AlΓ­ Duarte, MD
AlΓ­ Duarte, MD

@AliDuarteMD

11 Tweets 8 reads Feb 08, 2025
🚨 Breaking down the REGENCY trial 🚨
A Phase 3 RCT evaluating obinutuzumab (Obi) in lupus nephritis (LN). Let's dive into the study design, key findings, and the dosing regimens! πŸ§΅β¬‡οΈ
1/ πŸ₯ Study Design
πŸ”Ή Adults w/ biopsy-proven active proliferative LN (Class III/IV, w/ or w/o Class V)
πŸ”Ή Randomized 1:1 to Obi + MMF + steroids vs. Placebo + MMF + steroids
πŸ”Ή Primary endpoint: Complete Renal Response (CRR) at Wk 76
πŸ”Ή Key secondary: CRR w/ low prednisone
2/ πŸ’Š MMF Dosing
πŸ”Ή All pts received MMF
βœ”οΈ Started at randomization (if not already on it)
βœ”οΈ Target dose: 2.0–2.5 g/day by Wk 4
βœ”οΈ Maintained through Wk 76
πŸ“Œ No cyclophosphamide (CYC) arm! MMF was the main immunosuppressant.
3/ πŸ’‰ Obinutuzumab Dosing
πŸ”Ή 1000 mg IV at:
βœ”οΈ Day 1
βœ”οΈ Week 2
βœ”οΈ Week 24
βœ”οΈ Week 26
βœ”οΈ Week 52
πŸ“Œ Two Obi arms (differing by a dose at Wk 50) were pooled for analysis.
4/ πŸ₯ Glucocorticoid Dosing (IV + Oral)
πŸ”Ή Pulse IV methylprednisolone (β‰₯250 mg, max 3g in 4 wks pre-trial)
πŸ”Ή Oral prednisone taper:
βœ”οΈ Start: 0.5 mg/kg/day (max 60 mg/day)
βœ”οΈ Taper to ≀7.5 mg/day by Wk 12
βœ”οΈ Maintain 5 mg/day from Wk 24-80
5/ πŸ† Primary Outcome: Obi = Higher Renal Response!
βœ”οΈ CRR at Wk 76
πŸ”Ή Obi: 46.4%
πŸ”Ή Placebo: 33.1%
βœ… +13.4% (p = 0.02)
βœ”οΈ CRR w/ Pred ≀7.5 mg/day
πŸ”Ή Obi: 42.7%
πŸ”Ή Placebo: 30.9%
βœ… +11.9% (p = 0.04)
6/ πŸ“‰ Renal Function Preservation
βœ”οΈ eGFR Change from Baseline to Wk 76
πŸ”Ή Obi: +2.31 mL/min/1.73mΒ²
πŸ”Ή Placebo: βˆ’1.54 mL/min/1.73mΒ²
πŸ“Œ Obi pts had stable kidney function while placebo pts declined!
7/ ⚠️ Safety Profile
πŸ”Ή Serious Adverse Events (SAEs)
βœ”οΈ Obi: 32.4%
βœ”οΈ Placebo: 18.2%
πŸ”Ή Most common SAEs
βœ”οΈ Infections (esp. COVID-19, pneumonia, UTI)
βœ”οΈ Infusion reactions
βœ”οΈ Neutropenia (Obi 12.5% vs. Placebo 3.8%)
8/ ⚠️ Mortality & COVID-19 Risk
πŸ”Ή Deaths
βœ”οΈ Obi: 3 (2 COVID-19, 1 nephrotic syndrome)
βœ”οΈ Placebo: 1 (COVID-19)
πŸ“Œ COVID-19 disproportionately affected Obi pts β†’ underscores need for vaccination in LN!
9/ πŸ” Who Benefited Most?
βœ”οΈ UPCR β‰₯3 g/g at baseline β†’ Greater benefit
βœ”οΈ Low C3/C4 complement levels β†’ More improvement
βœ”οΈ Class IV LN (vs. Class III) β†’ Better response
πŸ“Œ Deep B-cell depletion helps high-risk LN pts!
πŸ”Ÿ Final Takeaways
βœ… Obi improved renal outcomes in active LN
βœ… Steroid-sparing effect (more Obi pts tapered to ≀7.5 mg/day)
βœ… Proteinuria reduction = better long-term kidney survival
βœ… Infections (esp. COVID-19) are a key safety concern

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