Cancer immunotherapy-specific response criteria not only provide improved estimates of treatment response versus standard criteria, but may also better identify patients who achieve an overall survival benefit from therapy.
Compared to standard Response Evaluation Criteria In Solid Tumors (RECIST) v1.1, the immune-modified RECIST provided a 1%-2% greater overall response and an 8%-13% greater rate of disease control, and added 0.5-1.5 months to median progression-free survival among patients treated with the PD-L1 inhibitor atezolizumab, according to analyses of different phase 1 and 2 trials.
In addition, overall survival (OS) benefit in some of the trials could be better delineated using the immune-modified criteria, which account for unique patterns of progression sometimes experienced by patients on cancer immunotherapy, noted the study authors. The report was published in the Journal of Clinical Oncology.
Using immune-specific criteria to evaluate response to cancer immunotherapy is not a new concept. However, there are only limited data on how those criteria might apply to predictions of OS, according to lead author F. Stephen Hodi, MD, of Dana-Farber Cancer Institute, Boston, and his coauthors.
“These analyses reveal aspects of immune-modified RECIST that seem to predict OS better than RECIST v1.1, and aspects needing refinement to improve the ability to predict clinical benefit,” wrote Dr. Hodi and his colleagues.
Typical response criteria may not adequately predict the potential OS benefit of cancer immunotherapy, since patients receiving cancer immunotherapy may exhibit response patterns outside of the “classic response patterns” seen with other anticancer treatments, they noted.
In particular, some patients may experience an initial transient increase in tumor burden before responding, while in other cases, patients with responding baseline lesions might develop new lesions.
Immune-modified criteria have been developed to account for those “other patterns” that can manifest with cancer immunotherapy, the authors said.
Dr. Hodi and his colleagues sought to evaluate outcomes by RECIST vs. immune-related RECIST criteria among patients treated with atezolizumab in studies of non–small-cell lung cancer (NSCLC) and metastatic urothelial carcinoma.
In the phase 2 BIRCH study of first-line atezolizumab for NSCLC, they found that immune-related RECIST criteria appeared to predict OS better than RECIST. Median overall survival was 4.0 months longer among patients who had progressive disease (PD) by RECIST criteria within 90 days of study enrollment, versus patients who had PD by both RECIST and immune-modified RECIST at that time point, Dr. Hodi and his colleagues reported.
In the POPLAR trial of atezolizumab in NSCLC, median overall survival was 1.4 months longer for patients with PD by RECIST vs. patients with PD by both RECIST and immune-modified RECIST at 90 days, they reported.
For patients with metastatic urothelial bladder cancer treated with atezolizumab in the IMvigor210 study, median overall survival was 4.4 months longer for patients with PD by RECIST only vs. PD by both RECIST and immune-related RECIST within 180 days of enrollment, the researchers noted.
An international effort is underway to compare data sets from larger trial sets and multiple cancer immunotherapy agents, they wrote.
SOURCE: Hodi FS et al., J Clin Oncol. 2018 Jan 17. doi: 10.1200/JCO.2017.75.1644