Immunotherapy Fails to Boost Small Cell Lung Cancer Survival

Twice-daily radiation therapy may improve outcomes, study finds

Mar. 13, 2026 at 1:14am

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A clinical trial led by NRG Oncology in collaboration with the Alliance for Clinical Trials in Oncology found that adding the immunotherapy agent atezolizumab to chemoradiation did not significantly improve survival for patients with limited-stage small-cell lung cancer (SCLC). However, the study did find that twice-daily radiation therapy was associated with improved survival in this population.

Why it matters

While immunotherapy has improved treatment for extensive-stage SCLC, it remained unknown whether moving immunotherapy into earlier, potentially curable stages would offer benefit. This study provides important insights into the role of immunotherapy and radiation therapy in the management of limited-stage SCLC.

The details

The LU005 study enrolled 544 patients between May 2019 and December 2023 across 218 sites in the U.S. and Japan. Participants were assigned to receive either standard concurrent chemoradiation alone or chemoradiation plus atezolizumab. Thoracic radiation was delivered using either a twice-daily or once-daily schedule. The addition of atezolizumab did not improve progression-free or overall survival. However, the study found that twice-daily radiation therapy was associated with substantially better survival than once-daily radiation, regardless of immunotherapy use.

  • The LU005 study enrolled patients between May 2019 and December 2023.
  • The results of the study are published in the Journal of Clinical Oncology.

The players

NRG Oncology

A National Cancer Institute-supported cooperative group that conducts clinical trials in oncology.

Alliance for Clinical Trials in Oncology

A national clinical trials network that conducts studies in a variety of cancer types.

Helen J. Ross, MD

Professor of Medicine and Director of Research and Clinical Trials at Rush Cancer Center in Chicago, who served as co-principal investigator of LU005 and the Alliance lead investigator.

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What they’re saying

“We are still learning how best to use immunotherapy in limited-stage, small-cell lung cancer. Concurrent immunotherapy with chemoradiotherapy did not improve survival, but we did not find worsened outcomes or unexpected safety signals.”

— Helen J. Ross, MD, Professor of Medicine and Director of Research and Clinical Trials at Rush Cancer Center in Chicago (Journal of Clinical Oncology)

“Radiation was given either once or twice daily based on investigator's choice. Although not randomized, our analysis of the radiation fractionation schedule provides indirect evidence that twice-daily radiation therapy may make a difference in outcomes.”

— Helen J. Ross, MD, Professor of Medicine and Director of Research and Clinical Trials at Rush Cancer Center in Chicago (Journal of Clinical Oncology)

What’s next

The study findings suggest that further research is needed to determine the optimal use of immunotherapy and radiation therapy in the management of limited-stage small-cell lung cancer.

The takeaway

While the addition of immunotherapy did not improve survival in this study, the findings highlight the potential benefits of twice-daily radiation therapy for patients with limited-stage small-cell lung cancer, a regimen that remains underutilized in clinical practice.