily, titrating to 1500 mg twice daily based on tolerance, as recommended by the American College of Rheumatology 4
Rituximab is particularly preferred for rapidly progressive disease, according to the American College of Rheumatology 5
Cyclophosphamide can be used either intravenously (500-750 mg/m² every 4 weeks for 6 months) or orally (2 mg/kg/day, maximum 200 mg daily), as recommended by the American College of Rheumatology 4
Azathioprine should be started at 50 mg daily, gradually increasing to 2-3 mg/kg/day, as recommended by the American College of Rheumatology 4

The American College of Rheumatology recommends avoiding long-term glucocorticoids (>3-6 months) as maintenance therapy for PANCA-ILD 1, 3
If disease progresses despite first-line therapy, the American College of Rheumatology recommends switching or adding one of the following agents: mycophenolate, rituximab, cyclophosphamide, or nintedanib 1, 2
The American College of Rheumatology conditionally recommends against adding pirfenidone unless the patient specifically has rheumatoid arthritis-associated ILD 1, 2

For life-threatening rapidly progressive disease, the American College of Rheumatology recommends pulse intravenous methylprednisolone (1000 mg daily for 3 days) as first-line therapy, followed by immediate addition of rituximab or cyclophosphamide 5
The American College of Rheumatology also recommends considering IVIG as an adjunctive option for rapidly progressive disease, particularly if infection risk is high or rapid onset of action is needed 5, 7

The American College of Rheumatology recommends monitoring CBC with differential and LFTs at baseline, 2-3 weeks after starting mycophenolate, 2-3 weeks after dose increases, then every 3 months on stable dosing 4
The American College of Rheumatology recommends monitoring CBC with differential 10-14 days after each IV cyclophosphamide dose or after starting oral therapy, as well as urinalysis every 4-8 weeks during treatment and annual urine cytology after completing cyclophosphamide 4
The American College of Rheumatology recommends monitoring CBC with differential and LFTs at baseline, 2-3 weeks after starting azathioprine, 2-3 weeks after dose changes, then every 3 months 4

The American College of Rheumatology recommends never relying on glucocorticoids alone for maintenance therapy beyond 3-6 months and always combining with steroid-sparing immunosuppression 1, 3
The American College of Rheumatology recommends against combining antifibrotics (nintedanib/pirfenidone) with mycophenolate upfront unless there is documented progression on mycophenolate alone 1, 2
The American College of Rheumatology conditionally recommends against using methotrexate for PANCA-ILD treatment, as it is conditionally recommended against for all SARD-ILD 1, 3
The American College of Rheumatology recommends ruling out infection before initiating or escalating immunosuppression, particularly in patients with acute respiratory deterioration 6
The American College of Rheumatology recommends monitoring for treatment-related complications, including cyclophosphamide-related hemorrhagic cystitis and infertility, mycophenolate-related cytopenias, and rituximab-related infections 4

The American College of Rheumatology recommends early referral for lung transplant evaluation before patients deteriorate to the point of ineligibility, particularly if progression occurs despite optimal medical management 1