What are the latest updates to small cell lung cancer treatment?

Latest Updates in Small Cell Lung Cancer Treatment

The most significant recent advance is the FDA approval of consolidation durvalumab for up to 2 years after concurrent chemoradiotherapy in limited-stage SCLC, which improves 2-year overall survival by approximately 10%, and the May 2024 FDA approval of tarlatamab for relapsed SCLC after at least two prior systemic regimens. 1

Limited-Stage SCLC: Consolidation Immunotherapy

Patients with limited-stage SCLC who complete concurrent chemoradiotherapy without disease progression should receive consolidation durvalumab for up to 2 years if no contraindications to immunotherapy exist. 1

Key Evidence from ADRIATIC Trial:

• The addition of consolidation durvalumab after chemoradiotherapy increases 2-year overall survival from 58.5% to approximately 68.5% (a 10% absolute improvement) 1
• This represents a new standard of care established in 2024-2025 1
• Treatment-related grade 3-4 adverse events occurred in 8.8% of durvalumab patients versus 6% with placebo 1
• Immune-related adverse events were reported in 32.1% versus 10.2% with placebo 1
• Drug discontinuation rates were higher with durvalumab (16.4% vs 10.6%) 1

Special Population Considerations:

Patients with ECOG performance status 3-4 due to SCLC who show improvement in performance status after concurrent or sequential chemoradiotherapy may be offered consolidation durvalumab if no contraindications exist. 1

Extensive-Stage SCLC: First-Line Treatment

First-line therapy should consist of carboplatin/etoposide (CE) or cisplatin/etoposide (PE) plus immunotherapy (atezolizumab or durvalumab) followed by maintenance immunotherapy in patients without contraindications. 1

• This recommendation carries high-quality evidence and strong recommendation strength 1
• Carboplatin plus etoposide may substitute for cisplatin-based regimens in patients with contraindications to cisplatin 1
• Chemotherapy should commence immediately and not be delayed until radiotherapy can start 1

Relapsed/Refractory SCLC: Novel Targeted Therapy

Tarlatamab represents a breakthrough FDA-approved option (May 2024) for patients with relapsed SCLC after at least two prior systemic regimens, including one platinum-based regimen. 1

Tarlatamab Efficacy and Safety Profile:

• Bispecific T-cell engager targeting DLL3 (expressed on nearly all SCLC cells) and CD3 (on T cells) 1
• FDA-recommended dose: 10 mg every 2 weeks 1
• Overall response rate: 40% with median duration of response 9.7 months 1
• Response rates: 31% in platinum-sensitive disease, 52% in platinum-resistant disease 1
• Median progression-free survival: 4.9 months 1
• 9-month PFS and OS rates: 28% and 68%, respectively 1

Critical Safety Considerations for Tarlatamab:

Cytokine release syndrome (CRS) occurred in 51% of patients, predominantly during the first cycle. 1

• Grade distribution: 30% grade 1,20% grade 2,1% grade 3 1
• Most common CRS symptoms: fever (97%), hypotension (20%), hypoxia (17%) 1
• Median onset: 13 hours; median duration: 4 days 1
• Nearly all CRS events occurred during cycle 1 1

Immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 8% of patients, all grade 1-2, with median onset of 5 days, mostly during cycle 1. 1

Exclusion Criteria for Tarlatamab:

Patients with interstitial lung disease, active pneumonitis, history of severe infusion reactions, severe immune-related adverse events, or grade ≥2 pneumonitis from previous immunotherapy should not receive tarlatamab 1

Second-Line Treatment for Relapsed SCLC

Platinum-Resistant Disease (Chemotherapy-Free Interval <90 days):

Single-agent chemotherapy is preferred over multi-agent regimens; topotecan or lurbinectedin are the preferred agents. 1

• This preference reflects concerns about risk-benefit balance with multi-agent chemotherapy 1
• Both topotecan and lurbinectedin have FDA approval for this indication 1
• Evidence quality is moderate with strong recommendation strength 1

Platinum-Sensitive Disease (Chemotherapy-Free Interval >6 months):

Retreatment with platinum plus etoposide is the preferred approach. 2

• Carboplatin plus etoposide rechallenge demonstrated superior progression-free survival (4.7 months vs 2.7 months with topotecan) in a phase 3 trial 3
• Hazard ratio for progression: 0.57 (90% CI 0.41-0.73; p=0.0041) 3
• Immune checkpoint inhibitors should be avoided if progression occurred on this drug class 2

Additional Treatment Considerations

Immunotherapy in Previously Untreated Patients:

Nivolumab and pembrolizumab remain options for patients not previously treated with checkpoint inhibitors 2

Smoking Cessation:

Smoking cessation should be strongly recommended for all patients, as it improves cancer recurrence rates, treatment tolerance and response, and overall survival in both early-stage and advanced lung cancer. 1

Common Pitfalls to Avoid:

• Do not defer chemotherapy until radiotherapy can begin in limited-stage disease 1
• Do not use immune checkpoint inhibitors in patients who progressed on this drug class 2
• Monitor closely for CRS and ICANS during first cycle of tarlatamab, as nearly all events occur during this period 1
• Screen carefully for contraindications to tarlatamab, particularly prior severe immune-related adverse events or active pneumonitis 1