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KRAS GTPases are activated in one-third of cancers, and KRAS(G12C) is one of the most common activating alterations in lung adenocarcinoma 1 , 2 . KRAS(G12C) inhibitors 3 , 4 are in phase-I clinical trials and early data show partial responses in nearly half of patients with lung cancer. How cancer cells bypass inhibition to prevent maximal response to therapy is not understood. Because KRAS(G12C) cycles between an active and inactive conformation 4 – 6 , and the inhibitors bind only to the latter, we tested whether isogenic cell populations respond in a non-uniform manner by studying the effect of treatment at a single-cell resolution. Here we report that, shortly after treatment, some cancer cells are sequestered in a quiescent state with low KRAS activity, whereas others bypass this effect to resume proliferation. This rapid divergent response occurs because some quiescent cells produce new KRAS(G12C) in response to suppressed mitogen-activated protein kinase output. New KRAS(G12C) is maintained in its active, drug-insensitive state by epidermal growth factor receptor and aurora kinase signalling. Cells without these adaptive changes—or cells in which these changes are pharmacologically inhibited—remain sensitive to drug treatment, because new KRAS(G12C) is either not available or exists in its inactive, drug-sensitive state. The direct targeting of KRAS oncoproteins has been a longstanding objective in precision oncology. Our study uncovers a flexible non-uniform fitness mechanism that enables groups of cells within a population to rapidly bypass the effect of treatment. This adaptive process must be overcome if we are to achieve complete and durable responses in the clinic. Populations of KRAS(G12C)-mutant cancer cells can rapidly bypass the effects of treatment with KRAS(G12C) inhibitors because a subset of cells escapes drug-induced quiescence by producing new KRAS(G12C) that is maintained in its active, drug-insensitive state.

KRAS GTPases are activated in one-third of cancers and KRASG12C is the most common activating alteration in lung adenocarcinoma1,2. KRASG12C inhibitors3,4 are in Phase-I clinical trials and early data show partial responses in 50% of lung cancer patients. How cancer cells bypass inhibition, to prevent maximal response to therapy, is not understood. Because KRASG12C cycles between an active and inactive conformation4-6, and the inhibitors only bind to the latter, we tested if isogenic cell populations respond non-uniformly by studying the effect of treatment at single-cell resolution. Here we report that shortly after treatment, some cancer cells are sequestered in a quiescent state with low KRAS activity, while others bypass this effect to resume proliferation. This rapid divergent response occurs because some quiescent cells produce new KRASG12C in response to suppressed mitogen-activated protein kinase output. New KRASG12C is maintained in its active/drug-insensitive state by epidermal growth-factor receptor and aurora kinase signaling. Cells without these adaptive changes (or cells where they are pharmacologically inhibited) remain sensitive to drug treatment, because new KRASG12C is either not available, or it exists in its inactive/drug-sensitive state. Directly targeting KRASoncoproteins has been a longstanding objective in precision oncology. Our study uncovers a flexible non-uniform fitness mechanism that enables groups of cells within a population to rapidly bypass the effect of treatment. This adaptive process must be overcome if we are to achieve complete and durable responses in the clinic.

Sodium fluoroacetate (FA) is a metabolic poison that systemically inhibits the tricarboxylic acid (TCA) cycle, causing energy deficiency and ultimately multi-organ failure. It poses a significant threat to society because of its high toxicity, potential use as a chemical weapon and lack of effective antidotal therapy. In this study, we investigated cell-permeable succinate prodrugs as potential treatment for acute FA intoxication. We hypothesized that succinate prodrugs would bypass FA-induced mitochondrial dysfunction, provide metabolic support, and prevent metabolic crisis during acute FA intoxication. To test this hypothesis, rats were exposed to FA (0.75 mg/kg) and treated with the succinate prodrug candidate NV354. Treatment efficacy was evaluated based on cardiac and cerebral mitochondrial respiration, mitochondrial content, metabolic profiles and tissue pathology. In the heart, FA increased concentrations of the TCA metabolite citrate (+ 4.2-fold, p  < 0.01) and lowered ATP levels (− 1.9-fold, p  < 0.001), confirming the inhibition of the TCA cycle by FA. High-resolution respirometry of cardiac mitochondria further revealed an impairment of mitochondrial complex V (CV)-linked metabolism, as evident by a reduced phosphorylation system control ratio (− 41%, p  < 0.05). The inhibition of CV-linked metabolism is a novel mechanism of FA cardiac toxicity, which has implications for drug development and which NV354 was unable to counteract at the given dose. In the brain, FA induced the accumulation of β-hydroxybutyrate (+ 1.4-fold, p  < 0.05) and the reduction of mitochondrial complex I (CI)-linked oxidative phosphorylation (OXPHOS CI ) (− 20%, p  < 0.01), the latter of which was successfully alleviated by NV354. This promising effect of NV354 warrants further investigations to determine its potential neuroprotective effects.

Importance Prior authorization (PA) requirements for buprenorphine are associated with lower provision of the medication for the treatment of opioid use disorder (OUD). While Medicare plans have eliminated PA requirements for buprenorphine, many Medicaid plans continue to require them. Objective To describe and classify buprenorphine coverage requirements based on thematic analysis of state Medicaid PA forms. Design, Setting, and Participants This qualitative study used a thematic analysis of 50 states’ Medicaid PA forms for buprenorphine between November 2020 and March 2021. Forms were obtained from the jurisdiction’s Medicaid websites and assessed for features suggesting barriers to buprenorphine access. A coding tool was developed based on a review of a sample of forms, including fields for behavioral health treatment recommendations or mandates, drug screening requirements, and dosage limitations. Main Outcomes and Measures Outcomes included PA requirements for different buprenorphine formulations. Additionally, PA forms were evaluated for various criteria such as behavioral health, drug screenings, dose-related recommendations or mandates or patient education. Results Among the total of 50 US states in the analysis, most states’ Medicaid plans required PA for at least 1 formulation of buprenorphine. However, the majority did not require a PA for buprenorphine-naloxone. Four key themes of coverage requirements were identified: restrictive surveillance (eg, requirements for urine drug screenings, random drug screenings, pill counts), behavioral health treatment recommendations or mandates (eg, mandatory counseling or 12-step meeting attendance), interfering with or restricting medical decision-making (eg, maximum daily dosages of 16 mg, requiring additional steps for dosages higher than 16 mg), and patient education (eg, information about adverse effects and interactions with other medications). Eleven states (22%) required urine drug screenings, 6 states (12%) required random urine drug screenings, and 4 states (8%) required pill counts. Fourteen states’ forms (28%) recommended therapy, and 7 (14%) required therapy, counseling, or participation in group sessions. Eighteen states (36%) specified dosage maximums; among them, 11 (22%) required additional steps for a daily dosage higher than 16 mg. Conclusion In this qualitative study of state Medicaid PA requirements for buprenorphine, themes were identified that included patient surveillance with drug screenings and pill counts, behavioral health treatment recommendations or mandates, patient education, and dosing guidance. These results suggest that state Medicaid plans’ buprenorphine PA requirements for OUD are in conflict with existing evidence and may negatively affect states’ efforts to address the opioid overdose crisis.

Although racial disparities in acute pain control are well established, the role of patient analgesic preference and the factors associated with these disparities remain unclear. To characterize racial disparities in opioid prescribing for acute pain after accounting for patient preference and to test the hypothesis that racial disparities may be mitigated by giving clinicians additional information about their patients' treatment preferences and risk of opioid misuse. This study is a secondary analysis of data collected from Life STORRIED (Life Stories for Opioid Risk Reduction in the ED), a multicenter randomized clinical trial conducted between June 2017 and August 2019 in the emergency departments (EDs) of 4 academic medical centers. Participants included 1302 patients aged 18 to 70 years who presented to the ED with ureter colic or musculoskeletal back and/or neck pain. The treatment arm was randomized to receive a patient-facing intervention (not examined in this secondary analysis) and a clinician-facing intervention that consisted of a form containing information about each patient's analgesic treatment preference and risk of opioid misuse. Concordance between patient preference for opioid-containing treatment (assessed before ED discharge) and receipt of an opioid prescription at ED discharge. Among 1302 participants in the Life STORRIED clinical trial, 1012 patients had complete demographic and treatment preference data available and were included in this secondary analysis. Of those, 563 patients (55.6%) self-identified as female, with a mean (SD) age of 40.8 (14.1) years. A total of 455 patients (45.0%) identified as White, 384 patients (37.9%) identified as Black, and 173 patients (17.1%) identified as other races. After controlling for demographic characteristics and clinical features, Black patients had lower odds than White patients of receiving a prescription for opioid medication at ED discharge (odds ratio [OR], 0.42; 95% CI, 0.27-0.65). When patients who did and did not prefer opioids were considered separately, Black patients continued to have lower odds of being discharged with a prescription for opioids compared with White patients (among those who preferred opioids: OR, 0.43 [95% CI, 0.24-0.77]; among those who did not prefer opioids: OR, 0.45 [95% CI, 0.23-0.89]). These disparities were not eliminated in the treatment arm, in which clinicians were given additional data about their patients' treatment preferences and risk of opioid misuse. In this secondary analysis of data from a randomized clinical trial, Black patients received different acute pain management than White patients after patient preference was accounted for. These disparities remained after clinicians were given additional patient-level data, suggesting that a lack of patient information may not be associated with opioid prescribing disparities. ClinicalTrials.gov Identifier: NCT03134092.