Non-small-cell lung cancer patients with activating epidermal growth factor receptor (EGFR) mutations typically benefit from EGFR tyrosine kinase inhibitor treatment. However, virtually all patients succumb to acquired EGFR tyrosine kinase inhibitor resistance that occurs via diverse mechanisms. The diversity and unpredictability of EGFR tyrosine kinase inhibitor resistance mechanisms presents a challenge for developing new treatments to overcome EGFR tyrosine kinase inhibitor resistance. Here, we show that Akt activation is a convergent feature of acquired EGFR tyrosine kinase inhibitor resistance, across a spectrum of diverse, established upstream resistance mechanisms. Combined treatment with an EGFR tyrosine kinase inhibitor and Akt inhibitor causes apoptosis and synergistic growth inhibition in multiple EGFR tyrosine kinase inhibitor-resistant non-small-cell lung cancer models. Moreover, phospho-Akt levels are increased in most clinical specimens obtained from EGFR-mutant non-small-cell lung cancer patients with acquired EGFR tyrosine kinase inhibitor resistance. Our findings provide a rationale for clinical trials testing Akt and EGFR inhibitor co-treatment in patients with elevated phospho-Akt levels to therapeutically combat the heterogeneity of EGFR tyrosine kinase inhibitor resistance mechanisms.

Background:When tumour tissue is unavailable, cell-free DNA (cfDNA)can serve as a surrogate for genetic analyses. Because mutated alleles in cfDNA are usually below 1%, next-generation sequencing (NGS)must be narrowed to target only clinically relevant genes. In this proof-of-concept study, we developed a panel to use in ultra-deep sequencing to identify such mutations in cfDNA.Methods:Our panel (‘SiRe') covers 568 mutations in six genes (EGFR, KRAS, NRAS, BRAF, cKIT and PDGFRα)involved in non-small-cell lung cancer (NSCLC), gastrointestinal stromal tumour, colorectal carcinoma and melanoma. We evaluated the panel performance in three steps. First, we analysed its analytical sensitivity on cell line DNA and by using an artificial reference standard with multiple mutations in different genes. Second, we analysed cfDNA from cancer patients at presentation (n=42), treatment response (n=12) and tumour progression (n=11); all patients had paired tumour tissue and cfDNA previously genotyped with a Taqman-derived assay (TDA). Third, we tested blood samples prospectively collected from NSCLC patients (n=79) to assess the performance of SiRe in clinical practice.Results:SiRe had a high analytical performance and a 0.01% lower limit of detection. In the retrospective series, SiRe detected 40 EGFR, 11 KRAS, 1 NRAS and 5 BRAF mutations (96.8% concordance with TDA). In the baseline samples, SiRe had 100% specificity and 79% sensitivity relative to tumour tissue. Finally, in the prospective series, SiRe detected 8.7% (4/46) of EGFR mutations at baseline and 42.9% (9/21) of EGFR p.T790M in patients at tumour progression.Conclusions:SiRe is a feasible NGS panel for cfDNA analysis in clinical practice.

IMPORTANCETherapies targeting the programmed cell death 1 (PD-1) receptor or its ligand (PD-L1), such as the humanized monoclonal antibody durvalumab, have shown durable clinical responses in several tumor types. However, concerns about the safety and feasibility of PD-1/PD-L1 blockade in HIV-1-infected individuals have led to the exclusion of these patients from clinical trials on cancer immunotherapies. OBJECTIVE To evaluate the feasibility and safety of durvalumab treatment in patients with advanced cancer and virologically controlled HIV-1 infection. DESIGN, SETTING, AND PARTICIPANTSThe DURVAST study was a nonrandomized, open-label, phase 2 clinical trial in patients with any solid tumor type in which anti-PD-1 or anti-PD-L1 antibodies have approved indications or for which there are data of antitumoral activity with no other available curative therapy. All patients had basal undetectable plasma viremia while undergoing combination antiretroviral therapy.INTERVENTIONS Treatment consisted of intravenous infusion of durvalumab (1500 mg every 4 weeks) until disease progression or unacceptable toxic effects. MAIN OUTCOMES AND MEASURESAdverse events were graded with the use of the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03. Tumor response was evaluated using the Response Evaluation Criteria in Solid Tumors version 1.1.RESULTS A total of 20 HIV-1-infected patients with advanced cancer were enrolled; 16 (80%) were male, the median (range) age was 54 (30-73) years, and 12 (60%) had progressed with previous cancer treatment lines. A median (range) of 4 (1-16) cycles of durvalumab were administered. Drug-related adverse events were observed in 50% of patients, and all were grade 1 and 2 (mainly diarrhea, asthenia, and arthromyalgia). Four of 16 response-evaluable patients (25%) had a partial response. Five patients (31%) had stable disease, including 4 with durable stable disease (disease control rate of 50%). CD4 + and CD8 + T-cell counts and plasma HIV-1 viremia remained stable throughout the study.CONCLUSIONS AND RELEVANCE Durvalumab treatment was feasible and safe in HIV-1-infected patients with cancer receiving combination antiretroviral therapy. HIV-1-infected patients on suppressive antiretroviral therapy with advanced cancer should have access to cancer immunotherapy treatments.

Liquid biopsy analyses are already incorporated in the routine clinical practice in many hospitals and oncology departments worldwide, improving the selection of treatments and monitoring of lung cancer patients. Although they have not yet reached its full potential, liquid biopsy-based tests will soon be as widespread as “standard” biopsies and imaging techniques, offering invaluable diagnostic, prognostic, and predictive information. This review summarizes the techniques available for the isolation and analysis of circulating free DNA and RNA, exosomes, tumor-educated platelets, and circulating tumor cells from the blood of cancer patients, presents the methodological challenges associated with each of these materials, and discusses the clinical applications of liquid biopsy testing in lung cancer.

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