What is the recommended treatment for Interstitial Lung Disease (ILD) in a patient with Systemic Lupus Erythematosus (SLE) currently on rituximab and prednisone with controlled nephritis?

Treatment of Interstitial Lung Disease in SLE Patient with Controlled Nephritis

For a patient with SLE who has controlled nephritis on rituximab and prednisone but has developed ILD, mycophenolate mofetil is the recommended treatment option.

First-Line Treatment Options for SLE-ILD

Recommended Approach

1. Mycophenolate Mofetil (MMF)

   • First-line agent for SARD-ILD including SLE-ILD 1
   • Initiate at 500 mg twice daily and gradually increase by 500 mg weekly 2
   • Target maintenance dose: 1000-1500 mg twice daily (maximum 3 g/day) 2
   • Takes 4-8 weeks to demonstrate clinical effect, with maximum benefit after 3-6 months 2

2. Continue Rituximab

   • Already part of the patient's regimen with good control of nephritis
   • Conditionally recommended as a first-line ILD treatment option 1
   • Effective for both lupus nephritis and ILD 3, 4
   • Dosing: typically 375 mg/m² weekly for 4 weeks or 1000 mg on days 0 and 14 2

3. Prednisone Management

   • Continue current prednisone dose temporarily
   • Aim to taper to ≤5 mg/day once ILD is controlled 4
   • For SLE-ILD, glucocorticoids are conditionally recommended as part of first-line treatment 1

Monitoring and Follow-up

• Complete blood count, liver function tests, and renal function:
  • Every 1-2 weeks during initial titration
  • Monthly for 3 months
  • Every 2-3 months once stable 2
• Pulmonary function tests (FVC, DLCO) every 3-6 months 2
• High-resolution CT scan of chest at baseline and as clinically indicated

Alternative Options (If First-Line Treatment Fails)

If Progressive ILD Despite First-Line Treatment:

1. Cyclophosphamide

   • Conditionally recommended for SARD-ILD progression 1
   • Typically administered as IV pulses (500-750 mg/m²) monthly for 6-12 months 2
   • Consider for rapidly progressive ILD when other options have failed 2
   • Has shown efficacy in combination with rituximab and methylprednisolone pulses 5

2. Pulse Methylprednisolone

   • Consider for acute exacerbations or rapidly progressive ILD 1
   • Typical dosing: 500-1000 mg IV for 3 consecutive days 5
   • Should be followed by oral prednisone with a tapering schedule

3. Pirfenidone

   • Not recommended as first-line treatment for SARD-ILD 1
   • May be considered for RA-ILD but not specifically recommended for SLE-ILD 1

Potential Pitfalls and Considerations

• Avoid high-dose oral steroids long-term

  • While effective for acute management, long-term high-dose steroids lead to significant morbidity
  • Several studies show successful treatment of lupus nephritis with rituximab while reducing or withdrawing steroids 3, 4

• Infection risk

  • Combination of rituximab and mycophenolate increases infection risk
  • Regular monitoring for signs of infection is essential
  • Consider antimicrobial prophylaxis if appropriate

• Pregnancy considerations

  • Mycophenolate is absolutely contraindicated in pregnancy and lactation 2
  • Women of childbearing potential must use reliable contraception

• Treatment response assessment

  • If no improvement or worsening after 3-6 months, consider alternative therapy
  • Definition of progression: decline in FVC of ≥10% predicted value, or decline in FVC of 5-10% with worsening symptoms or increased fibrosis on HRCT 1

The combination of mycophenolate mofetil with continued rituximab provides targeted therapy for both SLE-ILD and maintenance of nephritis control, while allowing for potential reduction in steroid exposure over time.