Researchers used FDG-PET to evaluate the efficacy of an immunotherapy drug in treating non-small cell lung cancer (NSCLC). Results from this phase II trial were presented at the 2016 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging.1
As many as 85% of cases of lung cancer are NSCLC. Patients with NSCLC typically do not respond well to chemotherapy. Given this nonresponsiveness, immunotherapy is becoming an increasingly popular treatment option for these patients.
This study evaluated atezolizumab, an immune checkpoint blockade inhibitor of programmed death 1 (PD-1). By inhibiting PD-1, atezolizumab stops the ability of cancer cells to evade detection by the immune system’s T cells.
FDG-PET allows areas of increased metabolic activity in cells to be seen. This hypermetabolism is characteristic of cancerous growth. Clinicians can also monitor changes in metabolism after administration of atezolizumab.
“This study is the first to prospectively evaluate FDG-PET imaging in a phase II trial of lung cancer patients receiving the novel immune checkpoint inhibitor atezolizumab,” said Jill Fredrickson, PhD, a clinical imaging scientist in the Department of Early Clinical Development at Genentech in San Francisco, California.
“These findings help define the potential role of FDG-PET as a prognostic and predictive biomarker in the treatment of lung cancer with such immunotherapeutics.”
A total of 138 patients with NSCLC from 28 clinical institutions in 5 countries were enrolled in this study. All patients received 1200 mg of atezolizumab, administered in 3-week intervals. Quantitative FDG-PET measured metabolic activity at baseline prior to treatment and after 6 weeks of treatment with atezolizumab.
Results indicated higher baseline tumor metabolic rates predicted poor patient survival. An additional increase in metabolic rate of tumors at 6 weeks was further predictive of lower patient survival.
The authors noted that FDG-PET can be used when chemotherapy or immunotherapy is used to treat NSCLC as FDG-PET can inform clinicians to how well patients are responding to treatment.
1. Fredrickson J, Funke R, Sanabria S, et al. Utility of FDG-PET in immunotherapy: results from a phase II study of NSCLC patients undergoing therapy with the PD-L1 inhibitor, atezolizumab (MPDL3280A). Presentation at: SNMMI 63rd Annual Meeting; June 11-15, 2016, San Diego, CA. Scientific Paper 134.