What are the latest updates in the treatment of small‑cell lung cancer (SCLC), including first‑line platinum‑etoposide chemotherapy combined with PD‑L1 inhibitors (atezolizumab, durvalumab), concurrent chemoradiation for limited‑stage disease, second‑line options such as topotecan and lurbinectedin, and the role of prophylactic cranial irradiation?

Latest Updates in Small-Cell Lung Cancer Treatment

The most significant recent advance in SCLC treatment is the FDA approval of tarlatamab, a bispecific T-cell engager, for relapsed disease after at least two prior systemic regimens, demonstrating a 40% overall response rate with a remarkably durable 9.7-month median duration of response. 1

First-Line Treatment for Extensive-Stage SCLC

Platinum-etoposide chemotherapy combined with PD-L1 inhibitors (atezolizumab or durvalumab) is now the standard of care for treatment-naïve extensive-stage SCLC in patients with performance status (PS) 0-1 and no contraindications to immunotherapy. 1

• Both atezolizumab and durvalumab combined with carboplatin-etoposide have demonstrated significant overall survival benefit compared to chemotherapy alone 1
• Atezolizumab plus carboplatin-etoposide showed median OS of 12.3 months versus 10.3 months with chemotherapy alone (HR 0.70, P=0.007) 2
• The treatment regimen consists of four 21-day cycles of platinum-etoposide with immunotherapy, followed by maintenance immunotherapy until disease progression or unacceptable toxicity 1
• For immunotherapy-ineligible patients, four to six cycles of platinum plus etoposide remains the preferred first-line treatment 1
• Carboplatin can be substituted for cisplatin, though cisplatin may be preferred in selected younger patients considering toxicity profiles 1

Limited-Stage SCLC: Consolidation Immunotherapy

A major 2025 update establishes that patients with limited-stage SCLC who complete concurrent chemoradiotherapy without disease progression should be offered consolidation durvalumab for up to 2 years if there are no contraindications to immunotherapy. 1

• This represents a paradigm shift in limited-stage disease management, extending the immunotherapy benefit seen in extensive-stage disease 1
• Even patients with ECOG PS 3-4 due to SCLC may be offered consolidation durvalumab if their performance status improves after concurrent or sequential chemoradiotherapy 1
• The standard concurrent chemoradiotherapy approach remains four to six cycles of cisplatin-etoposide with thoracic radiotherapy at 45 Gy twice daily in 30 fractions 1
• Thoracic radiotherapy should be initiated as early as possible, starting on the first or second cycle of chemotherapy 1

Second-Line and Relapsed Disease: Three FDA-Approved Options

For relapsed SCLC with chemotherapy-free interval <90 days (platinum-resistant), single-agent therapy with topotecan, lurbinectedin, or tarlatamab is preferred over multiagent regimens due to better risk-benefit balance. 1

Tarlatamab (Most Recent Approval)

• Approved for patients with disease progression after at least two previous systemic regimens, one of which must have been platinum-based 1
• The 10 mg dose (FDA-recommended) achieved 40% overall response rate with median duration of response of 9.7 months 1
• Response rate was 52% in platinum-resistant disease and 31% in platinum-sensitive disease 1
• Median PFS was 4.9 months, with 9-month OS rate of 68% 1
• Dosing regimen: 1 mg IV on day 1 of cycle 1, then 10 mg on days 8 and 15 of cycle 1, then 10 mg every 2 weeks thereafter 1
• Requires 24-hour inpatient monitoring after the first two doses of cycle 1 (days 1 and 8) due to risk of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) 1
• CRS occurred in 51% of patients (mostly grade 1-2, only 1% grade 3), with median onset of 13 hours and median duration of 4 days, nearly all during first cycle 1
• ICANS occurred in 8% of patients (all grade 1-2), with median onset of 5 days, mostly during cycle 1 1

Lurbinectedin

• Approved for patients progressing on or after first-line platinum-based chemotherapy 1
• Demonstrates 35% overall response rate with median PFS of 3.7 months 3
• Cross-trial comparisons suggest lurbinectedin is more effective than topotecan, though direct comparative data are lacking 1

Topotecan

• Available in both oral and intravenous formulations for platinum-resistant or platinum-sensitive relapse 1
• Cyclophosphamide, doxorubicin, and vincristine (CAV) is an alternative option 1

Platinum Rechallenge

• For patients with chemotherapy-free interval ≥90 days (platinum-sensitive), rechallenge with platinum-based regimen or single-agent systemic therapy may be offered 1

Prophylactic Cranial Irradiation (PCI)

For limited-stage SCLC patients with response after chemoradiotherapy and PS 0-1, PCI should be offered at 25 Gy in 10 fractions. 1

• PCI can be considered in patients with PS 2 1
• The role of PCI is less well defined in patients with stage I-II SCLC or those >70 years of age or who are frail; shared decision-making is recommended in these cases 1
• For extensive-stage SCLC patients <75 years of age with PS 0-2 who achieved response after chemotherapy, PCI (20 Gy/5 fractions or 25 Gy/10 fractions) is justified 1
• In extensive-stage SCLC patients without brain metastases on brain MRI after chemotherapy who can be followed with regular brain MRI, PCI may be omitted 1
• The role of PCI in combination with immunotherapy is not well defined due to paucity of data; treatment may be considered following shared decision-making 1

Consolidative Thoracic Radiotherapy in Extensive-Stage Disease

• For extensive-stage SCLC patients achieving response after chemotherapy with PS 0-2, radiotherapy to residual primary tumor and lymph nodes (30 Gy in 10 fractions) is a treatment option 1

Key Clinical Pitfalls and Caveats

• No validated biomarkers exist for treatment selection in SCLC 1; exploratory analyses show treatment benefit from immunotherapy independent of PD-L1 or blood-based tumor mutational burden status 4
• The DeLLphi-304 trial comparing tarlatamab with standard chemotherapy in relapsed SCLC is ongoing to determine optimal sequencing of second-line agents 1
• Patients with platinum-refractory SCLC have poor prognosis; participation in clinical trials or best supportive care is recommended 1
• Despite initial response rates of 60-70% with platinum-etoposide and immunotherapy, median OS for extensive-stage SCLC remains approximately 12-13 months, with 60% of patients relapsing within 3 months 3
• Three-year overall survival is approximately 56.5% for limited-stage SCLC and 17.6% for extensive-stage SCLC 3