Adjuvant atezolizumab delays recurrence in early-stage NSCLC patients
medwireNews: People with stage II–IIIA non-small-cell lung cancer (NSCLC) derive a significant disease-free survival (DFS) benefit from adjuvant treatment with atezolizumab versus best supportive care (BSC), according to phase 3 trial results.
“IMpower010 is the first global phase 3 trial using an immune checkpoint inhibitor to show a [DFS] outcome” in this patient population, said the presenting author Heather Wakelee (Stanford University, California, USA) at a press conference for the 2021 ASCO Annual Meeting.
In the study, 1005 patients who had received one to four cycles of adjuvant chemotherapy after complete resection of stage IB–IIIA disease were randomly allocated to receive up to 16 cycles of atezolizumab 1200 mg every 3 weeks or BSC. The median follow-up at data cutoff was 32.8 months.
As per the hierarchical statistical testing mandated by the protocol, the researchers initially assessed DFS in participants with stage II–IIIA disease and a tumor cell PD-L1 expression level of at least 1% (using the SP142 assay) and found a significant 34% reduction in the risk for disease recurrence or death with atezolizumab versus BSC.
The median DFS duration was unreached and 35.3 months in the atezolizumab and control groups, respectively, and the DFS rates at 24 months were 74.6% versus 61.0% and at 36 months were 60.0% versus 48.2%.
Atezolizumab treatment also significantly reduced the risk for recurrence or death by 21% relative to BSC among all patients with stage II–IIIA disease, with respective median DFS times of 42.3 and 35.3 months, and 24- and 36-month DFS rates of 70.2% versus 61.6% and 55.7% versus 49.4%, respectively.
Wakelee and colleagues then evaluated the full study population comprising all patients with stage IB–IIIA NSCLC, but although the DFS results again favored the PD-L1 inhibitor (stratified hazard ratio=0.81), the prespecified boundary for statistical significance was not crossed.
“The overall survival data are not yet mature and have not been formally tested” in this interim analysis, commented Wakelee, and added that “[s]afety data for atezolizumab were consistent with its safety profile and no new signals were identified.”
Adverse events (AEs) of grade 3 or 4 occurred in 21.8% of atezolizumab-treated patients and 11.5% of those given BSC. The rate of treatment-related AEs of grade 5 was 0.8% in the atezolizumab group and 18.2% of patients discontinued the PD-L1 inhibitor due to AEs.
“Given the significantly improved DFS outcomes with adjuvant atezolizumab in patients with PD-L1 expression, it is more important than ever to screen certain high-risk people for lung cancer early and detect PD-L1–positive tumors through biomarker testing,” concluded Wakelee.
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