Posted: Monday, September 19, 2022
According to a subgroup analysis of the PEARLS/KEYNOTE-091 study, presented at the European Society for Medical Oncology (ESMO) Congress 2022 (Abstract 930MO), pembrolizumab treatment may result in improved survival outcomes in some patients with non–small cell lung cancer (NSCLC) who have a tumor proportion score (TPS) of at least 50%. This finding seems to contrast with those from a previous interim analysis of study results, which suggested that pembrolizumab did not provide a significant survival benefit in this patient subgroup despite being associated with improved disease-free survival overall.
“The lack of statistically significant benefit for [pembrolizumab] in the TPS ≥ 50% population at [the second interim analysis] likely results from placebo overperformance in this population and a smaller population size,” noted Solange Peters, MD, PhD, of Lausanne University, Switzerland, and colleagues. “Overall, data support the benefit of [pembrolizumab] for completely resected stage IB–IIIA NSCLC and, if recommended, adjuvant chemotherapy, regardless of PD-L1 expression.”
The study included 1,177 patients who were randomly assigned to receive either 200 mg of pembrolizumab or placebo once every 3 weeks for a total of 18 doses. Overall, 39.5% of patients had a TPS of less than 1%, 32.2% had a score of between 1% and 49%, and 28.3% had a score of at least 50%. Medium- and long-term disease-free survival was associated with pembrolizumab treatment across all three subgroups.
Among the overall patient population, the rate of grade 3 to 5 adverse events was 34.1% versus 25.8% for pembrolizumab and placebo, respectively. In the subpopulation of patients with a TPS of 50% or greater, grade 3 to 5 adverse event rates were 37.8% and 25.0% for the pembrolizumab and placebo groups, respectively.
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