for non–small cell lung cancer (NSCLC). While there has been some notable progress in this area, we need phase 3 trials that compare the two therapeutic approaches.
Investigators reporting at the 2022 annual meeting of American Society of Clinical Oncology focused primarily on neoadjuvant treatment, which I’ll address here.
Dr. Joan H. Schiller
In the randomized, phase 2 NADIM II clinical trial reported at the meeting, researchers expanded on the results of NADIM published in 2020 in the Lancet Oncology and in May 2022 in the Journal of Clinical Oncology along with CheckMate 816 results published in the New England Journal of Medicine.
In each of these three studies, researchers compared nivolumab plus chemotherapy versus chemotherapy alone (abstract 8501) as a neoadjuvant treatment for resectable stage IIIA NSCLC. In the study reported at ASCO 2022, patients with resectable clinical stage IIIA-B (per American Joint Committee on Cancer 8th edition) NSCLC and no known EGFR/ALK alterations, were randomized to receive preoperative nivolumab plus chemotherapy (paclitaxel and carboplatin; n = 57) or chemotherapy (n = 29) alone followed by surgery.
The primary endpoint was pathological complete response (pCR); secondary endpoints included major pathological response, safety and tolerability, impact on surgical issues such as delayed or canceled surgeries or length of hospital stay, overall survival and progression free survival. The pCR rate was 36.8% in the neoadjuvant nivolumab plus chemotherapy arm and 6.9% in the chemotherapy alone arm. (P = .0068). 25% of patients on the nivolumab plus chemo arm had grade 3-4 adverse events, compared with 10.3% in the control arm. 93% of patients on the nivolumab plus chemo arm underwent definitive surgery whereas 69.0% of the patients on the chemo alone arm had definitive surgery. (P = .008)
What else did we learn about neoadjuvant treatment at the meeting?
Investigators looking at the optimal number of neoadjuvant cycles (abstract 8500) found that three cycles of sintilimab (an investigational PD-1 inhibitor) produced a numerically higher major pathological response rate, compared with two cycles (when given in concert with platinum-doublet chemotherapy). And, neoadjuvant chemoradiotherapy does not result in significant survival benefits when compared with neoadjuvant chemotherapy alone (abstract 8503).
Of course, when it comes to resectable NSCLC, the goal of treatment is to increase the cure rate and improve survival. No randomized studies have reported yet on overall survival, probably because they are too immature. Instead, disease-free survival (DFS) or event-free survival (EFS) are often used as surrogate endpoints. Since none of the studies reported at ASCO reported on DFS or EFS, we need to look elsewhere. CheckMate 816 was a phase 3 study which randomized patients with stages IB-IIIA NSCLC to receive neoadjuvant nivolumab plus platinum-based chemotherapy or neoadjuvant platinum-based chemotherapy alone, followed by resection. The median EFS was 31.6 months with nivolumab plus chemotherapy and 20.8 months with chemotherapy alone (P = .005). The percentage of patients with a pCR was 24.0% and 2.2%, respectively (P < .001).
We all know one has to be careful when doing cross-trial comparisons as these studies differ by the percentage of patients with various stages of disease, the type of immunotherapy and chemotherapy used, etc. However, I think we can agree that neoadjuvant chemoimmunotherapy results in better outcomes than chemotherapy alone.
Of course, resectable NSCLC is, by definition, resectable. And traditionally, resection is followed by adjuvant chemotherapy to eradicate micrometastases. Unfortunately, the current standard of care for completely resected early-stage NSCLC (stage I [tumor ≥ 4 cm] to IIIA) involves adjuvant platinum-based combination chemotherapy which results in only a modest 4%-5% improvement in survival versus observation.
Given these modest results, as in the neoadjuvant space, investigators have looked at the benefit of adding immunotherapy to adjuvant chemotherapy. One such study has been reported. IMpower 010 randomly assigned patients with completely resected stage IB (tumors ≥ 4 cm) to IIIA NSCLC, whose tumor cells expressed at least 1% PD-L1, to receive adjuvant atezolizumab or best supportive care after adjuvant platinum-based chemotherapy. In the stage II-IIIA population whose tumors expressed PD-L1 on 1% or more of tumor cells, 3-year DFS rates were 60% and 48% in the atezolizumab and best supportive care arms, respectively (hazard ratio, 0·66 P =·.0039). In all patients in the stage II-IIIA population, the 3-year DFS rates were 56% in the atezolizumab group and 49% in the best supportive care group, (HR, 0.79; P = .020).
KEYNOTE-091, reported at the 2021 annual meeting of the European Society for Medical Oncology, randomized early-stage NSCLC patients following complete resection and adjuvant chemotherapy to pembrolizumab or placebo. Median DFS for the overall population was 53.6 months for patients in the pembro arm versus 42 months in the placebo arm (HR, 0.76; P = .0014). Interestingly, the benefit was not seen in patients with PD-L1 with at least 50%, where the 18-month DFS rate was 71.7% in the pembro arm and 70.2% in the placebo arm (HR, 0.82; P = .14). Although the contradictory results of PD-L1 as a biomarker is puzzling, I think we can agree that the addition of immunotherapy following adjuvant chemotherapy improves outcomes compared to adjuvant chemotherapy alone.