Should I continue mycophenolate (Cellcept) in a patient with an acute exacerbation of Usual Interstitial Pneumonia (UIP)?

Management of Acute Exacerbation of UIP in a Patient on Mycophenolate

Mycophenolate should be continued during an acute exacerbation of Usual Interstitial Pneumonia (UIP), while adding high-dose corticosteroids for the acute episode. 1

Rationale for Continuing Mycophenolate

The 2023 American College of Rheumatology (ACR)/American College of Chest Physicians (CHEST) guidelines provide clear direction on this issue:

1. Mycophenolate as first-line therapy: Mycophenolate is recommended as a first-line treatment option for interstitial lung disease (ILD) across systemic autoimmune rheumatic diseases (SARDs) due to its favorable efficacy and safety profile 1.

2. Stability or improvement with mycophenolate: Research evidence shows that mycophenolate treatment is associated with either stable or improved pulmonary physiology over time, even in patients with UIP-pattern injury 2.

3. Risk of discontinuation: Abrupt discontinuation of immunosuppressive agents during acute exacerbations can potentially worsen the underlying disease 1.

Management Algorithm for Acute Exacerbation of UIP

Immediate Management

1. Continue mycophenolate at the current dose 1
2. Add high-dose corticosteroids:
   • IV methylprednisolone 1g/day for 3 days 3
   • Follow with oral prednisone taper 3
3. Provide supportive care:
   • Supplemental oxygen as needed
   • Consider mechanical ventilation for respiratory failure 3

Monitoring During Acute Exacerbation

1. Pulmonary function tests to assess severity and response to treatment
2. High-resolution CT (HRCT) to evaluate extent of ground-glass opacities and consolidation 4
3. Laboratory monitoring:
   • Complete blood count with differential
   • Comprehensive metabolic panel
   • Monitor for infection

After Resolution of Acute Exacerbation

1. Continue mycophenolate as maintenance therapy 1
2. Taper corticosteroids gradually to minimize side effects
3. Regular follow-up with serial PFTs every 3-6 months 1

Histopathological Patterns and Prognosis

Acute exacerbations of UIP can present with three distinct histopathological patterns 4:

1. Diffuse alveolar damage (DAD) - associated with worse outcomes
2. Organizing pneumonia (OP) - generally better prognosis
3. Extensive fibroblast foci - intermediate prognosis

Patients with organizing pneumonia or extensive fibroblast foci patterns tend to have better survival rates than those with diffuse alveolar damage 4.

Potential Pitfalls and Caveats

1. Infection surveillance: Rule out infectious causes of acute deterioration before intensifying immunosuppression.

2. Mycophenolate side effects: Monitor for gastrointestinal (45.3%), infectious (31.9%), and hematological (14.9%) adverse events 5. Common side effects include diarrhea, cytomegalovirus infection, and leukopenia.

3. Drug interactions: Be aware of potential interactions between mycophenolate and other medications that may affect its metabolism or efficacy 6.

4. Lung transplant consideration: For patients with progressive disease despite optimal medical management, early referral for lung transplantation should be considered 1, 3.

By continuing mycophenolate and adding high-dose corticosteroids during an acute exacerbation of UIP, you provide both acute management of the exacerbation and continued control of the underlying disease process, which offers the best chance for improved outcomes in terms of morbidity, mortality, and quality of life.