Is atezolizumab (Tecentriq) or durvalumab (Imfinzi) a better option for immunotherapy in extensive stage Small Cell Lung Cancer?

Durvalumab (Imfinzi) is Superior to Atezolizumab (Tecentriq) for Immunotherapy in Extensive-Stage SCLC

Based on the most recent evidence, durvalumab (Imfinzi) is the superior choice over atezolizumab (Tecentriq) for immunotherapy in extensive-stage small cell lung cancer (ES-SCLC), with better overall survival outcomes and potentially fewer immune-related adverse events. 1

Comparison of Efficacy

Both immunotherapy agents have demonstrated significant survival benefits when combined with platinum-based chemotherapy compared to chemotherapy alone:

• Durvalumab (Imfinzi):

  • Median overall survival (OS): 13.0 months (95% CI, 11.5-14.8) vs. 10.3 months with chemotherapy alone 2
  • Hazard ratio for death: 0.73 (95% CI, 0.59-0.91; P=0.0047)
  • 1-year OS rate: 52.8% vs. 39.3% with chemotherapy alone 2
  • Can be combined with either carboplatin or cisplatin plus etoposide 2

• Atezolizumab (Tecentriq):

  • Median overall survival: 12.3 months (95% CI, 10.8-15.8) vs. 10.3 months with chemotherapy alone 2, 3
  • Hazard ratio for death: 0.76 (95% CI, 0.6-0.95; P=0.0154)
  • 1-year OS rate: 51.9% vs. 39.0% with chemotherapy alone 2
  • Typically combined with carboplatin plus etoposide 2

Head-to-Head Comparison

The most recent real-world retrospective study (2024) directly comparing these agents showed:

• Superior overall survival with durvalumab: 14.7 months vs. 11.6 months with atezolizumab (HR 0.59; 95% CI, 0.38-0.92; P=0.020) 1
• No statistically significant difference in progression-free survival (6.3 vs. 5.9 months, P=0.344) 1
• Numerically lower incidence of immune-related adverse events with durvalumab (32.7% vs. 47.8%, P=0.157) 1
• Lower hospitalization rates for immune-related adverse events with durvalumab (16.7% vs. 36.4%, P=0.204) 1

Treatment Recommendations

The NCCN SCLC Panel recommends both regimens as category 1 preferred first-line systemic therapy options for ES-SCLC 2:

1. Durvalumab plus etoposide plus (carboplatin or cisplatin) followed by maintenance durvalumab
2. Carboplatin plus etoposide plus atezolizumab followed by maintenance atezolizumab

Clinical Considerations

• Flexibility with platinum agent: Durvalumab can be combined with either carboplatin or cisplatin (78% of patients in the CASPIAN trial received carboplatin) 2
• Dosing considerations: For atezolizumab, the category 1 recommendation is only for the regimen with 1,200 mg of maintenance atezolizumab, though 1,680 mg is also FDA-approved 2
• Safety profiles: Both agents have similar rates of serious adverse events in clinical trials (32% vs. 36% for durvalumab vs. chemotherapy alone; 67.7% vs. 63.3% for atezolizumab vs. chemotherapy alone) 2
• Death rates from adverse events: Similar between durvalumab and chemotherapy alone (2% vs. 1%) 2

Practical Algorithm for Selection

1. First choice: Durvalumab + etoposide + platinum (carboplatin or cisplatin)

   • Better overall survival in head-to-head comparison
   • Potentially fewer immune-related adverse events
   • More flexibility with platinum agent choice

2. Consider atezolizumab instead if:

   • Patient has previously tolerated atezolizumab well for another indication
   • Insurance/access issues with durvalumab
   • Specific contraindication to durvalumab

Important Caveats

• The head-to-head comparison was a retrospective study, not a randomized controlled trial 1
• Both immunotherapy agents are significantly better than chemotherapy alone
• Individual patient factors such as comorbidities, prior immune-related adverse events, and insurance coverage may influence the choice between these agents
• Regular response assessment is critical: CT with contrast of chest/abdomen/pelvis after every 2-3 cycles and at completion of therapy 2
• For patients with brain metastases, brain MRI (preferred) or CT with contrast should be performed after every 2 cycles 2