P2.07-003 Nivolumab for Patients with EGFR Mutation-Positive Non-Small Cell Lung Cancer

Targeting Protein Kinases to Enhance the Response to anti-PD-1/PD-L1 Immunotherapy

The interaction between programmed cell death protein (PD-1) and its ligand (PD-L1) is one of the main pathways used by some tumors to escape the immune response. In recent years, immunotherapies based on the use of antibodies against PD-1/PD-L1 have been postulated as a great promise for cancer treatment, increasing total survival compared to standard therapy in different tumors. Despite the hopefulness of these results, a significant percentage of patients do not respond to such therapy or will end up evolving toward a progressive disease. Besides their role in PD-L1 expression, altered protein kinases in tumor cells can limit the effectiveness of PD-1/PD-L1 blocking therapies at different levels. In this review, we describe the role of kinases that appear most frequently altered in tumor cells and that can be an impediment for the success of immunotherapies as well as the potential utility of protein kinase inhibitors to enhance the response to such treatments.

Developing Ultrasensitive Library-Aliquot-Based Droplet Digital PCR for Detecting T790M in Plasma-Circulating Tumor DNA of Non-small-Cell-Lung-Cancer Patients

A T790M secondary mutation in epidermal-growth-factor receptor (EGFR) is the most well-established EGFR-tyrosine-kinase-inhibitor (TKI) resistance marker in non-small-cell lung cancer (NSCLC). The current methods to rapidly and accurately detect T790M in clinical practice are not satisfactory because of several obstacles, including the unavailability of tumor-tissue rebiopsies and the low DNA copy number of T790M in circulating tumor DNA (ctDNA). Here, we develop library-aliquot-based droplet digital PCR (LAB-ddPCR) to increase detection sensitivity without affecting accuracy. This new LAB-ddPCR method is performed using aliquots of the ctDNA precapture next-generation-sequencing (NGS) library, in which the isolated ctDNA was amplified and enriched. We show that the LAB-ddPCR can precisely distinguish between T790M wild-type and mutation alleles without introducing extra false-positive signals. In a cohort of 70 post-TKI NSCLC patients, the LAB-ddPCR identified 41 T790M-positive cases (sensitivity 58.57%), but ddPCR only detected T790M in 27 cases (sensitivity 38.57%). Taking the ARMS-PCR result from matched tumor rebiopsies into consideration, the LAB-ddPCR method is better than ddPCR. In conclusion, the LAB-ddPCR ctDNA test offers a feasible and flexible option for the rapid and accurate detection of the T790M secondary mutation, which is helpful in dynamically monitoring drug response and disease progression throughout the therapeutic regimen.