Post-meal exercise under ecological conditions improves post-prandial glucose levels but not 24-hour glucose control.

We investigated whether post-meal walking (PMW) improved post-prandial glucose and 24h glucose control under free-living conditions among physically inactive young women. METHODS: Young women (Age: 20±1years; percent body fat: 28.2 ± 12%; BMI: 23.8 ± 4.2kg·m-1) completed a randomised crossover study to assess if PMW confers benefit. On the PMW day, women completed three bouts of brisk walks, and on the Control day they were instructed to follow normal habitual activities. Continuous glucose monitors captured post-prandial and 24h glucose, and physical activity monitors tracked physical activity throughout the study. RESULTS: PMW walking increased total daily step count (Control = 9,159 ± 2,962 steps vs. PMW = 14,611±3,891 steps, p<0.001) and activity scores (Control=33.87±1.16 METs·h vs. PMW = 36.11±1.58 METs·h, p < 0.001). PMW led to lower 3h average post-prandial glucose (main effect of condition, p=0.011) and 3h post-prandial area under curve glucose responses (main effect of condition, p = 0.027) compared to the control condition. Post hoc analysis revealed the largest decline occurred after dinner (3h average glucose Control = 7.55±1.21 mmol/L vs. PMW = 6.71 ± 0.80mmol/L, p = 0.039), when insulin sensitivity is typically diminished. Despite improvements in post-prandial glucose control, this did not translate to improvements in 24h glucose control (p > 0.05). CONCLUSION: Physically inactive and metabolically healthy young women, PMW improves post-prandial glucose but not 24h glucose control.

Overcoming osimertinib resistance with AKT inhibition in EGFRm-driven Non-Small-Cell-Lung-Cancer with PIK3CA/PTEN alterations.

PURPOSE: Osimertinib is an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) indicated for the treatment of EGFR mutated (EGFRm)-driven lung adenocarcinomas. Osimertinib significantly improves progression-free survival in first-line treated patients with EGFRm advanced NSCLC. Despite the durable disease control, the majority of patients receiving osimertinib eventually develop disease progression. EXPERIMENTAL DESIGN: ctDNA profiling analysis on-progression plasma samples from patients treated with osimertinib in both first (Phase 3, FLAURA trial) and second-line trials (Phase 3, AURA3 trial) revealed a high prevalence of PIK3CA/AKT/PTEN alterations. In vitro and in vivo evidence using CRISPR engineered NSCLC cell lines and PXD models support a functional role for PIK3CA and PTEN mutations in the development of osimertinib resistance. RESULTS: These alterations are functionally relevant as EGFRm NSCLC cells with engineered PIK3CA/AKT/PTEN alterations develop resistance to osimertinib and can be re-sensitized by treatment with the combination of osimertinib and the AKT inhibitor capivasertib. Moreover, xenograft and PDX in vivo models with PIK3CA/AKT/PTEN alterations display limited sensitivity to osimertinib relative to models without alteration, and in these double mutant models capivasertib and osimertinib combination elicits an improved anti-tumor effect versus osimertinib alone. CONCLUSIONS: Together, this approach offers a potential treatment strategy for patients with EGFRm-driven NSCLC that have a sub-optimal response, or develop resistance, to osimertinib through PIK3CA/AKT/PTEN alterations.

Genome-wide CRISPR screens identify the YAP/TEAD axis as a driver of persister cells in EGFR mutant lung cancer.

Most lung cancer patients with metastatic cancer eventually relapse with drug-resistant disease following treatment and EGFR mutant lung cancer is no exception. Genome-wide CRISPR screens, to either knock out or overexpress all protein-coding genes in cancer cell lines, revealed the landscape of pathways that cause resistance to the EGFR inhibitors osimertinib or gefitinib in EGFR mutant lung cancer. Among the most recurrent resistance genes were those that regulate the Hippo pathway. Following osimertinib treatment a subpopulation of cancer cells are able to survive and over time develop stable resistance. These 'persister' cells can exploit non-genetic (transcriptional) programs that enable cancer cells to survive drug treatment. Using genetic and pharmacologic tools we identified Hippo signalling as an important non-genetic mechanism of cell survival following osimertinib treatment. Further, we show that combinatorial targeting of the Hippo pathway and EGFR is highly effective in EGFR mutant lung cancer cells and patient-derived organoids, suggesting a new therapeutic strategy for EGFR mutant lung cancer patients.

Utilizing a Dual Human Transporter MDCKII-MDR1-BCRP Cell Line to Assess Efflux at the Blood Brain Barrier.

To facilitate the design of drugs readily able to cross the blood brain barrier (BBB), a Madin-Darby canine kidney (MDCK) cell line was established that over expresses both P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP), the main human efflux transporters of the BBB. Proteomics analyses indicate BCRP is expressed at a higher level than Pgp in this cell line. This cell line shows good activity for both transporters [BCRP substrate dantrolene efflux ratio (ER) 16.3 ± 0.9, Pgp substrate quinidine ER 27.5 ± 1.2], and use of selective transporter inhibitors enables an assessment of the relative contributions to overall ERs. The MDCKII-MDR1-BCRP ER negatively correlates with rat unbound brain/unbound plasma ratio, Kpuu Highly brain penetrant compounds with rat Kpuu ≥ 0.3 show ERs ≤ 2 in the MDCKII-MDR1-BCRP assay while compounds predominantly excluded from the brain, Kpuu ≤ 0.05, demonstrate ERs ≥ 20. A subset of compounds with MDCKII-MDR1-BCRP ER < 2 and rat Kpuu < 0.3 were shown to be substrates of rat Pgp using a rat transfected cell line, MDCKII-rMdr1a. These compounds also showed ERs > 2 in the human National Institutes of Health (NIH) MDCKI-MDR1 (high Pgp expression) cell line, which suggests that they are weak human Pgp substrates. Characterization of 37 drugs targeting the central nervous system in the MDCKII-MDR1-BCRP efflux assay show 36 have ERs < 2. In drug discovery, use of the MDCKII-MDR1-BCRP in parallel with the NIH MDCKI-MDR1 cell line is useful for identification of compounds with high brain penetration. SIGNIFICANCE STATEMENT: A single cell line that includes both the major human efflux transporters of the blood brain barrier (MDCKII-MDR1-BCRP) has been established facilitating the rapid identification of efflux substrates and enabling the design of brain penetrant molecules. Efflux ratios using this cell line demonstrate a clear relationship with brain penetration as defined by rat brain Kpuu.

A study of the impact of the COVID-19 pandemic on equine veterinary care in the UK.

Background: During the COVID-19 pandemic, equine health care in the UK may have been adversely affected due to mandated changes in the delivery of veterinary healthcare and the potential for reduced health-seeking behaviour. Methods: Electronic patient records (EPRs) were analysed to describe veterinary activity for all equids under the active care of 20 veterinary practices in the UK in the 12 months before and after the introduction of the first UK lockdown. Pre-pandemic and pandemic levels of clinical activity were compared. Further comparisons of care, including immediate management and treatment, were made following a detailed review of EPRs from randomly selected subsets of equids under care in four time periods. Results: All measures of activity and face-to-face interaction were lower in the early pandemic period than in the equivalent pre-pandemic period. Compared to pre-pandemic, the early pandemic was associated with a decrease in prophylactic care and non-urgent diagnostic imaging and an increase in systemic non-steroid anti-inflammatory prescription. Convenience sampling of veterinary practices may have limited the generalisability of the findings. The quality of EPRs was variable. Conclusions: While equine veterinary activity was significantly disrupted in the early pandemic period, there was a rapid return to pre-pandemic levels of activity. Subsequent lockdowns appeared to have had little effect on veterinary care.

"Bringing you the best": John Player & Sons, Cricket, and the Politics of Tobacco Sport Sponsorship in Britain, 1969-1986.

This article explores some of the marketing strategies associated with the British tobacco industry's sponsorship of sport during the 1960s and 1970s. It focuses on the British cigarette and tobacco manufacturer John Player & Sons and the firm's pioneering initiative to sponsor one-day cricket, which began with the John Player League in 1969. The league was enormously popular and gained significant broadcast coverage, becoming an invaluable means of increasing public exposure for the company, in the context of the ban of cigarette advertising from British television. At a time when the link between smoking and disease was making headlines, John Player & Sons nimbly deflected attention away from the health issue, and instead consciously repositioned the tobacco company as a generous benefactor of the nation's sport and leisure. Less conspicuously, but even more powerfully, spokespeople for the tobacco industry actively mobilised influential opinion behind the scenes in political circles. We show particularly how Denis Howell, Minister for Sport from 1964 to 1969 and from 1974 to 1979, became a valuable ally, acting as a bulwark against more restrictive government interventions into the sponsorship of sports by the tobacco industry. This alliance exposes changing industry-government relations and presents new historical context to better understand the way British tobacco manufacturers proactively sought to elide restrictions on their advertising activities from the 1980s onwards.

Discovery and Optimization of the First ATP Competitive Type-III c-MET Inhibitor.

Recent clinical reports have highlighted the need for wild-type (WT) and mutant dual inhibitors of c-MET kinase for the treatment of cancer. We report herein a novel chemical series of ATP competitive type-III inhibitors of WT and D1228V mutant c-MET. Using a combination of structure-based drug design and computational analyses, ligand 2 was optimized to a highly selective chemical series with nanomolar activities in biochemical and cellular settings. Representatives of the series demonstrate excellent pharmacokinetic profiles in rat in vivo studies with promising free-brain exposures, paving the way for the design of brain permeable drugs for the treatment of c-MET driven cancers.

Excess adiposity contributes to higher ambulatory central blood pressure and arterial stiffness in physically inactive young adults.

BACKGROUND: It remains unknown if physical inactivity and excess adiposity increases 24-h central blood pressure and arterial stiffness in young adults. This study examined 24-h central blood pressure and indirect measures of arterial stiffness (e.g., central pulse pressure) in physically inactive young adults with and without excess adiposity. METHODS: Body fat and ambulatory 24-h blood pressure were measured in 31 young adults (men: 22±4 years, N.=15; women: 22±5 years, N=16). Multi-frequency bioelectrical impedance measured body fat. Normal adiposity was defined as <20% body fat in men and <32% body fat in women, whereas excess adiposity was defined as ≥20% and ≥32% in men and women, respectively. Ambulatory 24-h central blood pressure was calculated based on brachial blood pressure and volumetric displacement waveforms. RESULTS: By design, the normal adiposity group had a lower body fat percentage (men: 15.5±4.6%; women: 20.8±2.5%) compared to the physically inactive excess adiposity group (men: 29.8±5.4%; women: 34.3±7.5%). Men and women with excess adiposity group had elevated central blood pressure (central systolic, P<0.05 vs. normal adiposity groups). Central pulse pressure was elevated in the excess adiposity group (men: 45±5 mmHg; women: 41±9 mmHg) compared to normal adiposity groups (men: 36±4 mmHg; women: 32±3 mmHg, P<0.05 for both), while other arterial stiffness (augmentation index and ambulatory arterial stiffness index) measures trended toward significance only in men with excess adiposity. CONCLUSIONS: Physically inactive men and women with excess adiposity have increased 24h central blood pressure and pulse pressure compared to physically inactive young adults with normal adiposity.

The temperature dependence of microbial community respiration is amplified by changes in species interactions.

Respiratory release of CO2 by microorganisms is one of the main components of the global carbon cycle. However, there are large uncertainties regarding the effects of climate warming on the respiration of microbial communities, owing to a lack of mechanistic, empirically tested theory that incorporates dynamic species interactions. We present a general mathematical model which predicts that thermal sensitivity of microbial community respiration increases as species interactions change from competition to facilitation (for example, commensalism, cooperation and mutualism). This is because facilitation disproportionately increases positive feedback between the thermal sensitivities of species-level metabolic and biomass accumulation rates at warmer temperatures. We experimentally validate our theoretical predictions in a community of eight bacterial taxa and show that a shift from competition to facilitation, after a month of co-adaptation, caused a 60% increase in the thermal sensitivity of respiration relative to de novo assembled communities that had not co-adapted. We propose that rapid changes in species interactions can substantially change the temperature dependence of microbial community respiration, which should be accounted for in future climate-carbon cycle models.

Outcomes Analysis of Textured Versus Smooth Tissue Expanders in Breast Reconstruction.

INTRODUCTION: Because of concerns related to the correlation of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) and textured implants, the use of smooth devices in breast reconstruction has been increasing. Currently, there is a paucity of literature evaluating the safety of smooth tissue expanders (STEs), which are now being used more frequently in first-stage breast reconstruction. This study sought to compare the safety and outcomes associated with STEs compared with textured tissue expanders in prosthesis-based breast reconstruction. METHODS: A single-institution retrospective review of 394 patients undergoing tissue expander-based breast reconstruction (147 smooth and 247 textured) between 2015 and 2019 was conducted. Patient demographics, comorbidities, treatment characteristics, complications, and surgical outcomes were evaluated. Data analysis was performed using Fisher exact and t tests. RESULTS: No significant difference in demographics or complication rates were identified, including rates of hematoma, seroma, wound dehiscence, delayed wound healing, infection, tissue expander malposition, nipple necrosis, mastectomy flap necrosis, reoperation, readmission, and explantation. Average follow-up was 19 and 22 months for the smooth and textured groups, respectively. No cases of BIA-ALCL were identified in either group. CONCLUSIONS: With equivocal safety profiles and no demonstrated risk in BIA-ALCL associated with STEs, this study supports the safety of using STEs compared with textured tissue expanders in prosthesis-based breast reconstruction with the advantage in preventing BIA-ALCL and concludes that there is no role for textured breast expanders.

Safety and efficacy of continuous subcutaneous foslevodopa-foscarbidopa in patients with advanced Parkinson's disease: a randomised, double-blind, active-controlled, phase 3 trial.

BACKGROUND: Levodopa is the most effective symptomatic therapy for Parkinson's disease, but patients with advanced Parkinson's disease develop motor fluctuations with chronic oral levodopa therapy. Foslevodopa-foscarbidopa is a soluble formulation of levodopa and carbidopa prodrugs that is delivered as a 24-h/day continuous subcutaneous infusion, and we aimed to assess the safety and efficacy of this formulation in patients with advanced Parkinson's disease. METHODS: A 12-week randomised, double-blind, double-dummy, active-controlled study was done at 65 academic and community study centres in the USA and Australia. Patients with levodopa-responsive advanced Parkinson's disease inadequately controlled on current therapy, including at least 2·5 h of average daily off time, were randomly assigned (1:1) to continuous subcutaneous infusion of foslevodopa-foscarbidopa plus oral placebo or to oral immediate-release levodopa-carbidopa plus continuous subcutaneous infusion of placebo solution. Randomisation was stratified by site by means of a permutated-block schedule with a block size of two. The participants, treating investigators, study site personnel, and sponsor were masked to treatment group allocation. The primary and first key secondary endpoint in the hierarchical testing strategy were change from baseline to week 12 in on time without troublesome dyskinesia and off time, respectively; both endpoints were evaluated by an intention-to-treat analysis applying a mixed model for repeated measures analysis. Safety and tolerability were assessed throughout the study. The study is completed and is listed on ClinicalTrials.gov, NCT04380142. FINDINGS: Between Oct 19, 2020, and Sept 29, 2021, of 270 participants screened and 174 enrolled, 141 were randomly assigned and received continuous subcutaneous infusion of foslevodopa-foscarbidopa plus oral placebo capsules (n=74) or oral encapsulated immediate-release levodopa-carbidopa plus continuous subcutaneous infusion of placebo solution (n=67). Compared with levodopa-carbidopa, foslevodopa-foscarbidopa showed a significantly greater increase in on time without troublesome dyskinesia (model-based mean [SE] 2·72 [0·52] vs 0·97 [0·50] h; difference 1·75 h, 95% CI 0·46 to 3·05; p=0·0083) and a significantly greater reduction in off time (-2·75 [0·50] vs -0·96 [0·49] h; difference -1·79 h, -3·03 to -0·54; p=0·0054). Hierarchical testing ended after the first secondary endpoint. Adverse events were reported in 63 (85%) of 74 patients in the foslevodopa-foscarbidopa group versus 42 (63%) of 67 in the levodopa-carbidopa group, and incidences of serious adverse events were similar between the groups (six [8%] of 74 vs four [6%] of 67, respectively). The most frequent adverse events in the foslevodopa-foscarbidopa group were infusion site adverse events (erythema 20 [27%]), pain 19 [26%]), cellulitis (14 [19%]), and oedema (nine [12%]), most of which were non-serious and mild-moderate in severity. The only system organ class that had more than one serious adverse event in the foslevodopa-foscarbidopa group was infections and infestations (catheter site cellulitis [one [1%]] and infusion site cellulitis [one [1%]). Adverse events led to premature discontinuation of study drug in 16 (22%) of 74 participants in the foslevodopa-foscarbidopa group versus one (1%) of 67 participants in the oral levodopa-carbidopa group. INTERPRETATION: Foslevodopa-foscarbidopa improved motor fluctuations, with benefits in both on time without troublesome dyskinesia and off time. Foslevodopa-foscarbidopa has a favourable benefit-risk profile and represents a potential non-surgical alternative for patients with advanced Parkinson's disease. FUNDING: AbbVie.

Energy requirements and carbon emissions for a low-carbon energy transition.

Achieving the Paris Agreement will require massive deployment of low-carbon energy. However, constructing, operating, and maintaining a low-carbon energy system will itself require energy, with much of it derived from fossil fuels. This raises the concern that the transition may consume much of the energy available to society, and be a source of considerable emissions. Here we calculate the energy requirements and emissions associated with the global energy system in fourteen mitigation pathways compatible with 1.5 °C of warming. We find that the initial push for a transition is likely to cause a 10-34% decline in net energy available to society. Moreover, we find that the carbon emissions associated with the transition to a low-carbon energy system are substantial, ranging from 70 to 395 GtCO2 (with a cross-scenario average of 195 GtCO2). The share of carbon emissions for the energy system will increase from 10% today to 27% in 2050, and in some cases may take up all remaining emissions available to society under 1.5 °C pathways.

National responsibility for ecological breakdown: a fair-shares assessment of resource use, 1970-2017.

BACKGROUND: Human impacts on earth-system processes are overshooting several planetary boundaries, driving a crisis of ecological breakdown. This crisis is being caused in large part by global resource extraction, which has increased dramatically over the past half century. We propose a novel method for quantifying national responsibility for ecological breakdown by assessing nations' cumulative material use in excess of equitable and sustainable boundaries. METHODS: For this analysis, we derived national fair shares of a sustainable resource corridor. These fair shares were then subtracted from countries' actual resource use to determine the extent to which each country has overshot its fair share over the period 1970-2017. Through this approach, each country's share of responsibility for global excess resource use was calculated. FINDINGS: High-income nations are responsible for 74% of global excess material use, driven primarily by the USA (27%) and the EU-28 high-income countries (25%). China is responsible for 15% of global excess material use, and the rest of the Global South (ie, the low-income and middle-income countries of Latin America and the Caribbean, Africa, the Middle East, and Asia) is responsible for only 8%. Overshoot in higher-income nations is driven disproportionately by the use of abiotic materials, whereas in lower-income nations it is driven disproportionately by the use of biomass. INTERPRETATION: These results show that high-income nations are the primary drivers of global ecological breakdown and they need to urgently reduce their resource use to fair and sustainable levels. Achieving sufficient reductions will likely require high-income nations to adopt transformative post-growth and degrowth approaches. FUNDING: None.

Economics for people and planet-moving beyond the neoclassical paradigm.

Despite substantial attention within the fields of public and planetary health on developing an economic system that benefits both people's health and the environment, heterodox economic schools of thought have received little attention within these fields. Ecological economics is a school of thought with particular relevance to public and planetary health. In this article, we discuss implications of key ecological economics ideas for public and planetary health, especially those related to critiques of gross domestic product as a measure of progress and economic growth as the dominant goal for economic and policy decision making. We suggest that ecological economics aligns well with public health goals, including concern for equality and redistribution. Ecological economics offers an opportunity to make the transition to an economic system that is designed to promote human and planetary health from the outset, rather than one where social and environmental externalities must be constantly corrected after the fact. Important ideas from ecological economics include the use of a multidimensional framework to evaluate economic and social performance, the prioritisation of wellbeing and environmental goals in decision making, policy design and evaluation that take complex relationships into account, and the role of provisioning systems (the physical and social systems that link resource use and social outcomes). We discuss possible interventions at the national scale that could promote public health and that align with the prioritisation of social and ecological objectives, including universal basic income or services and sovereign money creation. Overall, we lay the foundations for additional integration of ecological economics principles and pluralist economic thinking into public and planetary health scholarship and practice.

Potent and Selective Inhibitors of the Epidermal Growth Factor Receptor to Overcome C797S-Mediated Resistance.

The epidermal growth factor receptor (EGFR) harboring activating mutations is a clinically validated target in non-small-cell lung cancer, and a number of inhibitors of the EGFR tyrosine kinase domain, including osimertinib, have been approved for clinical use. Resistance to these therapies has emerged due to a variety of molecular events including the C797S mutation which renders third-generation C797-targeting covalent EGFR inhibitors considerably less potent against the target due to the loss of the key covalent-bond-forming residue. We describe the medicinal chemistry optimization of a biochemically potent but modestly cell-active, reversible EGFR inhibitor starting point with sub-optimal physicochemical properties. These studies culminated in the identification of compound 12 that showed improved cell potency, oral exposure, and in vivo activity in clinically relevant EGFR-mutant-driven disease models, including an Exon19 deletion/T790M/C797S triple-mutant mouse xenograft model.

A novel automated SARS-CoV-2 saliva PCR test protects a global asymptomatic workforce.

Regular PCR testing of nasopharyngeal swabs from symptomatic individuals for SARS-CoV-2 virus has become the established method by which health services are managing the COVID-19 pandemic. Businesses such as AstraZeneca have also prioritised voluntary asymptomatic testing to keep workplaces safe and maintain supply of essential medicines to patients. We describe the development of an internal automated SARS-CoV-2 testing programme including the transformative introduction of saliva as an alternative sample type.

Impact of Interindividual Differences in Plasma Fraction Unbound on the Pharmacokinetics of a Novel Syk Kinase Inhibitor in Beagle Dogs.

Inconsistencies in pharmacokinetic parameters between individual animals in preclinical studies are a common occurrence. Often such differences between animals are simply accepted as experimental variability rather than as indications of specific differences in animal phenotype that could lead to a different interpretation of the data. The fraction unbound in plasma is one factor influencing pharmacokinetic parameters and is typically determined using pooled plasma from multiple animals, making the assumption that there is limited population variance. However, this assumption is not often tested and may not hold true if there are polymorphisms affecting binding or variation in the concentrations of individual plasma proteins that could give rise to different fraction unbound phenotypes in individual animals. During profiling of a novel Syk inhibitor, AZ8399, striking interindividual differences in total plasma clearance and volume of distribution were observed between dogs consistent with differences in fraction unbound between animals. Determination of the fraction unbound showed a ∼5-fold difference in fraction unbound between the animals in the study. Broader analysis of individual dogs across a colony demonstrated a correlation between individual animal fraction unbound with total plasma clearance and volume of distribution. The concentrations of the common drug-binding proteins albumin and α1-acid glycoprotein in plasma were determined, and α1-acid glycoprotein levels were found to correlate with fraction unbound. Finally, single-nucleotide polymorphisms were identified at c.502 and c.522 of exon 5 of the dog α1-acid glycoprotein gene that may be correlated to the α1-acid glycoprotein concentration phenotype observed. SIGNIFICANCE STATEMENT: The current work demonstrates the potential for significant interindividual differences in plasma fraction unbound in beagle dogs and goes on to examine the underlying cause for the compound described. The findings suggest that the application of a population mean value of fraction unbound generated from a pooled sample may not always be appropriate and could introduce significant errors in scaling of in vitro clearance values, PBPK understanding, and interpretation of PKPD or toxicokinetic data in the context of unbound concentrations.

Clinical impact of subclonal EGFR T790M mutations in advanced-stage EGFR-mutant non-small-cell lung cancers.

Advanced non-small-cell lung cancer (NSCLC) patients with EGFR T790M-positive tumours benefit from osimertinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). Here we show that the size of the EGFR T790M-positive clone impacts response to osimertinib. T790M subclonality, as assessed by a retrospective NGS analysis of 289 baseline plasma ctDNA samples from T790M-positive advanced NSCLC patients from the AURA3 phase III trial, is associated with shorter progression-free survival (PFS), both in the osimertinib and the chemotherapy-treated patients. Both baseline and longitudinal ctDNA profiling indicate that the T790M subclonal tumours are enriched for PIK3CA alterations, which we demonstrate to confer resistance to osimertinib in vitro that can be partially reversed by PI3K pathway inhibitors. Overall, our results elucidate the impact of tumour heterogeneity on response to osimertinib in advanced stage NSCLC patients and could help define appropriate combination therapies in these patients.