Mutations in the epidermal growth factor receptor (EGFR) gene are the most common targetable genomic drivers of non-small cell lung cancer (NSCLC), occurring in approximately 50% and 10-15% of adenocarcinomas of the lung in Asian and Western populations, respectively. The most common EGFR-activating mutations, the exon 19 deletion and the L858R point mutation occurring in the receptor tyrosine kinase domain, are susceptible to inhibition. The first EGFR tyrosine kinase inhibitors (TKIs) to be evaluated were the reversible first-generation EGFR TKIs, gefitinib and erlotinib, followed by the irreversible second-generation EGFR TKIs, afatinib and dacomitinib. The study of acquired resistance mechanisms to first-and second-generation EGFR TKIs in patients with activating EGFR-mutated NSCLC identified the gatekeeper T790M point mutation, present in over 50% of cases, as the most common mechanism of acquired resistance. The need to overcome this resistance mechanism led to the development of third-generation EGFR TKIs, of which osimertinib is the only one to date with regulatory approval. In this review, we present the clinical context leading to the development of third-generation EGFR TKIs, the mode of action of these inhibitors and the clinical data supporting their use. We review third-generation TKI agents that are approved, in development, and those that failed in clinical trials. Finally, we will touch upon ongoing studies and future directions, such as combination treatment strategies, currently being explored to improve the efficacy of treatment with third-generation EGFR TKIs.

Metagenomics and total RNA sequencing (total RNA-Seq) have the potential to improve the taxonomic identification of diverse microbial communities, which could allow for the incorporation of microbes into routine ecological assessments. However, these target-PCR-free techniques require more testing and optimization. In this study, we processed metagenomics and total RNA-Seq data from a commercially available microbial mock community using 672 data-processing workflows, identified the most accurate data-processing tools, and compared their microbial identification accuracy at equal and increasing sequencing depths. The accuracy of data-processing tools substantially varied among replicates. Total RNA-Seq was more accurate than metagenomics at equal sequencing depths and even at sequencing depths almost one order of magnitude lower than those of metagenomics. We show that while data-processing tools require further exploration, total RNA-Seq might be a favorable alternative to metagenomics for target-PCR-free taxonomic identifications of microbial communities and might enable a substantial reduction in sequencing costs while maintaining accuracy. This could be particularly an advantage for routine ecological assessments, which require cost-effective yet accurate methods, and might allow for the incorporation of microbes into ecological assessments.

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Metagenomics and total RNA sequencing (total RNA-Seq) have the potential to improve the taxonomic identification of diverse microbial communities, which could allow for the incorporation of microbes into routine freshwater assessments. However, these targeted-PCR-free techniques require more testing and optimization. In this study, we processed metagenomics and total RNA-Seq data from a commercially available microbial mock community using 768 data-processing workflows, identified the most accurate data-processing tools, and compared their microbial identification accuracy at equal and increasing sequencing depths. The accuracy of data-processing tools substantially varied among replicates. Total RNA-Seq was more accurate than metagenomics at equal sequencing depths and even at sequencing depths almost one order of magnitude lower than those of metagenomics. We show that while data-processing tools require further exploration, total RNA-Seq might be a favorable alternative to metagenomics for targeted-PCR-free taxonomic identifications of microbial communities and might enable a substantial reduction in sequencing costs while maintaining accuracy. This could be particularly an advantage for routine freshwater assessments, which require cost-effective yet accurate methods, and might allow for the incorporation of microbes into freshwater assessments.

2599 Background: Second mitochondria-derived activator of caspase (SMAC) mimetics regulate apoptosis and modulate NFκB signaling which drives the expression of genes involved in immune and inflammatory responses. In patient (pt) tumors, Debio 1143 increased PD-1/PD-L1 expression and tumor infiltrating lymphocytes. In pre-clinical models, it synergizes in vitro and in vivo with PD1/PD-L1 checkpoint inhibitors (CPIs). Methods: In a phase I study, using a mCRM model, avelumab (10 mg/kg i.v. on D1&15 q4w) was combined with escalating doses of Debio 1143 (100 mg/d to 250 mg/d orally, D1-10 & D15-24 q4w) to define the RP2D. Consenting adult pts with advanced solid tumors, normal organ function, and PS-ECOG = 0-1 were eligible provided none received prior CPI. Dose-limiting toxicities (DLTs), efficacy, safety, PK, PD and biomarkers were assessed. Results: As of DEC’18, 16 pts were treated; M/F: 8/8; ECOG = 0 in 6 (38%); median age = 58 (28-79); 5 pts had NSCLC, 2 MPM, 2 ovarian and 7 had other tumors (n = 1 each). Common AEs were: nausea (69%); fatigue (62%); vomiting (50%); cough, dyspnea, myalgia (44% each); diarrhea, anorexia (38% each); pruritus and constipation (31% each). These were generally grade 1-2, occasionally grade 3. One pt had a DLT at 250 mg/d dose: a grade 3 AST/ALT increase. No treatment-related AEs grade 4 or higher occurred. No dose-relationships for laboratory abnormalities were observed, except for ALT/AST increases, which at 200 mg/d were all grade 1 and asymptomatic. Maximal tolerated dose was not reached and there were no dose reductions. In 15 evaluable pts, 1 PR (NSCLC) and 5 SD (RECIST v1.1) were observed. Tumor shrinkage > 15% was seen in 2 other NSCLC pts. PK showed high interpatient variability and dose-proportional increase. TNFα and IFNγ peaked in plasma following Debio 1143 dose on D1 after 8 hrs, and on D17/22, in a dose-proportional manner. Four pts developed anti-avelumab antibodies. Conclusions: Debio 1143 at 200 mg/d can be safely combined with avelumab. Toxicity was predictable and mild. Clinical activity was observed in NSCLC pts. PK was linear; no drug interaction was suspected. PD and biomarker analysis is ongoing. Expansion at this RP2D is ongoing in NSCLC. Clinical trial information: NCT03270176.