Does atezolizumab added to chemotherapy improve survival in patients with small-cell lung cancer?

This article looked at the outcomes of patients with extensive-stage (ES) small cell lung cancer (SCLC) treated with atezolizumab (Tecentriq), carboplatin (CP; Paraplatin), and etoposide (ET; Etopophos). The authors found that the addition of atezolizumab to CP/ET chemotherapy improved the outcomes of these patients. 

SCLC represents around 15% of all lung cancer diagnoses. Around 70% of SCLCs are diagnosed as ES. ES-SCLC is cancer that has spread beyond the lung, to the lymph node, the other lung, or to other parts of the body. ES-SCLC is usually treated effectively with chemotherapy. Despite this, patients usually experience a rapid spread of the cancer. Therefore, new therapies are needed for this type of cancer.

Atezolizumab is an immunotherapy. It targets a protein PD-L1 that can be found on some cancerous cells and shuts down the immune system so they can grow and spread undetected. Blocking PD-L1 restores the capacity of the immune system to attack and kill cancer cells. CP/ET are forms of chemotherapy used in the treatment of SCLC. Previous studies have shown that atezolizumab added to chemotherapy improves the short-term outcomes of patients with ES-SCLC. However, longer-term outcomes of these patients are still unknown.

There were 403 patients with ES-SMLC in this study. 201 patients were randomly assigned to receive atezolizumab plus CP/ET. The other 202 patients received placebo plus CP/ET. The average follow-up was 22.9 months.  

The average overall survival was 12.3 months in the atezolizumab group compared to 10.3 months in the placebo group. After 18 months, 34% of the atezolizumab group were alive compared to 21% of the placebo group. The average survival without cancer worsening was longer in the atezolizumab group (5.2 months) compared to the placebo group (4.3 months).

The benefit from the addition of atezolizumab to CP/ET was similar in patients with different levels of PD-L1. The atezolizumab group experienced a slightly higher rate of immune-related side effects such as skin rash, decreased thyroid function, liver inflammation, or infusion reactions. 

The authors concluded that the addition of atezolizumab to CP/ET chemotherapy improved the outcomes of patients with ES-SCLC.

This article was supported by funding from F. Hoffmann-La Roche Ltd/Genentech, Inc, the manufacturers of atezolizumab.