SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2023, about 238,340 new cases of lung cancer will be diagnosed and 127,070 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers. Of the three main subtypes of NSCLC, 30% are Squamous Cell Carcinomas (SCC), 40% are Adenocarcinomas and 10% are Large Cell Carcinomas. With changes in the cigarette composition and decline in tobacco consumption over the past several decades, Adenocarcinoma now is the most frequent histologic subtype of lung cancer.
The 5-year survival rate for patients diagnosed with lung cancer in the US is about 25%, which is a significant improvement over the past 5 years, in part due to earlier detection from lung cancer screening, reduction in smoking, advances in diagnostic and surgical procedures, as well as the introduction of new therapies. However, the 5-year survival rate remains significantly lower among communities of color at 20%. Early detection and screening remain an important unmet need, as 44% of lung cancer cases are not found until they are advanced. In the US, only 5.8% of those individuals at high risk were screened in 2021.
Surgical resection is the primary treatment for approximately 30% of patients with NSCLC who present with early Stage (I–IIIA) disease. These patients are often treated with platinum-based adjuvant chemotherapy to decrease the risk of recurrence. Nonetheless, 45-75% of these patients develop recurrent disease. There is therefore an unmet need for this patient population.
KEYTRUDA® (Pembrolizumab) is a fully humanized, Immunoglobulin G4, anti-PD-1, monoclonal antibody, that binds to the PD-1 receptor and blocks its interaction with ligands PD-L1 and PD-L2. By doing so, it unleashes the tumor-specific effector T cells, and is thereby able to undo PD-1 pathway-mediated inhibition of the immune response.
KEYNOTE-091/EORTC-1416-LCG/ETOP-8-15 – PEARLS trial is a multicenter, randomized, triple-blind, placebo-controlled Phase III trial, which compared the efficacy of KEYTRUDA® with placebo, among patients with resected NSCLC. In this study, 1,177 patients with completely resected Stage IB (T2a ≥4 cm), II, or IIIA NSCLC with negative margins, and with tumor tissue available for PD-L1 testing were included. Systematic complete or lobe-specific mediastinal lymph node dissection was recommended. In the least, the subcarinal and 1 lobe-specific lymph node must have been examined. Eligible patients had not received neoadjuvant radiotherapy or chemotherapy, had ECOG PS of 0-1, and adjuvant chemotherapy for up to four cycles was optional. Adjuvant chemotherapy could be considered for those with Stage IB disease and was strongly recommended for those with Stage II and IIIA disease. Patients were randomized (1:1) to receive KEYTRUDA® 200 mg or placebo IV every three weeks and treatment was continued until disease recurrence, unacceptable toxicity, or up to 1 year. Both treatment groups were well balanced. The median patient age was 65 years, majority of patients (68%) were male, approximately 65% of patients had nonsquamous histology, 56% of patients had Stage II disease and 86% of patients had received adjuvant platinum-based chemotherapy following complete resection. Stratification factors included disease stage, receipt of adjuvant chemotherapy, PD-L1 Tumor Proportion Score and geographic region of the world. The median duration of exposure to KEYTRUDA® was 11.7 months and 68% of patients in the KEYTRUDA® group were exposed to KEYTRUDA® for at least 6 months. The dual Primary endpoints were Disease-Free Survival (DFS) in the overall population and in the population with PD-L1 Tumor Proportion Score (TPS) of 50% or greater. An additional efficacy outcome was Overall Survival (OS). The median follow up for this interim analysis was 35.6 months.
The trial met its Primary endpoint, demonstrating a statistically significant improvement in DFS in the overall population. In the overall population, median DFS was 53.6 months in the KEYTRUDA® group versus 42.0 months in the placebo group (HR=0.76; P=0.0014), reducing the risk of disease recurrence or death by 24% versus placebo, regardless of PD-L1 expression. In the PD-L1 TPS of 50% or greater population, median DFS was not reached in either the KEYTRUDA® group or the placebo group. Overall survival Data were not mature.
It was concluded that these data support the benefit of KEYTRUDA® as a new adjuvant immunotherapy treatment option, for early-stage Non Small Cell Lung Cancer following complete resection, and if indicated, adjuvant chemotherapy, regardless of PD-L1 expression.
Pembrolizumab versus placebo as adjuvant therapy for completely resected stage IB-IIIA non-small-cell lung cancer (PEARLS/KEYNOTE-091):an interim analysis of a randomised, triple-blind, phase 3 trial. O’Brien M, Paz-Ares L, Marreaud S, et al. Lancet Oncol. 2022;10:1274-1286.
