Patients with stage IB to IIA non–small cell lung cancer who experienced a pathologic complete response to neoadjuvant nivolumab plus platinum-based doublet chemotherapy experienced a prolonged event-free survival.
A post hoc analysis indicated that treatment with neoadjuvant nivolumab (Opdivo) plus platinum-based doublet chemotherapy resulted in long-lasting event-free survival (EFS) among patients with stage IB to IIA non–small cell lung cancer (NSCLC) who experienced a pathologic complete response following treatment, according to findings from the phase 3 CheckMate 816 trial (NCT02998528).1
Mariano Provencio-Pulla, PhD, head of medical oncology at Hospital Universitario Puerta de Hierro in Madrid, Spain, presented the findings during the 2022 American Society of Clinical Oncology Annual Meeting. CheckMate 816 is the first in-depth assessment of pathological regression and EFS in a phase 3 trial of neoadjuvant immunotherapy, he said.
“Patients who achieve pCR status in the primary tumor had better EFS than those without—93% in patients who achieved pCR vs 58% at 2 years,” Provencio-Pulla said. He added that patients who had major pathologic response (mPR) also experienced an EFS benefit (HR, 0.26; 95% CI, 0.14.-0.50).
Investigators analyzed the association between pCR in the primary tumor only and EFS, as well as whether degree of pathological regression could be predictive for EFS. Major pathologic complete response (mPR) was a secondary end point.
At a median follow-up of 29.5 months, 46 patients in the experimental arm had a pCR compared with 95 who did not. The median EFS for those with a pCR was not reached (NR; 95% CI, 30.6-NR) compared with 27.8 months (95% CI, 20.0-NR) for those who did not have pCR (HR, 0.18; 95% CI, 0.07-0.46).
Similarly, the median EFS was superior among those who had pCR with chemotherapy treatment compared with those who did not (NR vs 26.2 months).
“Certainly, we have known that pCR correlates with EFS, and that has been presented,” said discussant Jyoti Patel, MD, a professor of medicine at Northwestern University and associate vice-chair for clinical research in the Department of Medicine, as well as medical director of thoracic oncology and assistant director for clinical research in the Lurie Cancer Center in Chicago, Illinois. “Although the numbers, even for the patients who reach pCR [with] chemotherapy alone, [are] quite small, clearly, that indicates better outcome.
“But this analysis is commended to help us go beyond such a binary view, and helps us understand whether the amount of pathologic response can be correlated to further stratify what we do for our patients.”
Provencio-Pulla said investigators conducted receiver operating characteristic (ROC) curve analysis as a continuous variable to assess EFS by depth of pathological regression, which was measured by percent of residual volume of tumor (RVT). Depth of pathological regression appeared to be predictive in the experimental arm (area under the curve [AUC], 0.74) but not for chemotherapy (AUC, 0.54).
“The EFS according to RVT categories was 90% at 2 years for patients with RVT 0% to 5%, 60% for patients with RVT 5% to 30%, 57% in patients with RVT 30% to 80%, and 39% in patients with more than 80% RVT,” Provencio-Pulla said.
Investigators also assessed the association between pCR and EFS by baseline disease stage. Among patients with stage IB/II disease, the median EFS was again superior among those who had a pCR compared with those who did not (NR vs 27.8 months). The same was true for those with baseline stage IIIA disease who had a pCR (NR vs 30.2 months). The 2-year EFS rate was 90% vs 56% among patients with stage IB/II disease and 96% vs 59% in those with stage IIIA disease, in favor of patients who had pCR.
As assessed by PD-L1 expression, the 2-year EFS rate was 86% among those who were PD–L1-negative (< 1%) and had pCR vs 47% for those who did not. The median EFS was 30.6 vs 23.4 months, respectively.
For patients who were PD–L1-positive (³ 1%), the 2-year EFS rate was 97% vs 72% in favor of those who had pCR. The median EFS was NR in both groups.
The FDA approved this combination for patients with resectable NSCLC in March 2022 based on results from CheckMate 816.2 Previous data showed the median EFS with nivolumab plus chemotherapy was 31.6 months (95% CI, 30.2-NR) vs 20.8 months (95% CI, 14.0-26.7) with chemotherapy alone (HR, 0.63; 95% CI, 0.45-0.87; P = .0052).3
The nivolumab combination induced a pCR in 24% (95% CI, 18.0%-31.0%) of patients vs 2.2% (95% CI, 0.6% -5.6%) of patients who received chemotherapy alone (estimated treatment difference 21.6; 95% CI, 15.1-28.2; P < .0001). Results from a prespecified interim analysis for overall survival resulted in a HR of 0.57 (95% CI, 0.38-0.87), which did not cross the boundary for statistical significance.
The open-label, multicenter, CheckMate 816 trial enrolled patients with newly diagnosed, resectable, stage IB to IIIA NSCLC who had an ECOG performance status of 0 or 1 and no known sensitizing EGFR mutations or ALK alterations.
A total of 358 participants were randomly assigned to receive 360 mg nivolumab every 3 weeks plus platinum-doublet chemotherapy every 3 weeks for 3 doses, or to chemotherapy alone. Patients then underwent radiologic restaging, went on to undergo surgery within 6 weeks after treatment, went on to receive optional adjuvant chemotherapy with or without radiotherapy, and then entered follow-up.