A common polymorphism in the Intelectin-1 gene influences mucus plugging in severe asthma.

By incompletely understood mechanisms, type 2 (T2) inflammation present in the airways of severe asthmatics drives the formation of pathologic mucus which leads to airway mucus plugging. Here we investigate the molecular role and clinical significance of intelectin-1 (ITLN-1) in the development of pathologic airway mucus in asthma. Through analyses of human airway epithelial cells we find that ITLN1 gene expression is highly induced by interleukin-13 (IL-13) in a subset of metaplastic MUC5AC+ mucus secretory cells, and that ITLN-1 protein is a secreted component of IL-13-induced mucus. Additionally, we find ITLN-1 protein binds the C-terminus of the MUC5AC mucin and that its deletion in airway epithelial cells partially reverses IL-13-induced mucostasis. Through analysis of nasal airway epithelial brushings, we find that ITLN1 is highly expressed in T2-high asthmatics, when compared to T2-low children. Furthermore, we demonstrate that both ITLN-1 gene expression and protein levels are significantly reduced by a common genetic variant that is associated with protection from the formation of mucus plugs in T2-high asthma. This work identifies an important biomarker and targetable pathways for the treatment of mucus obstruction in asthma.

Rechallenges without desensitization following platinum-based chemotherapy reactions.

BACKGROUND: There is increasing interest in non-desensitization protocols as a potential way to reintroduce chemotherapy following hypersensitivity reactions (HSR). OBJECTIVE: To provide insight into the potential utility of non-desensitization reintroduction, particularly at institutions where allergy consultation may not be available. METHODS: For 70 patients with platinum HSR who underwent rechallenge with standard (≤2 hours), extended (1-bag, 1-step, 4-6 hours), or titrated (4-to-5-bag and -step, 6-7.5 hours) infusions between 1/2014 and 7/2019, demographics and clinical characteristics were reviewed and initial and breakthrough reactions (BTR) were graded using Common Terminology Criteria for Adverse Events version 5.0 (CTCAE v5.0). Tolerance (no BTR) and completion (dose completed despite BTR) were compared using Fisher's exact test. RESULTS: Patients (mean [standard deviation] age 57 [13] years, initial HSR grade 2 [1]), were rechallenged with standard (n = 8), extended (n = 23), or titrated (n = 22) infusions after oxaliplatin HSR; and standard (n = 5) or titrated (n = 12) after carboplatin HSR. Tolerance and completion were higher for extended versus (vs) standard (tolerance-87%-vs-8%, p < 0.005; completion-96%-vs-38%, p < 0.005) and titrated versus standard (tolerance-76%-vs-8%, p < 0.005; completion-79%-vs-38%, p < 0.05) infusions. CONCLUSIONS: Extended and titrated infusions may increase reintroduction safety compared to standard infusions. Further investigation into extended infusions may provide a safe alternative to standard infusions in patients who may not have access to desensitization at their institution.

Changes in systemic cancer therapy in Australia during the Delta and Omicron waves of the COVID-19 pandemic (2021-2022): a controlled interrupted time series analysis.

OBJECTIVES: Australian lockdowns in response to the initial coronavirus disease 2019 (COVID-19) outbreak in 2020 were associated with small and transient changes in the use of systemic cancer therapy. We aimed to investigate the impacts of the longer and more restrictive lockdowns in the Australian states of New South Wales (NSW) and Victoria during both the Delta subvariant lockdowns in mid-2021 and the Omicron subvariant outbreak in late 2021/early 2022. STUDY TYPE: Population-based, controlled interrupted time series analysis. METHODS: We conducted a national observational study using de-identified records of government-subsidised cancer medicines dispensed to a random 10% sample of Australians between July 2018 and July 2022. We used controlled interrupted time series analysis to investigate changes in the dispensing, initiation and discontinuation of all cancer medicines dispensed to residents of NSW and Victoria, using the rest of Australia as a control series. We used quasi-Poisson regression to model weekly counts and estimate incidence rate ratios (IRRs) for the effect of (each) the Delta phase lockdown and the Omicron outbreak on our systemic cancer therapy outcomes. RESULTS: Between July 2018 and July 2022, cancer medicines were dispensed 592 141 times to 33 198 people in NSW and Victoria. Overall, there were no changes to the rates of dispensing, initiation or discontinuation of antineoplastics during the Delta phase lockdowns. In both states during the Omicron outbreak, there were significant decreases in the dispensing of antineoplastics (NSW IRR 0.89; 95% confidence interval [CI] 0.84, 0.93. Victoria IRR 0.92; 95% CI 0.88, 0.96) and in the initiation of endocrine therapy (NSW IRR 0.85; 95% CI 0.74, 0.99. Victoria IRR 0.78; 95% CI 0.65, 0.94), and no changes in the discontinuation of any systemic cancer therapy. CONCLUSIONS: The 2021 lockdowns and 2021/2022 Omicron outbreaks in NSW and Victoria had significant impacts on the dispensing, initiation and discontinuation of systemic cancer therapies, however, the overall effects were minimal. The impacts of lockdowns were less significant than the Omicron outbreaks, suggesting COVID-19 infection, health system capacity, and patient and community concerns were important factors for treatment changes.

Prescribing practices of inhaled corticosteroids for premature infants in the neonatal intensive care unit.

OBJECTIVE: Despite limited safety and efficacy data, inhaled corticosteroids (ICS) are prescribed to premature infants in the neonatal intensive care unit (NICU). We examined contemporary use and risk factors for ICS use in the NICU. STUDY DESIGN: Infants <33 weeks gestational age and <1500 gm birth weight discharged from Pediatrix Medical Group NICUs between 2010 and 2020 were included. We evaluated the association between ICS prescription and clinical characteristics using univariable and multivariable logistic regression. RESULTS: Of 74,123 infants from 308 NICUs, 9253 (12.5%) were prescribed ICS: budesonide, fluticasone, or beclomethasone. Diagnosis of bronchopulmonary dysplasia (BPD), earlier gestational age, male sex, longer mechanical ventilation, oxygen support, and systemic steroids were independent risk factors for ICS prescription. CONCLUSIONS: Use of ICS is common in many NICUs and is associated with a diagnosis of BPD and healthcare utilization. Prospective trials are needed to establish the safety, efficacy, and optimal indication in this vulnerable population.

Persistent mucus plugs in proximal airways are consequential for airflow limitation in asthma.

BACKGROUNDInformation about the size, airway location, and longitudinal behavior of mucus plugs in asthma is needed to understand their role in mechanisms of airflow obstruction and to rationally design muco-active treatments.METHODSCT lung scans from 57 patients with asthma were analyzed to quantify mucus plug size and airway location, and paired CT scans obtained 3 years apart were analyzed to determine plug behavior over time. Radiologist annotations of mucus plugs were incorporated in an image-processing pipeline to generate size and location information that was related to measures of airflow.RESULTSThe length distribution of 778 annotated mucus plugs was multimodal, and a 12 mm length defined short ("stubby", ≤12 mm) and long ("stringy", >12 mm) plug phenotypes. High mucus plug burden was disproportionately attributable to stringy mucus plugs. Mucus plugs localized predominantly to airway generations 6-9, and 47% of plugs in baseline scans persisted in the same airway for 3 years and fluctuated in length and volume. Mucus plugs in larger proximal generations had greater effects on spirometry measures than plugs in smaller distal generations, and a model of airflow that estimates the increased airway resistance attributable to plugs predicted a greater effect for proximal generations and more numerous mucus plugs.CONCLUSIONPersistent mucus plugs in proximal airway generations occur in asthma and demonstrate a stochastic process of formation and resolution over time. Proximal airway mucus plugs are consequential for airflow and are in locations amenable to treatment by inhaled muco-active drugs or bronchoscopy.TRIAL REGISTRATIONClinicaltrials.gov; NCT01718197, NCT01606826, NCT01750411, NCT01761058, NCT01761630, NCT01716494, and NCT01760915.FUNDINGAstraZeneca, Boehringer-Ingelheim, Genentech, GlaxoSmithKline, Sanofi-Genzyme-Regeneron, and TEVA provided financial support for study activities at the Coordinating and Clinical Centers beyond the third year of patient follow-up. These companies had no role in study design or data analysis, and the only restriction on the funds was that they be used to support the SARP initiative.

Prevalence of Australians exposed to potentially cardiotoxic cancer medicines: a population-based cohort study.

Background: Cardiovascular disease (CVD) and cancer are leading causes of death and people with cancer are at higher risk of developing CVD than the general population. Many cancer medicines have cardiotoxic effects but the size of the population exposed to these potentially cardiotoxic medicines is not known. We aimed to determine the prevalence of exposure to potentially cardiotoxic cancer medicines in Australia. Methods: We identified potentially cardiotoxic systemic cancer medicines through searching the literature and registered product information documents. We conducted a retrospective cohort study of Australians dispensed potentially cardiotoxic cancer medicines between 2005 and 2021, calculating age-standardised annual prevalence rates of people alive with exposure to a potentially cardiotoxic medicine during or prior to each year of the study period. Findings: We identified 108,175 people dispensed at least one potentially cardiotoxic cancer medicine; median age, 64 (IQR: 52-74); 57% female. Overall prevalence increased from 49 (95%CI: 48.7-49.3)/10,000 to 232 (95%CI: 231.4-232.6)/10,000 over the study period; 61 (95%CI: 60.5-61.5)/10,000 to 293 (95%CI: 292.1-293.9)/10,000 for females; and 39 (95%CI: 38.6-39.4)/10,000 to 169 (95%CI: 168.3-169.7)/10,000 for males. People alive five years following first exposure increased from 29 (95%CI: 28.8-29.2)/10,000 to 134 (95%CI: 133.6-134.4)/10,000; and from 22 (95%CI: 21.8-22.2)/10,000 to 76 (95%CI: 75.7-76.3)/10,000 for those alive at least 10 years following first exposure. Most people were exposed to only one potentially cardiotoxic medicine, rates of which increased from 39 (95%CI: 38.7-39.3)/10,000 in 2005 to 131 (95%CI: 130.6-131.4)/10,000 in 2021. Interpretation: The number of people exposed to efficacious yet potentially cardiotoxic cancer medicines in Australia is growing. Our findings can support the development of service planning and create awareness about the magnitude of cancer treatment-related cardiotoxicities. Funding: NHMRC Centre for Research Excellence in Medicines Intelligence, Cancer Institute NSW Early Career Fellowship.

Harnessing Real-World Evidence to Advance Cancer Research.

Randomized controlled trials (RCTs) form a cornerstone of oncology research by generating evidence about the efficacy of therapies in selected patient populations. However, their implementation is often resource- and cost-intensive, and their generalisability to patients treated in routine practice may be limited. Real-world evidence leverages data collected about patients receiving clinical care in routine practice outside of clinical trial settings and provides opportunities to identify and address gaps in clinical trial evidence. This review outlines the strengths and limitations of real-world and RCT evidence and proposes a framework for the complementary use of the two bodies of evidence to advance cancer research. There are challenges to the implementation of real-world research in oncology, including heterogeneity of data sources, timely access to high-quality data, and concerns about the quality of methods leveraging real-world data, particularly causal inference. Improved understanding of the strengths and limitations of real-world data and ongoing efforts to optimise the conduct of real-world evidence research will improve its reliability, understanding and acceptance, and enable the full potential of real-world evidence to be realised in oncology practice.

Exploring antiviral and anti-inflammatory effects of thiol drugs in COVID-19.

The redox status of the cysteine-rich SARS-CoV-2 spike glycoprotein (SARS-2-S) is important for the binding of SARS-2-S to angiotensin-converting enzyme 2 (ACE2), suggesting that drugs with a functional thiol group ("thiol drugs") may cleave cystines to disrupt SARS-CoV-2 cell entry. In addition, neutrophil-induced oxidative stress is a mechanism of COVID-19 lung injury, and the antioxidant and anti-inflammatory properties of thiol drugs, especially cysteamine, may limit this injury. To first explore the antiviral effects of thiol drugs in COVID-19, we used an ACE-2 binding assay and cell entry assays utilizing reporter pseudoviruses and authentic SARS-CoV-2 viruses. We found that multiple thiol drugs inhibit SARS-2-S binding to ACE2 and virus infection. The most potent drugs were effective in the low millimolar range, and IC50 values followed the order of their cystine cleavage rates and lower thiol pKa values. To determine if thiol drugs have antiviral effects in vivo and to explore any anti-inflammatory effects of thiol drugs in COVID-19, we tested the effects of cysteamine delivered intraperitoneally to hamsters infected with SARS-CoV-2. Cysteamine did not decrease lung viral infection, but it significantly decreased lung neutrophilic inflammation and alveolar hemorrhage. We speculate that the concentration of cysteamine achieved in the lungs with intraperitoneal delivery was insufficient for antiviral effects but sufficient for anti-inflammatory effects. We conclude that thiol drugs decrease SARS-CoV-2 lung inflammation and injury, and we provide rationale for future studies to test if direct (aerosol) delivery of thiol drugs to the airways might also result in antiviral effects.

Generalizability of immune checkpoint inhibitor trials to real-world patients with advanced non-small cell lung cancer.

INTRODUCTION: Based on data from randomized controlled trials (RCTs), immune checkpoint inhibitors (ICI) are standard-of-care in advanced non-small cell lung cancer (aNSCLC). However, trial eligibility criteria are restrictive, and participants and outcomes may not represent the wider population. We aim to assess the generalizability of key phase III RCTs to real-world patients. METHODS: Among aNSCLC patients enrolled in the Embedding Research (and Evidence) in Cancer Healthcare (EnRICH) program between 26/6/17-18/2/21, we assessed the proportion of patients who fulfilled key trial eligibility criteria: performance status (PS) 0-1, normal laboratory results, no EGFR/ALK mutations, no exclusionary comorbidities (previous cancer, conditions necessitating steroid use, autoimmune diseases, HIV, hepatitis B/C, tuberculosis, interstitial lung disease, organ transplantation). We defined patients who met all assessed criteria as trial-typical and describe ICI uptake and overall survival (OS). RESULTS: Of 454 patients (median age 71 years, 42.1% female), 30% were trial-typical. Less than half received ICI (47.6%), with trial-typical patients more likely to receive ICI (69.1% vs 38.4%, adjusted odds ratio 3.77, 95% CI 2.40-5.91). Median OS was 10.2 and 5.4 months in patients receiving first- and second-line ICI, respectively. Rationalizing trial criteria to include patients with PS ≤ 2 and exclude those with targetable mutations, steroid use, autoimmune diseases, interstitial lung disease, tuberculosis or organ transplantation increased the proportion of trial-typical patients to 57.3%. CONCLUSIONS: Landmark phase III RCTs in aNSCLC have limited generalizability. OS of real-world patients receiving ICI is shorter than reported in trials. Novel ICI trials should consider broader eligibility criteria to improve their generalizability.

A phase 2 study of anastrozole in patients with oestrogen receptor and/progesterone receptor positive recurrent/metastatic granulosa cell tumours/sex-cord stromal tumours of the ovary: The PARAGON/ANZGOG 0903 trial.

BACKGROUND: Hormonal therapies are commonly prescribed to patients with metastatic granulosa cell tumours (GCT), based on high response rates in small retrospective studies. Aromatase inhibitors (AIs) are reported to have high response rates and an accepted treatment option. We report the results of a phase 2 trial of an AI in recurrent/metastatic GCTs. METHODS: 41 patients with recurrent ER/PR + ve GCT received anastrozole 1 mg daily until progression or unacceptable toxicity. The primary endpoint was clinical benefit rate (CBR) at 12 weeks, evaluated by RECIST1.1 criteria. Secondary endpoints included progression-free survival (PFS), CBR duration, quality of life and toxicity. RESULTS: The CBR at 12 weeks in 38 evaluable patients was 78.9%, which included one (2.6%; 95% CI: 0.5-13.5%) partial response and 76.3% stable disease. Two additional patients without measurable disease were stable, based on inhibin. Median PFS was 8.6 m (95% CI 5.5-13.5 m). There were delayed responses observed after 12 weeks with a total of 4 pts. (10.5%; 95% CI 4.2%-24.1%) with a RECIST partial response; 23 (59%) patients were progression-free at 6 months. The adverse effects were predominantly low grade. CONCLUSIONS: This is the first prospective trial of hormonal therapy in GCTs. Although there was a high CBR, the objective response rate to anastrozole was much lower than the pooled response rates of >70% to AIs reported in most retrospective series and case reports. PARAGON demonstrates the importance of prospective trials in rare cancers and the need to reconsider the role of AIs as single agents in GCTs.

Changes in systemic cancer therapy in Australia during the COVID-19 pandemic: a population-based study.

BACKGROUND: Since the emergence of COVID-19 there have been increasing global concerns about delays and/or discontinuations in cancer care. However, it is unclear to what extent systemic cancer therapy was impacted by COVID-19 in countries with relatively low COVID-19 infection rates. We examined changes in systemic cancer therapy in Australia during the COVID-19 pandemic. METHODS: We conducted a national observational study using de-identified records of government-subsidised cancer medicines dispensed to a random 10% sample of Australians between January 2017 to December 2020. We reported monthly dispensing and initiation rates of antineoplastic (chemo-, immuno- and targeted therapy), endocrine and supportive medicines per 100,000 population. We reported monthly discontinuation rates (defined as ≥90 days gap between cancer medicine dispensings) per 1,000 people treated. We used interrupted time series analysis to examine changes during times of increased COVID-19 risk and related public health measures (March, April and July 2020). FINDINGS: Between January 2017 and December 2020, 1,011,255 cancer medicines were dispensed to 51,515 people. Overall, there were no reductions in antineoplastic dispensing or initiation during the COVID-19 pandemic. In March 2020, we observed a temporary increase of 39/100,000 (95% CI: 14 to 65/100,000) in antineoplastic dispensing, driven by immunotherapy and targeted therapy. In April 2020, we observed a temporary decrease in chemotherapy initiation (-2/100,000, 95% CI: -4 to -1/100,000) and temporary increase in discontinuation of all antineoplastic medicines (35/1,000, 95% CI: 20 to 51/1,000), but these changes were not sustained. INTERPRETATION: The effective control of COVID-19 in Australia appears to have mitigated the initial impact of COVID-19 on systemic cancer therapy. We observed only small and temporary changes in the use of some cancer medicines early in the pandemic. FUNDING: National Health and Medical Research Council; National Breast Cancer Foundation; Translational Cancer Research Network, supported by the Cancer Institute NSW.

Are clinical trial eligibility criteria representative of older patients with lung cancer? A population-based data linkage study.

OBJECTIVES: Older adults constitute the majority of patients with lung cancer. However, they are under-represented in clinical trials as eligibility criteria often restrict enrolment based on comorbidities that are common with aging. We aimed to describe comorbidities relating to trial exclusion criteria in older adults with lung cancer, determine the proportion that would typically be excluded from trials, and examine the impact on treatment uptake. MATERIALS AND METHODS: We conducted a population-based study of people aged ≥65 years diagnosed with metastatic lung cancer using linked data for clients of the Australian Government Department of Veterans' Affairs (2005-2015). We defined trial-typical patients based on the absence of comorbidities related to the following: inadequate organ (cardiac, renal, hepatic, marrow) function; cognitive dysfunction; poor performance status (PS); prior malignancy within 5 years. We report systemic therapy uptake within 3 months of diagnosis. RESULTS: Our study included 677 patients (median age 84). Over half (53.4%) were not trial-typical, with the most common reasons being poor PS (37.5%), cardiac disease (19.2%), and prior cancer (12.9%). Eighty-two (12.1%) received systemic therapy. Patients with poor PS, cardiac disease, and dementia had lower treatment uptake rates. However, there was no significant difference in treatment uptake between trial-typical and non-trial-typical patients (13.4 vs 11.0%). CONCLUSION: More than half of older adults with advanced lung cancer would be typically excluded from trial participation. Future clinical trials of older adults need to consider broader eligibility criteria to better reflect this population to gain the best evidence for their care.

Trastuzumab emtansine for HER2-positive metastatic breast cancer: Outcomes from a whole-of-population Australian cohort.

PURPOSE: We aim to describe the treatment patterns and overall survival (OS) outcomes in patients receiving trastuzumab emtansine (T-DM1) for HER2-positive metastatic breast cancer (HER2+MBC) in routine clinical care. METHODS: Retrospective, whole-of-population cohort study of people initiating T-DM1 for HER2+MBC between October 2015 and May 2019 in Australia. We used dispensing claims to estimate time-to-T-DM1 initiation, duration of treatment, and treatments administered prior to and following T-DM1 therapy. We estimated OS from T-DM1 initiation and stratified results based on whether patients received first- or second-line T-DM1 treatment. We benchmarked outcomes to those reported in the pivotal, EMILIA trial. RESULTS: 345 patients initiated T-DM1: 309 as second-line therapy for HER2+MBC and 36 as first-line therapy. 51% of patients had received endocrine therapy and 98% of second-line patients received pertuzumab prior to starting T-DM1. The median age was 57 years (53 in EMILIA); median time-to-T-DM1 initiation from start of HER2-targeted therapy for HER2+MBC was 11.6 months (IQR: 7.9-16.6); median duration of T-DM1 treatment was 6.5 months (3.1-13.5; 7.6 months in EMILIA), and median OS was 19.3 months (7.9-29.5; 29.9 months in EMILIA). CONCLUSIONS: Our findings highlight differences in patient characteristics (older, more previous pertuzumab therapy) and outcomes (shorter OS) from the T-DM1 pivotal trial and provide real-world estimates that can inform patient, clinician and policy, decisions around the use of HER2-targeted therapies in routine clinical care.

Cardiac assessment in Australian patients receiving (neo)adjuvant trastuzumab for HER2-positive early breast cancer: a population-based study.

PURPOSE: Cardiac function assessment is important for detecting and managing trastuzumab-associated cardiotoxicity. Our study estimates rates and predictors of cardiac assessment among patients receiving trastuzumab for HER2-positive early breast cancer (HER2+EBC) in Australia. METHODS: We conducted a retrospective cohort study of Australians initiating (neo)adjuvant trastuzumab for HER2+EBC between 1 January 2015 and 15 April 2019. We used administrative claims to determine the number of patients receiving guideline-recommended assessment, i.e. evidence of baseline cardiac assessment (between 120 days before and 30 days after trastuzumab initiation) and regular on-treatment cardiac assessments (at least every 120 days). We examined factors associated with baseline and regular on-treatment cardiac assessment. RESULTS: Our study includes 5621 patients (median age 56 years), of whom 4984 (88.7%) had a baseline cardiac function test. Among 4280 patients with at least 12 months of follow-up, 2702 (63.1%) had guideline-recommended cardiac assessment. Rates of guideline-recommended assessment increased with later year of diagnosis (60.9% in 2015 vs 68.3% in 2018, OR 1.34, 95% CI 1.06-1.69). Patients with higher baseline comorbidities and greater socioeconomic disadvantage were less likely to have guideline-recommended cardiac assessment. Cardiac assessment practices varied by State/Territory. There was no association between baseline cardiac risk or anthracycline use and the likelihood of receiving guideline-recommended cardiac assessment. CONCLUSION: The majority of patients receiving (neo)adjuvant trastuzumab had guideline-recommended baseline and on-treatment cardiac assessment. Variations in cardiac assessment predominantly related to system-level factors, such as year of diagnosis and geography, rather than individual patient factors.

Thiol drugs decrease SARS-CoV-2 lung injury in vivo and disrupt SARS-CoV-2 spike complex binding to ACE2 in vitro.

Neutrophil-induced oxidative stress is a mechanism of lung injury in COVID-19, and drugs with a functional thiol group ("thiol drugs"), especially cysteamine, have anti-oxidant and anti-inflammatory properties that could limit this injury. Thiol drugs may also alter the redox status of the cysteine-rich SARS-CoV-2 spike glycoprotein (SARS-2-S) and thereby disrupt ACE2 binding. Using ACE2 binding assay, reporter virus pseudotyped with SARS-CoV-2 spikes (ancestral and variants) and authentic SARS-CoV-2 (Wuhan-1), we find that multiple thiol drugs inhibit SARS-2-S binding to ACE2 and virus entry into cells. Pseudoviruses carrying variant spikes were less efficiently inhibited as compared to pseudotypes bearing an ancestral spike, but the most potent drugs still inhibited the Delta variant in the low millimolar range. IC50 values followed the order of their cystine cleavage rates and lower thiol pKa values. In hamsters infected with SARS-CoV-2, intraperitoneal (IP) cysteamine decreased neutrophilic inflammation and alveolar hemorrhage in the lungs but did not decrease viral infection, most likely because IP delivery could not achieve millimolar concentrations in the airways. These data show that thiol drugs inhibit SARS-CoV-2 infection in vitro and reduce SARS-CoV-2-related lung injury in vivo and provide strong rationale for trials of systemically delivered thiol drugs as COVID-19 treatments. We propose that antiviral effects of thiol drugs in vivo will require delivery directly to the airways to ensure millimolar drug concentrations and that thiol drugs with lower thiol pKa values are most likely to be effective.