Current Landscape of Checkpoint Inhibitors in SCLC

Ariel Lopez-Chavez, MD, medical oncologist, director of precision medicine and developmental therapeutics at Allegheny Health Network Cancer Institute, discusses the efficacy of immunotherapy for the potential treatment of extensive-stage small cell lung cancers. In addition, he explains what factors predict response or resistance to these treatments.

According to Lopez-Chavez, 2 checkpoint inhibitors, atezolizumab (Tecentriq) and durvalumab (Imfinzi), have received approvals for use in advanced cancer treatment, based on the IMpower133 (NCT02763579) and CASPIAN trials (NCT03043872). Both drugs have shown effectiveness, including an improvement in median overall survival of 2 to 3 months compared with standard chemotherapy.

However, there are currently no validated biomarkers to predict patient response to these therapies. Although there were initial hypotheses suggesting that tumor mutational burden and PD-L1 expression might serve as predictive markers, these have not been confirmed. Therefore, Lopez-Chavez explains that community oncologists should be aware that while these checkpoint inhibitors are valuable options, patient response cannot be reliably predicted at this time.

Transcription:

0:09 | We have the approvals of 2 checkpoint inhibitors in this space. First is atezolizumab, which received approval based on the results of the IMpower133 trial. The second is durvalumab, also gaining approval based on the results of the CASPIAN trial. Both have demonstrated effectiveness, with hazard ratios ranging from 0.73 to 0.77, indicating their value in this area. Additionally, there is an improvement in median overall survival of two to three months compared [with] standard chemotherapy.

0:54 | Unfortunately, we do not have any factors that predict response to therapy. At the beginning of the trial designs, there were discussions and hypotheses about tumor mutational burden possibly being a predictive marker, or PD-L1 expression being another candidate. However, these have not been validated as markers. So far, we lack any validated markers of response to these therapies in the extensive-stage setting.