Improved Accuracy/Completeness of EHR Race/Ethnicity Data: A Requisite Step to Address Disparities in Care.

Accurate and complete racial/ethnic data in the electronic health record are a requisite step to addressing disparities in neurologic care, and at local, regional, and national levels. The current data pertaining to the patients' race and ethnicity contained in the electronic health record are inadequate. This article outlines recommendations at the individual practice and electronic health record vendor level to improve documentation of race and ethnicity.

'I just never wanted them to feel uncomfortable': Barriers to pharmacy-based identification and treatment of hepatitis C in Victoria, Canada.

Background: Canada is currently on target to reach the 2030 WHO goal of HCV elimination. Continued high rates of treatment are required to meet this goal. Novel models such as Tayside, Scotland pharmacy-based HCV screening and treatment have proven successful to engage people who use drugs (PWUD) in HCV therapy with a simplified, task-shifted cascade of care. This study seeks to determine whether these successes can be replicated at community pharmacies in Victoria BC. Methods: Four pharmacies who work with PWUD and provide opioid agonist therapy were trained to provide consent and perform point-of-care HCV antibody screening. They were supported by study nurse to link to HCV RNA testing when antibody positive patients were identified, with HCV treatment offered to RNA positive participants. Qualitative interviews were conducted with five pharmacy staff to explore experiences and feasibility of pharmacists in HCV care cascade. Results: Pharmacy staff completed 200 HCV OraQuick tests between October 2020 and June 2022: 65 HCV antibody positive, 29 HCV RNA negative (25 previously treated and 4 self-cleared). Of the 26 RNA positive participants, one is awaiting treatment, 25 people have started treatment, 22 achieving SVR. Although the onset of the COVID-19 pandemic was a fundamental barrier incorporating HCV testing at pharmacies, stigma related to HCV and illicit drug use continues to impact this process. Conclusions: This innovative pharmacy-based approach found people with limited connection to primary health care to test and treat HCV but requires more training and support to be more widely feasible.

Examining the National Representativeness of the Axon Registry: A Neurology-Specific Patient Registry.

BACKGROUND AND OBJECTIVES: The objective of this study was to determine the external validity of the Axon Registry by comparing the 2019 calendar year data with 2 nationally representative, publicly available data sources, specifically the National Ambulatory Medical Care Survey (NAMCS) and the Medical Expenditure Panel Survey (MEPS). The Axon Registry is the American Academy of Neurology's neurology-focused qualified clinical data registry that reports and analyzes electronic health record data from participating US neurology providers. Its key function is to support quality improvement within ambulatory neurology practices while also promoting high-quality evidence-based care in clinical neurology. We compared demographics of patients who had an outpatient or office visit with a neurologist along with prevalence of selected neurologic conditions and neurologic procedures across the 3 data sets. METHODS: We performed a cross-sectional, retrospective comparison of 3 data sets: NAMCS (2012-2016), MEPS (2013-2017, 2019), and Axon Registry (2019). We obtained patient demographics (age, birth sex, race, ethnicity), patient neurologic conditions (headache, epilepsy, cerebrovascular disease, multiple sclerosis, parkinsonism, dementia, spinal pain, and polyneuropathy), provider location, and neurologic procedures (neurology visits, MR/CT neuroimaging studies and EEG/EMG neurophysiologic studies). Parameter estimates from the pooled 5-year samples of the 2 public data sets, calculated at the visit level, were compared descriptively with those of the Axon Registry. We calculated Cohen h and performed Wald tests (α = 0.05) to conduct person-level statistical comparisons between MEPS 2019 and Axon Registry 2019 data. RESULTS: The Axon Registry recorded 1.3 M annual neurology visits (NAMCS, 11 M; MEPS, 22 M) and 645 K people with neurologic conditions (MEPS, 10 M). Compared with the pooled national surveys, the Axon Registry has similar patient demographics, neurologic condition prevalence, neuroimaging and neurophysiologic utilization, and provider location. In direct comparison with MEPS 2019, the Axon Registry 2019 had fewer children (2% vs 7%), more elderly persons (21% vs 16%), fewer non-Black and non-White race persons (5% vs 8%), less number of patients with epilepsy (10% vs 13%), more patients with dementia (8% vs 6%), more patients with cerebrovascular disease (11% vs 8%), and a greater predominance of neurology providers in the Midwest (25% vs 20%). The only difference with a non-negligible effect size was the proportion of people younger than 15 years (Cohen h = 0.25). DISCUSSION: The Axon Registry demonstrates high concordance with 2 nationally representative surveys. Recruiting more and diverse neurology providers will further improve the volume, representativeness, and value of the Axon Registry.

IL-38 blockade induces anti-tumor immunity by abrogating tumor-mediated suppression of early immune activation.

Immune checkpoint inhibitors that overcome T cell suppressive mechanisms in tumors have revolutionized the treatment of cancer but are only efficacious in a small subset of patients. Targeting suppressive mechanisms acting on innate immune cells could significantly improve the incidence of clinical response by facilitating a multi-lineage response against the tumor involving both adaptive and innate immune systems. Here, we show that intra-tumoral interleukin (IL)-38 expression is a feature of a large frequency of head and neck, lung and cervical squamous cancers and correlates with reduced immune cell numbers. We generated IMM20324, an antibody that binds human and mouse IL-38 proteins and inhibits the binding of IL-38 to its putative receptors, interleukin 1 receptor accessory protein-like 1 (IL1RAPL) and IL-36R. In vivo, IMM20324 demonstrated a good safety profile, delayed tumor growth in a subset of mice in an EMT6 syngeneic model of breast cancer, and significantly inhibited tumor expansion in a B16.F10 melanoma model. Notably, IMM20324 treatment resulted in the prevention of tumor growth following re-implantation of tumor cells, indicating the induction of immunological memory. Furthermore, exposure of IMM20324 correlated with decreased tumor volume and increased levels of intra-tumoral chemokines. Together, our data suggest that IL-38 is expressed in a high frequency of cancer patients and allows tumor cells to suppress anti-tumor immunity. Blockade of IL-38 activity using IMM20324 can re-activate immunostimulatory mechanisms in the tumor microenvironment leading to immune infiltration, the generation of tumor-specific memory and abrogation of tumor growth.

Measuring Ambulatory Racial and Ethnic Neurologic Disparities With the Axon Registry.

Background and Objectives: The primary objective is to examine potential racial and ethnic (R/E) disparities in ambulatory neurology quality measures within the American Academy of Neurology Axon Registry. R/E disparities in neurologic US morbidity and mortality have been clearly documented. Despite these findings, there have been no nationwide examinations of how ambulatory neurologic care affects these negative health outcomes. Methods: This was a retrospective nonrandomized cohort study of patients in the AAN Axon Registry. The Axon Registry is a neurology-specific outpatient quality registry that collects, reports, and analyzes real-world deidentified electronic health record (EHR) data. Patients were included in the study if they contributed toward one of the selected quality measures for multiple sclerosis, epilepsy, Parkinson disease, or headache during the study period of January 1, 2019-December 31, 2019. Descriptive analyses of patient demographics were performed and then stratified by race and ethnicity. Results: There were a total of 633,672 patients included in these analyses. Separate analyses were performed for race (64% White, 8% Black, 1% Asian, and 27% unknown) and ethnicity (52% not Hispanic, 5% Hispanic, and 43% unknown). The mean age ranged from 18 to 55 years, with 61% female and 39% male. Quality measures were chosen based on completeness of R/E data and were either process or outcomes focused. Statistically significant differences were noted after controlling for multiple comparisons. Discussion: The large proportion of missing or unknown R/E data and low overall rate of performance on these quality measures made the relevance of small differences difficult to determine. This analysis demonstrates the feasibility of using the Axon Registry to assess neurologic disparities in outpatient care. More education and training are required on the accurate capture of R/E data in the EHR.

Treating people where they are: Nurse-led micro-elimination of hepatitis C in supported housing sites for networks of people who inject drugs in Victoria, Canada.

To achieve the World Health Organization's goal of eliminating hepatitis C (HCV) by 2030 requires enhanced HCV testing and treatment among people who use drugs (PWUD). Micro-elimination of HCV is a strategy to target HCV testing and treatment efforts to specific segments of the population. From February to December 2018 nurses initiated a "seek & treat" micro-elimination approach, increasing outreach and removing barriers to accessing HCV treatment in a clinic setting by testing and treating individuals, including PWUD, where they live. The aim of this study was to evaluate the proportion of clients with HCV antibodies and HCV RNA and the response to direct acting agent (DAA therapy) among people who live at or have social connections to local supportive housing sites through this nurse-led micro-elimination project in Victoria, Canada. A chart review of electronic medical records and case management documentation was used to collect relevant data of participants treated with DAA therapy, identified through specific housing site testing and outreach interventions. In total, 180 people were tested for HCV antibodies, 72 (40%) were antibody positive: 51 (28%) were RNA positive, 13 (7%) had spontaneously cleared and 8 (4%) had been previously treated. Of the 51 that were currently living with HCV, 43 people were started on treatment, 39 have achieved sustained virologic response (SVR). By providing treatment to clients in their homes and with their friends, clinicians have been able to treat clients, including those with limited contact with the health care system.

Reinfection following successful direct-acting antiviral therapy for HCV infection among people attending an inner-city community health centre in Victoria, Canada.

BACKGROUND: Studies of HCV reinfection following direct-acting antiviral (DAA) therapy among PWID have been limited by short follow-up and small case numbers. This study evaluated the incidence of HCV reinfection following successful DAA therapy among people attending an inner-city community health centre in Victoria, Canada. METHODS: In this observational study, participants treated with DAA therapy between November 2014 and December 31, 2019 were included. Retrospective chart review was performed to assess demographics, recent injecting drug use at treatment initiation (previous six months), opioid agonist treatment (OAT), and HIV. Endpoints included sustained virologic response (SVR), HCV reinfection, and mortality. RESULTS: Of 482 participants initiating DAA treatment, 30% were female, 46% were receiving OAT, 49% had recent injection drug use, 15% had HIV/HCV coinfection, and 22% had cirrhosis. Treatment completion was 97% (468/482; 12 discontinued therapy, and 2 died during treatment). SVR was 87% (418/482). Outcomes among those who completed treatment but did not achieve SVR (n=53), included loss to follow-up (n=11), HCV RNA for SVR testing not completed (n=18), viral relapse (n=6), reinfection (n=5) and viral recurrence (n=5, unable to distinguish viral relapse from reinfection), and death (n=7). The rate of HCV reinfection was 3.6/100 person-years (95% confidence interval [CI] 2.4-5.5; 22 cases; 602 person-years follow-up). Factors associated with an increased risk of HCV reinfection included recent injection drug use (adjusted relative risk [aRR] 8.55, 95% CI 1.98-36.96) and HIV co-infection (aRR 2.35, 95% CI 1.01-5.44). Fifty-five people died (overdose, n=19) during (n=2) or following (n=53) therapy (7.4/100 person-years; 95% CI 5.6-9.6). CONCLUSION: This study demonstrates ongoing reinfection among a marginalized population at an inner-city community health centre, with higher rates among those with HIV and recent injecting drug use. The rates of reinfection and mortality highlight the importance of integrating HCV care with strategies to address drug-related harms.

Quality of Neurologic Care in the United States: Initial Report From the Axon Registry.

OBJECTIVE: To provide the initial description of the quality of outpatient US neurologic care as collected and reported in the Axon Registry. METHODS: We describe characteristics of registry participants and the performance of neurology providers on 20 of the 2019 Axon Registry quality measures. From the distribution of providers' scores on a quality measure, we calculate the median performance for each quality measure. We test for associations between quality measure performance, provider characteristics, and intrinsic measure parameters. RESULTS: There were 948 neurology providers who contributed a total of 6,480 provider-metric observations. Overall, the average quality measure performance score at the provider level was 66 (median 77). At the measure level (n = 20), the average quality measure performance score was 53 (median 55) with a range of 2 to 100 (interquartile range 20-91). Measures with a lower-complexity category (e.g., discrete orders, singular concepts) or developed through the specialty's qualified clinical data registry pathway had higher performance distributions. There was no difference in performance between Merit-Based Incentive Payment System (MIPS) and non-MIPS providers. There was no association between quality measure performance and practice size, measure clinical topic/neurologic condition, or measure year of entry. CONCLUSIONS: This cross-sectional assessment of quality measure performance in 2019 Axon Registry data demonstrates modest performance scores and considerable variability across measures and providers. More complex measures were associated with lower performance. These findings serve as a baseline assessment of quality of ambulatory neurologic care in the United States and provide insights into future measure design.

Exploring nurse-led HIV Pre-Exposure Prophylaxis in a community health care clinic.

OBJECTIVES: Gay, bisexual, and other men who have sex with men (gbMSM) are 131 times more likely to acquire HIV compared with other Canadian men. Pre-Exposure Prophylaxis (PrEP) for HIV has the potential to reduce or eliminate disparities in HIV acquisition among key affected populations. This paper aims to discuss the feasibility and utility of a nurse-led PrEP program administered by the Cool Aid Community Health Centre (CACHC) in Victoria, British Columbia as a public health PrEP program was initiated. DESIGN, SAMPLE AND MEASUREMENTS: A retrospective chart review of 124 gbMSM patients accessing PrEP at CACHC in 2018 collected information on patient demographics, STI testing results, and PrEP prescription pick-ups at 3 time points. RESULTS: Ninety-nine (79.8%) patients have continued on PrEP, as defined as having picked up their second 90-day PrEP prescription. Both older age and having an Sexually Transmitted Infection after PrEP enrolment were significantly associated with staying on PrEP; decreased risk perceptions contributed most to clinic-level discontinuance. Very few patients who stayed on PrEP have transitioned to their own General Practitioner. CONCLUSIONS: Patients appear to recognize their risk and are continuing on PrEP to reduce their risk of HIV. As evidenced by ability to recruit and maintain patients, we conclude that nurse-led PrEP at community health centres supports access and uptake of essential health services to optimize individual and population health.

Implementation of a data accuracy plan to improve data extraction yield in the Axon Registry®.

OBJECTIVE: To conduct a data quality improvement project to improve the quality measure data mapping and to measure key phrase logic in the Axon Registry.® METHODS: Prior validation analysis of the Axon Registry identified 2 main areas for remediation: methodology for mapping data from electronic health record (EHR) into the registry clinical data record (CDR) and key phrase logic for each measure. Practice groups participating in Axon Registry and 6 Axon Registry quality measures were selected for intervention. Mapping of measure elements and measure performances for each of the selected measures and practices were reviewed before intervention. The Data Accuracy Plan (DAP) was performed, and documentation data and visit data counts and data yield after intervention were calculated and analyzed. RESULTS: Documentation data and visit data counts and data yield increased for all 6 quality measures and all practices in the DAP. Increase in documentation data count ranged from 815 to 15,782 occurrences, while visit data count increase ranged from 519 to 16,383 visits. Average data yield range was 7.22% to 33.46% before intervention and increased to a range from 15.34% to 74.40% after intervention. CONCLUSION: There was substantial improvement in the accuracy of data extraction for quality measure elements after intervention to improve methodology for mapping EHR data into CDR and key phrase logic. Implementation of changes and continued review of data mapping and data dictionary are important to ensure accurate measure performance and to improve reliability and validity of Axon Registry data.

Direct-acting antiviral treatment for hepatitis C, reinfection and mortality among people attending an inner-city community health centre in Victoria, Canada.

BACKGROUND: Direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) has been shown to be effective among PWID, but more real-world data on treatment outcomes is needed. The aim of this analysis was to assess the efficacy of DAA therapy, and the rate of reinfection and mortality among people attending an inner-city community health centre in Victoria, Canada. METHODS: In this retrospective study, patients treated with DAA therapy between November 2014 and Dec 31, 2017 were included. Retrospective chart review was performed to assess recent injecting drug use (IDU, previous six months) or receipt of opioid agonist treatment (OAT). The primary endpoint was Sustained Virologic Response (SVR12). Secondary endpoints included HCV reinfection and mortality. RESULTS: Of 270 patients who initiated DAA treatment (31% female), 20% (n=54) had HIV/HCV coinfection, 32% (n=84) had cirrhosis, 67% (n=181) had genotype 1, 6% (n=15) had genotype 2, 26% (n=69) had genotype 3. 46% (n=125) of patients were receiving OAT and 49% (n=132) reported recent IDU. 98% (n=265) completed treatment; two people stopped due to mental health, two people died, and one was non-adherent. 92% (249 of 270) achieved SVR12. 16 patients with End of Treatment (EOT) response did not have a SVR12; 7 were lost to follow-up; 2 people refused bloodwork; 2 people died; 1 had reinfection; and 4 had viral relapse. There was no difference in SVR12 by OAT (OAT, 93% vs. no OAT, 91%, P=0.435), recent injecting drug use (yes, 92% vs. no, 92%, P=0.904), or HIV status (HIV, 92% vs. no HIV, 94%, P=0.498). Eight cases of HCV reinfection were observed over 253 person-years of follow up (3.2 cases per 100 person-years; 95% CI 1.6-6.3). Twenty people died (6.3 per 100 person-years; 95% CI 3.9-10.3), including two during therapy (drug overdose, n=2) and 18 following therapy completion (drug overdose, n=7). CONCLUSION: This study demonstrates that DAA treatment is effective among a marginalized population receiving care in an inner-city community health centre. The high mortality in this study highlights the importance of integrating HCV care within a framework addressing drug-related harms, preventing overdose mortality, addressing social inequalities, and improving the health of PWID.

Axon Registry® data validation: Accuracy assessment of data extraction and measure specification.

OBJECTIVE: To conduct a data validation study encompassing an accuracy assessment of the data extraction process for the Axon Registry®. METHODS: Data elements were abstracted from electronic health records (EHRs) by an external auditor (IQVIA) using virtual site visits at participating sites. IQVIA independently calculated Axon Registry quality measure performance rates based on American Academy of Neurology measure specifications and logic using Axon Registry data. Agreement between Axon Registry and IQVIA data elements and measure performance rates was calculated. Discordance was investigated to elucidate underlying systemic or idiosyncratic reasons for disagreement. RESULTS: Nine sites (n = 720 patients; n = 80 patients per site) with diversity among EHR vendor, practice settings, size, locations, and data transfer method were included. There was variable concordance between the data elements in the Axon Registry and those abstracted independently by IQVIA; high match rates (≥92%) were observed for discrete elements (e.g., demographics); lower match rates (<44%) were observed for elements with free text (e.g., plan of care). Across all measures, there was a 76% patient-level measure performance agreement between Axon Registry and IQVIA (κ = 0.53, p < 0.001). CONCLUSION: There was a range of concordance between data elements and quality measures in the Axon Registry and those independently abstracted and calculated by an independent vendor. Validation of data and processes is important for the Axon Registry as a clinical quality data registry that utilizes automated data extraction methods from the EHR. Implementation of remediation strategies to improve data accuracy will support the ability of the Axon Registry to perform accurate quality reporting.

Utilizing the Axon Registry® for quality improvement.

In 2015, the American Academy of Neurology began development of a clinical quality data registry now known as the Axon Registry®. The data collected by the Axon Registry and reported back to participants include performance on a number of quality measures relevant to neurology practice. While the Axon Registry may serve any number of needs for neurology practices, the essential function of the registry is to inform neurologists regarding the quality of their care and provide them with a tool to establish not only performance baselines but progress toward improved quality of care. This article includes 2 case studies of how the Axon Registry has been implemented in neurology practices to date. In the future, implementation of patient-reported outcome data and additional outcome measures will be necessary to expand the reach and effectiveness of the Axon Registry as a quality improvement tool.

EC144 is a potent inhibitor of the heat shock protein 90.

Alkyne 40, 5-(2-amino-4-chloro-7-((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)-7H-pyrrolo[2,3-d]pyrimidin-5-yl)-2-methylpent-4-yn-2-ol (EC144), is a second generation inhibitor of heat shock protein 90 (Hsp90) and is substantially more potent in vitro and in vivo than the first generation inhibitor 14 (BIIB021) that completed phase II clinical trials. Alkyne 40 is more potent than 14 in an Hsp90α binding assay (IC(50) = 1.1 vs 5.1 nM) as well as in its ability to degrade Her-2 in MCF-7 cells (EC(50) = 14 vs 38 nM). In a mouse model of gastric tumors (N87), 40 stops tumor growth at 5 mg/kg and causes partial tumor regressions at 10 mg/kg (po, qd × 5). Under the same conditions, 14 stops tumor growth only at 120 mg/kg, and does not induce partial regressions. Thus, alkyne 40 is approximately 20-fold more efficacious than 14 in mice.

Oncogenic MST1R activity in pancreatic and gastric cancer represents a valid target of HSP90 inhibitors.

AIM: To evaluate the effects of HSP90 blockade by EC154 on the oncogenic receptor tyrosine kinase macrophage-stimulating 1 receptor (MST1R) in gastric and pancreatic cancer. MATERIALS AND METHODS: Impact of EC154 on signaling pathways was investigated by western blotting. Cancer cell migration was evaluated in Boyden chambers. Transcriptional regulation of MST1R was examined by using promoter-luciferase reporter constructs. Effects on MST1R expression, and tumor growth were investigated in in vivo tumor models. RESULTS: MST1R was expressed by cancer cells without evidence of MST1R mutations. EC154 led to an effective inhibition of cancer cell growth, down-regulated MST1R, diminished its promoter activity, and disrupted oncogenic macrophage-stimulating protein 1 (MSP1) signaling. Moreover, pro-migratory activities of cancer cells were dramatically inhibited. In vivo, treatment with EC154 significantly reduced tumor growth, while MST1R expression was down-regulated. CONCLUSION: Wild-type MST1R is an HSP90 client protein that can be targeted in gastrointestinal cancer using HSP90 inhibitors.

Comparative analysis of novel and conventional Hsp90 inhibitors on HIF activity and angiogenic potential in clear cell renal cell carcinoma: implications for clinical evaluation.

BACKGROUND: Perturbing Hsp90 chaperone function targets hypoxia inducible factor (HIF) function in a von Hippel-Lindau (VHL) independent manner, and represents an approach to combat the contribution of HIF to cell renal carcinoma (CCRCC) progression. However, clinical trials with the prototypic Hsp90 inhibitor 17-AAG have been unsuccessful in halting the progression of advanced CCRCC. METHODS: Here we evaluated a novel next generation small molecule Hsp90 inhibitor, EC154, against HIF isoforms and HIF-driven molecular and functional endpoints. The effects of EC154 were compared to those of the prototypic Hsp90 inhibitor 17-AAG and the histone deacetylase (HDAC) inhibitor LBH589. RESULTS: The findings indicate that EC154 is a potent inhibitor of HIF, effective at doses 10-fold lower than 17-AAG. While EC154, 17-AAG and the histone deacetylase (HDAC) inhibitor LBH589 impaired HIF transcriptional activity, CCRCC cell motility, and angiogenesis; these effects did not correlate with their ability to diminish HIF protein expression. Further, our results illustrate the complexity of HIF targeting, in that although these agents suppressed HIF transcripts with differential dynamics, these effects were not predictive of drug efficacy in other relevant assays. CONCLUSIONS: We provide evidence for EC154 targeting of HIF in CCRCC and for LBH589 acting as a suppressor of both HIF-1 and HIF-2 activity. We also demonstrate that 17-AAG and EC154, but not LBH589, can restore endothelial barrier function, highlighting a potentially new clinical application for Hsp90 inhibitors. Finally, given the discordance between HIF activity and protein expression, we conclude that HIF expression is not a reliable surrogate for HIF activity. Taken together, our findings emphasize the need to incorporate an integrated approach in evaluating Hsp90 inhibitors within the context of HIF suppression.

Design, synthesis, and biological evaluation of pyrazolopyrimidine-sulfonamides as potent multiple-mitotic kinase (MMK) inhibitors (part I).

A novel class of pyrazolopyrimidine-sulfonamides was discovered as selective dual inhibitors of aurora kinase A (AKA) and cyclin-dependent kinase 1 (CDK1). These inhibitors were originally designed based on an early lead (compound I). SAR development has led to the discovery of potent inhibitors with single digit nM IC(50)s towards both AKA and CDK1. An exemplary compound 1a has demonstrated good efficacy in an HCT116 colon cancer xenograft model.

EC144, a synthetic inhibitor of heat shock protein 90, blocks innate and adaptive immune responses in models of inflammation and autoimmunity.

Heat shock protein 90 (Hsp90) is a molecular chaperone involved in folding and stabilizing multiple intracellular proteins that have roles in cell activation and proliferation. Many Hsp90 client proteins in tumor cells are mutated or overexpressed oncogenic proteins driving cancer cell growth, leading to the acceptance of Hsp90 as a potential therapeutic target for cancer. Because several signal transduction molecules that are dependent on Hsp90 function are also involved in activation of innate and adaptive cells of the immune system, we investigated the mechanism by which inhibiting Hsp90 leads to therapeutic efficacy in rodent models of inflammation and autoimmunity. EC144, a synthetic Hsp90 inhibitor, blocked LPS-induced TLR4 signaling in RAW 264.7 cells by inhibiting activation of ERK1/2, MEK1/2, JNK, and p38 MAPK but not NF-κB. Ex vivo LPS-stimulated CD11b(+) peritoneal exudate cells from EC144-treated mice were blocked from phosphorylating tumor progression locus 2, MEK1/2, and ERK1/2. Consequently, EC144-treated mice were resistant to LPS administration and had suppressed systemic TNF-α release. Inhibiting Hsp90 also blocked in vitro CD4(+) T cell proliferation in mouse and human MLRs. In vivo, semitherapeutic administration of EC144 blocked disease development in rat collagen-induced arthritis by suppressing the inflammatory response. In a mouse collagen-induced arthritis model, EC144 also suppressed disease development, which correlated with a suppressed Ag-specific Ab response and a block in activation of Ag-specific CD4(+) T cells. Our results describe mechanisms by which blocking Hsp90 function may be applicable to treatment of autoimmune diseases involving inflammation and activation of the adaptive immune response.

BIIB021, a novel Hsp90 inhibitor, sensitizes head and neck squamous cell carcinoma to radiotherapy.

Heat shock protein 90 (Hsp90) is a molecular chaperone that promotes the conformational maturation of numerous client proteins, many of which play critical roles in tumor cell growth and survival. The ansamycin-based Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) is currently in Phase III clinical testing. However, 17-AAG is difficult to formulate and associated with dose-limited toxicity issues. A fully synthetic and bioavailable Hsp90 inhibitor, BIIB021, was evaluated for antitumor activity in a variety of head and neck squamous cell carcinoma (HNSCC) cell lines and HNSCC xenograft models, either as a single agent or in combination with fractionated radiation and the results were compared with that of 17-AAG. BIIB021 showed strong antitumor activity, comparable with, and in certain instances, superior to 17-AAG. BIIB021 enhanced the in vitro radiosensitivity of HNSCCA cell lines with a corresponding reduction in the expression of key radioresponsive proteins, increased apoptotic cells and enhance G2 arrest. In xenograft studies, BIIB021 exhibited a strong antitumor effect outperforming 17-AAG, either as a single agent and or in combination with radiation, thereby improved the efficacy of radiation. These results suggest that this synthetic and bioavailable Hsp90 inhibitor affects multiple pathways involved in tumor development and progression in the HNSCC setting and may represent a better strategy for the treatment of HNSCC patients, either as a monotherapy or a radiosensitizer. Furthermore, it also demonstrates the benefits of using preclinical models of chemosensitization to radiotherapy to explore clinically relevant radiation dosing schemes.

An investigation into the potential use of serum Hsp70 as a novel tumour biomarker for Hsp90 inhibitors.

Hsp90 inhibitors are under investigation in multiple human clinical trials for the treatment of cancers, including myeloma, breast cancer, prostate, lung, melanoma, gastrointestinal stromal tumour and acute myeloid leukaemia. The pharmacodynamic activity of Hsp90 inhibitors in the clinic is currently assessed by Hsp70 induction in peripheral blood mononuclear cells using Western blot analysis, a method that is laborious, semiquantitative and difficult to implement in the clinic. Since Hsp70 was reported to be secreted by tumour cells and elevated in sera of cancer patients, serum Hsp70 has been evaluated as a potentially more robust, easily and reproducibly measured biomarker of Hsp90 inhibition as an alternative to cytosolic Hsp70. A highly sensitive and specific electrochemiluminescent ELISA was developed to measure serum Hsp70 and employed to evaluate Hsp70 levels in both ex vivo and xenograft samples. In ex vivo studies, maximal secretion of Hsp70 by tumour cells was observed between 48 and 72 h after exposure to Hsp90 inhibitors. In in vivo studies a 3-4-fold increase in serum Hsp70 was observed following treatment with BIIB021 in tumour-bearing mice. Strikingly, secreted Hsp70 was detectable in mice transplanted with human tumours but not in naive mice indicating a direct origination from the transplanted tumours. Analysis of clinical samples revealed low baseline levels (2 - 15 ng ml(-1)) of Hsp70 in the serum of cancer patients and normal donors. Together these findings in laboratory studies and archived cancer patient sera suggest that serum Hsp70 could be a novel biomarker to assess reliably the pharmacological effects of Hsp90 inhibitors in clinical trials, especially under conditions where collection of tumour biopsies is not feasible.