Serplulimab Dosing
Serplulimab is dosed at 4.5 mg/kg intravenously every 3 weeks (Q3W) when combined with chemotherapy, based on the FDA-approved regimen and multiple phase 3 trials. 1, 2, 3
Standard Dosing Regimens
The established dosing for serplulimab across multiple cancer types is:
- 4.5 mg/kg IV every 3 weeks - This is the primary weight-based regimen validated in pivotal trials 1, 2, 3
Alternative Flat-Dosing Options
Recent population pharmacokinetic analyses support transitioning to flat-dose regimens for greater convenience:
- 300 mg IV every 3 weeks (Q3W) - Achieves comparable exposure to 4.5 mg/kg Q3W 4
- 200 mg IV every 2 weeks (Q2W) - Alternative schedule with similar exposure to 3 mg/kg Q2W 4
The flat-dose regimens (300 mg Q3W or 200 mg Q2W) demonstrate less than 25% difference in median steady-state concentrations compared to weight-based dosing across all body weight ranges, with no clinically meaningful impact on efficacy or safety. 4
Clinical Context by Indication
Extensive-Stage Small Cell Lung Cancer (ES-SCLC)
- Serplulimab 4.5 mg/kg IV Q3W combined with carboplatin and etoposide for up to 4 cycles
- Continue serplulimab maintenance until disease progression
- Demonstrated median OS of 15.8 months vs 11.1 months with chemotherapy alone 1
Non-Squamous NSCLC
- Serplulimab 4.5 mg/kg IV Q3W with pemetrexed and carboplatin
- Median PFS of 11.0 months vs 5.6 months with chemotherapy alone 3
Gastric/GEJ Adenocarcinoma (Perioperative Setting)
- Neoadjuvant: 4.5 mg/kg IV Q3W for 3 cycles with SOX chemotherapy
- Adjuvant: Continue serplulimab for up to 17 cycles 2
Important Considerations
Body weight and albumin are the main predictors of serplulimab exposure, but their effects are modest (≤20%) and not clinically meaningful, supporting a unified dosing approach without dose adjustments based on these factors. 4
The flat-dosing strategy offers practical advantages including reduced dosing errors, simplified preparation, and decreased waste, while maintaining therapeutic equivalence across the body weight spectrum (exposure-response analyses showed no meaningful association between exposure levels and clinical outcomes). 4