Dr. Gainor on Subgroup Analyses From the PACIFIC Trial in NSCLC

Justin F. Gainor, MD, director of Targeted Immunotherapy, Massachusetts General Hospital, and assistant professor of medicine, Harvard Medical School, discusses subgroup analyses from the phase III PACIFIC trial in unresectable stage III non—small cell lung cancer (NSCLC).

In addition to looking at the primary endpoints of the trial, it's also important to address key subgroups. In terms of PD-L1 expression, the subgroup with higher PD-L1 expression, which in PACIFIC was defined as ≥25%, tended to have better rates of progression-free survival (PFS) and overall survival. In patients who had lower PD-L1 expression, there was still an improvement in PFS, but not to the same degree, says Gainor. Although these data provide additional context, the standard of care in the United States is durvalumab (Imfinzi) regardless of PD-L1 expression.

Another important subset that did not seem to derive the same degree of benefit were EGFR-mutant patients. In the stage IV setting, EGFR-mutant patients do not derive significant benefits from single-agent immunotherapy. The same appears to be true in this setting, adds Gainor.

Furthermore, investigators did an analysis looking at time to initiation of durvalumab after chemoradiation. Patients who started durvalumab within 14 days had better outcomes compared with those who started after that 14-day time period. However, there are many caveats to the analysis. Therefore, a patient who has not fully recovered yet from chemoradiation within 14 days should not feel obligated to start durvalumab within that time frame, concludes Gainor.