The addition of atezolizumab to chemotherapy was associated with superior PFS but did not improve preliminary OS.
Adding atezolizumab immunotherapy to chemotherapy is associated with a reduced risk of tumor progression and death among patients with advanced squamous non–small-cell lung cancer (NSCLC), according to initial findings from the randomized phase III IMpower 131 study (ClinicalTrials.gov identifier: NCT02367794; abstract LBA9000). The findings were presented at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting, held June 1–5 in Chicago.
The combination was associated with twice the investigator-assessed 12-month progression-free survival (PFS) rate compared with carboplatin and nab-paclitaxel–based chemotherapy alone (24.7% vs 12.0%; hazard ratio [HR], 0.71; 95% CI, 0.60–0.85; P = .0001), reported lead study author Robert M. Jotte, MD, PhD, of Rocky Mountain Cancer Centers, Denver, Colorado.
“We used to think that chemotherapy just knocked down the patient’s immune system and that it would be irrational to combine it with immunotherapy, but growing research, including this study, shows that chemotherapy can help trigger the immune response to the tumor, helping the immunotherapy treatment to work better,” Jotte said.
Atezolizumab targets programmed death ligand 1 (PD-L1), but patient benefits did not depend on tumor PD-L1 expression, Jotte reported.
Patients received 4 or 6 cycles of chemotherapy with (n = 343) or without atezolizumab (n = 340) until progression.
Nearly all patients experienced treatment-related adverse events (94.6% of those receiving atezolizumab with chemotherapy and 90.7% of those receiving only carboplatin and nab-paclitaxel). Serious toxicities were reported for 20% and 10.5% of patients in the atezolizumab and control groups, respectively.
“The safety profile was consistent with the known risks of the individual treatment components,” Jotte reported. “No new safety signals were identified.”
Confirmed objective response rates were higher and duration of response was longer with atezolizumab plus chemotherapy than with chemotherapy alone, regardless of PD-L1 expression.
Interim overall survival (OS) in the intent-to-treat population was nearly identical between the study arms (14 months vs. 13.9 months in the control group).
“Overall survival continues to be followed, with the next interim OS analysis anticipated late in 2018,” Jotte said.
Jotte disclosed financial relationships with Bristol-Myers Squibb.