Trial results for the Phase 3 study investigating the addition of atezolizumab to chemoradiation for limited stage small cell lung cancer (LS-SCLC) were posted on ClinicalTrials.gov on 2025-06-12. The study found that the median overall survival for patients receiving atezolizumab plus chemoradiation was 31.1 months, compared to 36.1 months for those receiving chemoradiation alone, with a hazard ratio of 1.05 (95% CI: 0.82 to 1.34) and a p-value of 0.5819.
Background
The trial investigated atezolizumab, an immunotherapy drug, in combination with standard chemoradiation therapy for patients with limited stage small cell lung cancer (LS-SCLC). The study aimed to determine if adding atezolizumab could improve outcomes for this patient population.
Trial design
The study, NCT03811002, was a Phase 3 trial that enrolled 544 participants. It investigated the addition of atezolizumab to usual chemoradiation therapy (CRT) for patients with Limited Stage Small Cell Lung Cancer, including those with Stage I, II, or III disease according to AJCC v8. The interventions included atezolizumab, carboplatin, cisplatin, and etoposide. The trial compared an arm receiving chemotherapy and radiation therapy (Arm I) against an arm receiving chemotherapy, radiation therapy, and atezolizumab (Arm II). The primary outcomes were not explicitly listed in the posted results.
Key results
The trial's key measurements included Overall Survival (OS) and Progression Free Survival (PFS), along with adverse event reporting.
For Overall Survival:
- In Arm I (Chemotherapy, Radiation Therapy), the median Overall Survival was 36.1 months.
- In Arm II (Chemotherapy, Radiation Therapy, Atezolizumab), the median Overall Survival was 31.1 months.
A Log Rank analysis for Overall Survival yielded a Hazard Ratio (HR) of 1.05 (95% Confidence Interval: 0.82 to 1.34) with a p-value of 0.5819.
For Progression Free Survival (PFS):
- In Arm I (Chemotherapy, Radiation Therapy), the median Progression Free Survival was 11.4 months.
- In Arm II (Chemotherapy, Radiation Therapy, Atezolizumab), the median Progression Free Survival was 12.1 months.
A Log Rank analysis for Progression Free Survival yielded a Hazard Ratio (HR) of 0.98 (95% Confidence Interval: 0.8 to 1.21).
Regarding adverse events, the number of participants by highest grade adverse event reported showed:
- For Arm I (Chemotherapy, Radiation Therapy), counts were 4, 3, 8, and 56 participants for various highest grade adverse events.
- For Arm II (Chemotherapy, Radiation Therapy, Atezolizumab), counts were 0, 0, 9, and 63 participants for various highest grade adverse events.
What this means
The trial results indicate that the addition of atezolizumab to standard chemoradiation therapy did not demonstrate a statistically significant improvement in overall survival for patients with limited stage small cell lung cancer. The median overall survival was numerically shorter in the atezolizumab arm compared to chemoradiation alone. While a slight numerical increase in median progression-free survival was observed with atezolizumab, this difference was not statistically significant. These findings suggest that the tested combination did not provide an added survival benefit in this patient population based on the reported data.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03811002, titled 'Testing the Addition of a New Immunotherapy Drug, Atezolizumab (MPDL3280A), to the Usual Chemoradiation (CRT) Therapy Treatment for Limited Stage Small Cell Lung Cancer (LS-SCLC),' were posted on 2025-06-12 on clinicaltrials.gov.