Should I continue the current induction immunosuppressive regimen (high‑dose glucocorticoids plus cyclophosphamide or rituximab) without tapering now that the patient’s renal function has stabilized with serum creatinine around 2 mg/dL?

Continue Current Induction Immunosuppression with Stabilized Creatinine at 2 mg/dL

Yes, continue the current induction immunosuppressive regimen without tapering now that creatinine has stabilized at 2 mg/dL, as stabilization of renal function indicates treatment response and premature tapering risks disease relapse before achieving complete remission.

Rationale for Continuing Induction Therapy

The stabilization of creatinine at 2 mg/dL represents a positive treatment response, not an endpoint for therapy modification. The specific disease context determines the appropriate duration of induction therapy:

For ANCA-Associated Vasculitis (AAV)

• Continue induction therapy for the full 3-6 month course regardless of creatinine stabilization, as premature discontinuation increases relapse risk 1.
• Cyclophosphamide should be administered for a minimum of 3 months, with continuation up to 6 months if ongoing disease activity persists 1.
• Rituximab induction consists of 4 weekly doses (375 mg/m² weekly × 4 weeks), and this complete course should be administered even with early creatinine stabilization 1.
• Glucocorticoid tapering follows a predetermined schedule starting at 1 mg/kg/day for week 1, then reducing to 0.75 mg/kg/day by week 2,0.5 mg/kg/day by week 4, and continuing the taper to reach 5 mg/day by 6 months 1.

For Lupus Nephritis (Class III/IV)

• Complete the full induction course (typically 6 months with cyclophosphamide or mycophenolate mofetil) before transitioning to maintenance therapy 1.
• Creatinine stabilization alone does not indicate complete remission; proteinuria reduction and serologic improvement must also be assessed 1.
• Total duration of immunosuppression should be at least 36 months (induction plus maintenance) for patients achieving complete remission 1.

For Primary FSGS

• Continue high-dose glucocorticoids for at least 4 weeks and up to 16 weeks or until complete remission is achieved, whichever comes first 1.
• If using calcineurin inhibitors (CNIs), continue at target trough levels for at least 4-6 months before assessing treatment response 1.
• Monitor for CNI nephrotoxicity: if creatinine increases >30% above baseline without plateauing, reduce CNI dose; if creatinine doesn't fall after dose reduction, discontinue the CNI 1.

Critical Monitoring During Continued Induction

Renal Function Surveillance

• Monitor serum creatinine weekly during the continuation of induction therapy to detect any upward trend that might indicate drug toxicity rather than disease activity 1, 2.
• A creatinine increase >30% from the stabilized baseline (i.e., rising above 2.6 mg/dL from current 2.0 mg/dL) warrants reassessment for CNI toxicity if using these agents 1.
• Distinguish between disease progression and drug toxicity: stable or slowly improving creatinine suggests adequate disease control, while rising creatinine may indicate either inadequate immunosuppression or drug-related nephrotoxicity 1.

Disease Activity Assessment

• Continue monitoring proteinuria levels, as reduction in proteinuria is a key indicator of treatment response independent of creatinine stabilization 1.
• For AAV, monitor ANCA titers and inflammatory markers (ESR, CRP) to assess disease activity 1.
• For lupus nephritis, monitor complement levels (C3, C4) and anti-dsDNA antibodies 1.

Common Pitfalls to Avoid

Premature Tapering

• Do not taper immunosuppression based solely on creatinine stabilization without assessing other markers of disease remission (proteinuria, serologies, extrarenal manifestations) 1.
• Patients who achieve only partial remission require indefinite immunosuppression, not early tapering 1.

Misinterpreting Creatinine Stabilization

• A creatinine of 2 mg/dL represents significant renal impairment (GFR approximately 30-40 mL/min/1.73m²) and does not indicate complete renal recovery 1.
• Stabilization indicates treatment is preventing further deterioration, not that maximum benefit has been achieved; continued therapy may yield further improvement 1.

Glucocorticoid Management

• Never abruptly discontinue glucocorticoids in patients on chronic therapy, as this risks adrenal insufficiency 3, 4.
• Follow disease-specific tapering protocols rather than arbitrary schedules based on creatinine levels 1.
• For patients on prednisone >20 mg/day for >12 weeks, maintain PCP prophylaxis throughout the induction period 3.

Transition Planning

When to Consider Maintenance Therapy

• For AAV: transition to maintenance therapy after completing 3-6 months of induction, not based on creatinine level alone 1.
• For lupus nephritis: transition after 6 months of induction therapy if achieving at least partial remission 1.
• For FSGS: transition after achieving remission or after 16 weeks of high-dose glucocorticoids, whichever comes first 1.

Maintenance Regimen Selection

• For AAV, maintenance options include rituximab (preferred), azathioprine with low-dose glucocorticoids, or mycophenolate mofetil 1.
• For lupus nephritis, mycophenolate mofetil 1-2 g/day with prednisone <5-7.5 mg/day is first-line maintenance 1.
• Maintenance therapy duration should be 18-48 months for AAV and at least 36 months total (induction plus maintenance) for lupus nephritis 1.