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Background: This study assesses different technologies for detecting epidermal growth factor receptor (EGFR) mutations from circulating tumor DNA in patients with EGFR T790M-positive advanced non-small cell lung cancer (NSCLC) from the AURA3 study (NCT02151981), and it evaluates clinical responses to osimertinib and platinum-pemetrexed according to the plasma T790M status., Methods: Tumor tissue biopsy samples were tested for T790M during screening with the cobas EGFR Mutation Test (cobas tissue). Plasma samples were collected at screening and at the baseline and were retrospectively analyzed for EGFR mutations with the cobas EGFR Mutation Test v2 (cobas plasma), droplet digital polymerase chain reaction (ddPCR; Biodesix), and next-generation sequencing (NGS; Guardant360, Guardant Health)., Results: With cobas tissue test results as a reference, the plasma T790M positive percent agreement (PPA) was 51% (110 of 215 samples) by cobas plasma, 58% (110 of 189) by ddPCR, and 66% (136 of 207) by NGS. Plasma T790M detection was associated with a larger median baseline tumor size (56 mm for T790M-positive vs 39 mm for T790M-negative; P < .0001) and the presence of extrathoracic disease (58% for M1b-positive vs 39% for M0-1a-positive; P = .002). Progression-free survival (PFS) was prolonged in randomized patients (tissue T790M-positive) with a T790M-negative cobas plasma result in comparison with those with a T790M-positive plasma result in both osimertinib (median, 12.5 vs 8.3 months) and platinum-pemetrexed groups (median, 5.6 vs 4.2 months)., Conclusions: PPA was similar between ddPCR and NGS assays; both were more sensitive than cobas plasma. All 3 test platforms are suitable for routine clinical practice. In patients with tissue T790M-positive NSCLC, an absence of detectable plasma T790M at the baseline is associated with longer PFS, which may be attributed to a lower disease burden., (© 2019 American Cancer Society.)

Introduction: Osimertinib is a third-generation EGFR-tyrosine kinase inhibitor (TKI). Durvalumab is an anti-programmed death ligand 1 monoclonal antibody. The phase III open-label CAURAL trial (NCT02454933) investigated osimertinib plus durvalumab versus osimertinib monotherapy in patients with EGFR-TKI sensitizing and EGFR T790M mutation-positive advanced NSCLC and disease progression after EGFR-TKI therapy., Methods: Patients were randomly assigned 1:1 to receive orally administered osimertinib (80 mg once daily) with or without durvalumab (10 mg/kg administered intravenously every 2 weeks) until progression. Treatment could continue beyond progression, providing clinical benefit continued (judged by the investigator). The amended primary objective was to assess the safety and tolerability of osimertinib plus durvalumab; efficacy was an exploratory objective., Results: CAURAL recruitment was terminated early because of increased incidence of interstitial lung disease-like events in the osimertinib plus durvalumab arm from the separate phase Ib TATTON trial (NCT02143466). At termination of CAURAL recruitment, 15 patients had been randomly assigned to treatment with osimertinib and 14 to treatment with osimertinib plus durvalumab. The most common AEs were diarrhea (53% [grade ≥3 in 6% of patients]) in the osimertinib arm and rash (67% [grade ≥3 in 0 patients]) in the combination arm. One patient who had been randomized to the combination arm reported grade 2 interstitial lung disease while receiving osimertinib monotherapy (after discontinuing durvalumab therapy after one dose). The objective response rates were 80% in the osimertinib arm and 64% in the combination arm., Conclusion: Limited patient numbers preclude formal safety and efficacy comparisons between the two treatment arms. The combination of programmed cell death 1/programmed death ligand 1 inhibitors and EGFR-TKIs as therapy for NSCLC is not well understood, but it requires a careful approach if considered in the future., (Copyright © 2019 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

5-Fluorouracil, usually in combination with folinic acid, is widely used in the treatment of both colorectal and head and neck squamous cell cancer patients. Since 5-fluorouracil plus folinic acid and the antifolate thymidylate synthase inhibitor; raltitrexed have distinct mechanisms of action and toxicity profiles, we have evaluated the potential synergistic antitumor interaction between these two agents combined with a sequential schedule of administration in KB (wt-p53) and Cal27 (mut-p53) head and neck squamous cell carcinomas, and LoVo (wt-p53) and HT29 (mut-p53) colorectal cell lines. The combination between a 24-h exposure to raltitrexed followed by a 4-h exposure to 5-fluorouracil plus folinic acid was globally synergistic, as assessed by the median effect principle and combination index. A specific contribution of folinic acid to the cytotoxic effect of the raltitrexed/5-fluorouracil combination was clearly demonstrated by the evaluation of the potentiation factor. In all cell lines, a 1.5- up to 17-fold reduction in the IC50 of both raltitrexed and 5-fluorouracil plus folinic acid was observed in the combination setting compared with the concentrations of the each drug used alone. Moreover, we demonstrated that raltitrexed/5-fluorouracil plus folinic acid induced a distinct S-phase block of the cell cycle, as well as a potentiation of the apoptotic cell death, compared with 5-fluorouracil plus folinic acid or raltitrexed/5-fluorouracil combination. This preclinical work represents, at least to our knowledge, the first demonstration of a synergistic interaction between raltitrexed and 5-fluorouracil modulated by folinic acid, and could represent a rationale for further clinical investigation of raltitrexed/5-fluorouracil plus folinic acid combination.