Key messages
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Some immune-checkpoint inhibitor combinations help people with extensive-stage SCLC live longer than standard chemotherapy alone.
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Not all combinations of immunotherapy are equally effective or safe.
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More research is needed on quality of life and long-term treatment effects, and several immune-checkpoint inhibitor combinations are now important first-line treatment options.
This summary is written for people living with extensive-stage small cell lung cancer (SCLC), their families, caregivers, and anyone looking for clear and accessible information about treatment options.
What is extensive-stage small cell lung cancer (extensive-stage SCLC)?
SCLC is a fast-growing type of lung cancer. It is usually divided into two stages: limited and extensive. In extensive-stage disease, cancer has already spread widely in the lungs or to other parts of the body. Most people with extensive-stage SCLC are treated with a combination of chemotherapy drugs, usually platinum and etoposide, often referred to as 'PE chemotherapy'. But cancer often comes back quickly.
Immune-checkpoint inhibitors are a type of cancer treatment that helps the immune system recognise and attack cancer cells. They work differently from chemotherapy and have become important in treating several types of cancer.
What did we want to find out?
We wanted to find out whether combining immune-checkpoint inhibitors with standard chemotherapy improves survival and other outcomes for people with extensive-stage SCLC. We also wanted to know how safe these treatments are and whether they affect quality of life.
What did we do?
We looked for high-quality studies that compared different immune-checkpoint inhibitor treatments with chemotherapy alone in people with extensive-stage SCLC. We combined the results using a method called network meta-analysis (NMA). This method lets us compare many treatments at the same time, even when some treatments were not directly compared in the same study. NMA works by linking results across different trials. For example, if Study 1 compared Treatment A with Treatment B, and Study 2 compared Treatment B with Treatment C, we can estimate how Treatment A might compare with Treatment C — even though they were never tested against each other. This approach helps build a more complete picture of how all treatments compare overall and which options may be more helpful.
What did we find?
We found 14 studies, with 7541 people contributing data on overall survival, the main outcome of interest. Most of the studies tested whether adding immune-checkpoint inhibitors to platinum-etoposide chemotherapy could improve outcomes.
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Among the evaluated regimens, we found the lowest estimated risk of death with platinum-etoposide chemotherapy combined with benmelstobart plus anlotinib or serplulimab, and we also found improvements in survival with durvalumab or adebrelimab.
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Other combinations, such as those including ipilimumab, probably do not improve survival and may increase side effects. Some treatments, including serplulimab or certain combination immunotherapies, were also linked with more side effects than standard chemotherapy.
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For progression-free survival (the time before the cancer gets worse), some treatments delayed cancer worsening, but these effects did not always match improvements in overall survival.
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Only a few treatments improved response rates (shrinking or eliminating tumours), and this did not always match the improvements in survival.
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There was not enough useful information about quality of life to help people and clinicians make informed decisions.
What are the limitations of the evidence?
Some studies included only a small number of people or were conducted in limited regions, which may affect how well the results apply to everyone. Also, not all studies reported results in the same manner. Few studies reported on patient experiences or long-term effects. Because few studies directly compared different immune-checkpoint inhibitor combinations with each other, we need more head-to-head trials to be certain about which treatments work best. People may wish to discuss with their healthcare team how these results apply to their own situation, including side effects, expected benefits, and how treatment may affect day-to-day quality of life.
How up to date is this evidence?
This review includes evidence available up to December 2025.
Read the full abstract
Objectives
To evaluate the comparative benefits and harms of immunotherapy (anti-PD-1, anti-PD-L1, or anti-CTLA-4), plus chemotherapy and other relevant first-line systemic chemotherapy-based regimens, for the first-line systemic treatment of extensive-stage SCLC with a network meta-analysis; to rank the interventions according to their benefits and harms; and to explore the potential role of biomarkers or clinical factors, where data are available.
Search strategy
We used CENTRAL, MEDLINE, and Embase, together with clinical trial registries, to identify studies that were included in the review. The latest search date was 12 December 2025.
Authors' conclusions
In people with extensive-stage SCLC, several ICI-based combinations with PE chemotherapy improve OS compared with PE alone (high-certainty evidence), although the magnitude of benefit varies across regimens. Some combinations probably or may have little to no effect on OS. Effects on PFS and ORR vary across treatments, and some combinations increase the risk of AEs whereas others result in little to no difference. HRQoL data were insufficient for quantitative synthesis, and so we are unable to draw conclusions about this outcome.
The certainty of the evidence varies across outcomes and comparisons, reflecting differences in study design, variability in safety reporting, and limited direct head-to-head comparisons. Further RCTs directly comparing commonly used first-line regimens, with consistent reporting of AEs and patient-reported outcomes including HRQoL, are needed to reduce uncertainty and inform treatment decisions.
Funding
Takeshi Hasegawa and Hisashi Noma were supported by the Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (Grant numbers: 22H03554, 19K03092, 24K06239).
Registration
Protocol available via doi.org/10.1002/14651858.CD015738
