Real-World Analysis Identifies Clinical Predictors of Long-Term Response and Survival with Atezolizumab Plus Chemotherapy in ES-SCLC: CLINATEZO Study

Key Clinical Summary:

• Design/Population: The CLINATEZO study was a real-world, multicenter retrospective analysis of 517 patients with extensive-stage small cell lung cancer treated with atezolizumab plus platinum-based chemotherapy across 65 centers (May 2019 to March 2020), with median follow-up 53.8 months.
• Key Outcomes: Median real-world PFS was 5.2 months, with 12- and 48-month PFS rates of 14.6% and 6.8%, respectively. Median OS was 11.3 months, with 24- and 48-month OS rates of 21.1% and 11.4%. Long-term responders (n = 65) had a median OS of 53.7 months vs 9.7 months in others, and long-term survivors (n = 106) had a median OS of 52.9 months vs 8.8 months. Predictors of durable benefit included former smoking status, ECOG 0 to 1, younger age, limited-stage disease at diagnosis, and prior platinum exposure.
• Clinical Relevance: Real-world outcomes with atezolizumab plus chemotherapy mirror landmark trial results and identify a distinct subset achieving prolonged survival ( > 4 years). Baseline clinical factors may help risk-stratify patients for durable benefit, informing personalized monitoring and sequencing strategies in ES-SCLC.

In the CLINATEZO study, a real-world retrospective analysis of patients with extensive-stage small cell lung cancer (ES-SCLC) treated with atezolizumab plus platinum-based chemotherapy, long-term responders and survivors were identified, with smoking status and performance status emerging as key predictors of durable benefit.

“Long-term follow-up from the extension study IMbrella A was obtained for only 18 patients. Similarly, long-term follow-up data have not yet been made available from real-world cohorts of patients with SCLC who received chemotherapy and immunotherapy.,” wrote Lionel D, MD, North West Hospital of Villefranche, Gleizé, France, and co-authors. 

Patients received atezolizumab plus chemotherapy. The primary end point was long-term disease control, which was defined as real-world progression-free survival (PFS) longer than 12 months and overall survival (OS) as longer than 24 months. 

Overall, 517 patients treated between May 2019 and March 2020 across 65 centers.  At a median follow-up of 53.8 months (95% confidence interval [CI], 52.8 to 54.7), the median real-world PFS rate was 5.2 (95% CI, 5.0 to 5.4), with 12-month and 48-month real-world PFS rates of 14.6% (95% CI, 11.6 to 17.9) and 6.8% (95%, 4.7 to 9.4), respectively. Median overall survival (OS) was 11.3 months (95% CI, 10.1 to 12.4), with 24-month and 48-month OS rates of 21.1% (95% CI, 17.7 and 24.8) and 11.4% (95% CI, 9.9 to 14.4).

Long-term response was observed in 65 patients. These patients had a markedly prolonged median OS of 53.7 months (95% CI, 39.2 to not reached) compared to 9.7 months (95% CI, 8.8 to 10.6) in those with real-world PFS less than 12 months. Baseline factors associated with long-term response included former smoking status (vs current smoker; P = 0.003) and ECOG performance status 0 to 1 (vs 2; P = 0.048).

Long-term survival was observed in 106 patients, with a median OS of 52.9 months (95% CI, 40.3 to not reached) in this subgroup versus 8.8 months (95% CI, 8.3 to 9.7; P < 0.0001) in those with OS less than 24 months. Predictors of long-term survival included younger age (P = 0.030), limited-stage disease at initial diagnosis (P = 0.022), and prior platinum-based chemotherapy (P = 0.01).

Dr Falchero and co-authors concluded, “long-term follow-up of the the large, real-world CLINATEZO study, shows the reproducibility of the key survival outcomes of landmark trials, and identify a subset of patients with long-term control of the disease and survival for which treatment monitoring and sequencing strategies may be specifically developed.”

Source:

Falchero L, Amrane K, Godbert B, et al. Long-term response and survival in extensive stage small cell lung cancer receiving atezolizumab plus chemotherapy in a real-world setting: IFCT-1905 CLINATEZO. JTO Clinical and Research Reports. Published online January 31, 2026. doi:10.1016/j.jtocrr.2026.100964