No abstract

Introduction: We evaluated the impact of patient characteristics, sample types, and prior non-immunotherapy treatment on tumor cell (TC) programmed cell death ligand 1 (PD-L1) expression using samples from patients with advanced NSCLC. Methods: Patients (N ¼ 1590) screened for the ATLANTIC study submitted a recently acquired (3 months) or archival (>3 months to >3 years old) tumor sample for PD-L1 assessment using the VENTANA PD-L1 (SP263) Assay with a cutoff of !25% of TCs expressing PD-L1 (TC !25%). Samples were acquired either before or after the two or more treatment regimens required for study entry and sample age varied among patients. A subset of patients (n ¼ 123) provided both recent and archival samples. Results: A total of 517 of 1590 (32.5%) patients had TC greater than or equal to 25%: prevalence was greater in smokers versus nonsmokers (p ¼ 0.0005) and those with EGFRÀ versus EGFRþ tumors (p ¼ 0.0002); these effects were independent. Prevalence of TC greater than or equal to 25% was increased in recent metastatic versus primary (p ¼ 0.005) and recent versus archival (p ¼ 0.039) samples. Chemotherapy or radiotherapy, but not tyrosine kinase inhibition, before sampling was associated with significantly increased PD-L1 prevalence. PD-L1 status (TC !25% cutoff) remained unchanged in 74.0% of patients with recent and archival samples; where PD-L1 status changed, it was more likely to increase than decrease over time or with intervening treatment. Conclusions: Several factors potentially impact PD-L1 TC greater than or equal to 25% prevalence in advanced NSCLC; however, no characteristic can be considered a surrogate for PD-L1 expression. Fresh biopsy may provide more accurate assessment of current tumoral PD-L1 expression where a low/negative result is seen in an archival sample, especially if the patient has received intervening therapy.

Testing for mutations in the KRAS oncogene for patients with metastatic colorectal cancer (mCRC) is generally performed using DNA from formalin-fixed paraffin-embedded tumor tissue; however, access to specimens can be limited and analysis challenging. This study assessed the identification of KRAS mutations in circulating free DNA (cfDNA) using a commercially available KRAS polymerase chain reaction (PCR) kit. Matched plasma, serum and tumor samples were available from 71 patients with mCRC who had received prior therapy but whose disease progressed following therapy. Yields of cfDNA from plasma and serum samples were comparable. Analyses were successful in 70/71 plasma-extracted samples (specificity: 97%, sensitivity: 31%) and 67/71 serum- extracted samples (specificity: 100%, sensitivity: 25%). This study demonstrates that KRAS mutations can be detected in cfDNA using a commercially available KRAS PCR kit, confirming cfDNA as a potential alternative source of tumor DNA in a diagnostic setting if access to archival tumor specimens is limited.

Background and aim "Gain-of-function" mutations in voltage-gated sodium channel NaV1.7 have been linked to erythromelalgia (EM), characterized by painful hot and red hands and feet. We investigated the proportion of patients with EM that carry a mutation in NaV1.7 or in other pain-related genes and studied possible clinical differences. Methods In this study, 48 patients with EM were screened for mutations in a total of 29 candidate genes, including all sodium channel subunits, transient receptor potential channels (TRPA1, TRPV1, TRPM8), neurotrophic factors (NGF, NGFR, BDNF, GDNF, NTRK1 and WNK1) and other known pain-related genes (CACNG2, KCNS1, COMT, P2RX3, TAC1, TACR1), using a combination of next generation sequencing and classical Sanger sequencing. Results In 7/48 patients protein-modifying mutations of NaV1.7 (P187L, I228M, I848T (n = 4) and N1245S) were identified. Patients with the I848T mutation could be identified clinically based on early onset and severity of the disease. In contrast, there were no clinical characteristics that differentiated the other patients with NaV1.7 mutation from those patients without. We also found more than twenty rare protein-modifying genetic variants in the genes coding for sodium channels (NaV1.8, NaV1.9, NaV1.6, NaV1.5, NaV2.1, SCN1B, SCN3B), transient receptor potential channel (TRPA1, TRPV1), and other pain-related targets (WNK1 and NGFR). Conclusion We conclude that functionally characterized mutations of NaV1.7 (I848T) are present only in a minority of patient with EM. Albeit the majority of patients (27/48) carried rare protein-modifying mutations the vast majority of those will most probably not be causally linked to their disease. Implications The key question remaining to be solved is the possible role of rare variants of NaV1.8, NaV1.9, or beta-subunits in provoking chronic pain conditions or even EM.

PURPOSE Biomarkers that predict response to immune checkpoint inhibitors (ICIs) in recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) are needed. This retrospective study assessed tumor mutational burden (TMB) and outcomes in the phase 2 HAWK and CONDOR and phase 3 EAGLE studies of durvalumab with or without tremelimumab in platinum-resistant R/M HNSCC. EXPERIMENTAL DESIGN Tumor samples from HAWK/CONDOR (N=153) and blood samples from EAGLE (N=247) were analyzed for TMB. Associations with survival were evaluated for tissue TMB (tTMB) at cutoffs from 10 to 20 mutations/megabase (mut/Mb) and for plasma TMB (bTMB) at cutoffs from 8 to 24 mut/Mb. RESULTS In HAWK/CONDOR, overall survival (OS) with durvalumab with or without tremelimumab was longer for high versus low tTMB: statistically significant differences were observed with durvalumab plus tremelimumab at tTMB≥10 mut/Mb (hazard ratio [HR], 0.52 [95% CI, 0.28-0.98]) and tTMB≥12 mut/Mb (HR, 0.46 [95% CI, 0.24-0.86]). In EAGLE, a significant OS benefit versus chemotherapy was observed with durvalumab and durvalumab plus tremelimumab at bTMB≥16 mut/Mb (HR, 0.39 [95% CI, 0.20-0.76] and 0.38 [95% CI, 0.19-0.78], respectively) but not bTMB<16 mut/Mb (HR, 0.92 [0.61-1.37] and 0.92 [95% CI, 0.62-1.36], respectively). A significant progression-free survival benefit was also observed in the ICI arms versus chemotherapy at bTMB≥16 mut/Mb. CONCLUSION Findings support TMB as a biomarker for predicting survival in patients with platinum-resistant R/M HNSCC treated with ICIs. The analysis of EAGLE demonstrated that bTMB was predictive of survival with ICI treatment versus chemotherapy in a large, randomized controlled study population.