The importance of methods for site performance evaluation in REPRIEVE, a longitudinal, global, multicenter trial

BACKGROUND

REPRIEVE, the Randomized Trial to Prevent Vascular Events in HIV, is a multicenter, primary prevention trial evaluating whether a statin can prevent major cardiovascular events in people with HIV. REPRIEVE is conducted at >100 clinical research sites (CRSs) globally. Detailed, comprehensive, and novel methods for evaluating and communicating CRS performance are required to ensure trial integrity and data quality. In this analysis we describe a comprehensive multidimensional methodology for evaluating CRS performance.

METHODS

The REPRIEVE Data Coordinating and Clinical Coordinating Centers developed a robust system for evaluation of and communication with CRSs, designed to identify potential issues and obstacles to performance, provide real-time technical support, and make recommendations for process improvements to facilitate efficient trial execution. We describe these systems and evaluate their impact on participant retention, data management, and specimen management from 2019 to 2022, corresponding to the period from end of recruitment to present. This evaluation was based on pre-defined metrics, regular reviews, and bidirectional communication.

RESULTS

Participant retention, data management, and specimen management all remained steady over the three-year period, although metrics varied by country of enrollment. Targeted messaging relating to certain performance metrics was effective.

CONCLUSION

Site performance is vital to ensure trial integrity and achievement of key trial goals. This analysis demonstrates that utilization of a comprehensive approach allows for a thorough evaluation of CRS performance, facilitates data and specimen management, and enhances participant retention. Our approach may serve as a guidepost for maximizing future large-scale clinical trials' operational success and scientific rigor.

CLINICALTRIALS

gov Identifier: NCT02344290.

2358. Dementia and Cognitive Concerns are Risk Factors for Mortality in People with Human Immunodeficiency Virus and COVID-19

Background

Despite higher prevalence of cognitive disorders in people with human immunodeficiency virus (PWH) and dementia being a risk factor for COVID-19 mortality, the association between dementia and adverse outcomes in PWH with COVID-19 has not been well established.

Methods

This was a matched case-control study (1:10) of patients with and without HIV at an academic institution with documented SARS-CoV-2 polymerase chain reaction (PCR) positivity from March 2020-March 2021. Data were extracted from the electronic health record data registry. PWH were matched to people without HIV (PWoH) by age, sex, race, and zip code. The primary exposures were dementia (identified using International Classification of Diseases, Tenth Revision codes) and cognitive concerns, defined as documentation of possible cognitive impairment up to 12 months prior to COVID-19 diagnosis and ascertained using a semi-automated natural language processing annotation tool. VACS 2.0 Index (including age, sex, body mass index, CD4+ T-cell count and HIV-1 RNA) was calculated. Logistic regression models assessed the effect of dementia and cognitive concerns on the odds of death (OR [95% confidence interval]), adjusted for VACS 2.0 Index.

Results

Sixty-four (0.45%) PWH were identified among 14129 patients with COVID-19 and were matched to 463 PWoH. Among PWH, 59% were virally suppressed, and 14% had CD4< 200 cells/μL. Compared to 463 matched PWoH, PWH had higher prevalence of dementia (16% vs. 6%, p=0.01) and cognitive concerns (22% vs. 16%, p=0.04). Death was more frequent in PWH (17% vs. 6%, p< 0.01) and at younger ages (58 vs. 66 years, p=0.03). Cognitive concerns (2.5 [1.1–5.9], p=0.03) and dementia (3.4 [1.3–8.1], p=0.01) were significantly associated with increased adjusted odds of death in the overall group. Among PWH, cognitive concerns (7.2 [1.1–48], p=0.04) and dementia (6.0 [0.8–43.8], p=0.08) remained associated with mortality.

Conclusion

Dementia and cognitive concerns were associated with mortality among PWH with COVID-19. The magnitude of the effect of cognitive impairment on COVID-19 outcomes may be greater in HIV, and additional studies with larger cohorts will help to assess this association further. Assessment of cognitive status is an important component to care for aging PWH in the COVID-19 era.

Disclosures

All Authors: No reported disclosures.

0209 The Effect of Time of Day of COVID-19 Vaccination and other Covariates on Side Effects

Introduction

Circadian rhythms have critical roles in human health. We quantified the effect of time-of-day of COVID-19 vaccination and other covariates on self-reported side effects post vaccination.

Methods

The dataset was created from MassGeneralBrigham (MGB) electronic health records and REDCap survey that collected self-reported symptoms for 1-3 days after each immunization. Variables are demographics (age, sex, race, and ethnicity), vaccine manufacturer, clock time of vaccine administration/appointment, any COVID-19 diagnosis/positive test prior to vaccination, any history of allergy, and any note of epinephrine self-injection (e.g., EpiPen) medication. Time of day groupings were morning (6 am–10 am), midday (10 am–2 pm), late afternoon (2 pm–6 pm) or evening (6 pm–10 pm). Side effects were classified as Allergic (Rash; Hives; Swollen lips, tongue, eyes, or face; Wheezing) and Non-Allergic (New Headache, New Fatigue, Arthralgias, Myalgias, Fever) symptoms. The study was approved by the MGB IRB.Machine learning (ML) techniques (e.g., extreme gradient boosting) were applied to the variables to predict the occurrence of side effects. Stratified k-fold cross validation was used to validate the performance of the ML models. Shapley Additive Explanation values were computed to explain the contribution of each of the variables to the prediction of the occurrence of side effects.

Results

Data were from 54,844 individuals. On day 1 after the first vaccination, (i) females, people who received the Moderna vaccine, and those with any allergy history were more likely to report Allergic side effects; and (ii) females, people who received the Janssen vaccine, those who had prior COVID-19 diagnosis ,and those who received their vaccine in the morning or midday and were more likely to report Non-Allergic symptoms. Older persons had fewer side effects of any type.

Conclusion

ML techniques identified demographic and time-of-day-of-vaccination effects on side effects reported on the first day after the first dose of a COVID-19 vaccination. We will use these techniques to test for changes on days 2 and 3 after the first dose, and the first 3 days after the second dose and for the influence of recent night or shiftwork. Future work should target underlying physiological reasons.

Support (If Any)

 

A minimal monitoring approach for the treatment of hepatitis C virus infection (ACTG A5360 [MINMON]): a phase 4, open-label, single-arm trial

BACKGROUND

Despite widespread availability of direct-acting antivirals including generic formulations, limited progress has been made in the global adoption of hepatitis C virus (HCV) treatment. Barriers to treatment scale-up include availability and access to diagnostic and monitoring tests, health-care infrastructure, and requirement for frequent visits during treatment.

METHODS

ACTG A5360 was a phase 4, open-label, single-arm trial across 38 sites in Brazil, South Africa, Thailand, Uganda, and the USA. Key inclusion criteria were age of 18 years or older, evidence of active HCV infection (HCV RNA >1000 IU/mL) and HCV treatment-naive; patients with compensated cirrhosis and HIV/HCV co-infection were included but their enrolment was capped. All participants received a fixed dose combination of oral sofosbuvir (400 mg) and velpatasvir (100 mg) once daily for 12 weeks. The minimal monitoring (MINMON) approach consisted of four components: (1) there was no pre-treatment genotyping; (2) the entire treatment course (84 tablets) was dispensed at entry; (3) there were no scheduled visits or laboratory monitoring; and (4) there were two points of remote contact, at week 4 for adherence and week 22, to schedule outcome assessment at week 24 (-2 weeks to +4 weeks). Participants who missed the week 24 window could return for a visit to assess treatment response any time before week 72. Unplanned visits for any reason were permissible before the week 24 visit. The primary efficacy outcome was sustained virological response (SVR), defined as HCV RNA less than the lower limit of quantification measured at least 22 weeks post-treatment initiation; the primary safety outcome was serious adverse events. The primary efficacy analysis included all participants who initiated treatment, using a missing=failure approach. The primary safety analysis included all participants who initiated treatment and had at least one post-treatment assessment. This trial is registered at ClinicalTrials.gov, NCT03512210.

FINDINGS

Between Oct 22, 2018, and July 19, 2019, 400 participants were enrolled across all 38 sites; 399 initiated treatment. At the SVR assessment visit, 355 (89%) of 397 participants reported taking 100% of the trial medication during the 12-week treatment period; two patients did not have any follow-up visits after the entry visit and were excluded from the safety analyses. Overall, 379 of the 399 who initiated treatment had an SVR (95·0%, 95% CI 92·4-96·7). 14 (4%) of 397 participants reported serious adverse events between treatment initiation and week 28; none were treatment related or led to treatment discontinuation or death. 15 (4%) of 399 participants had unplanned visits; none were related to treatment.

INTERPRETATION

In this diverse global population of people with HCV, the MINMON approach with sofosbuvir-velpatasvir treatment was safe and achieved SVR comparable to standard monitoring observed in real-world data. Coupled with innovative case finding strategies, this strategy could be crucial to the global HCV elimination agenda.

FUNDING

US National Institutes of Health and Gilead Sciences.

MXene-infused bioelectronic interfaces for multiscale electrophysiology and stimulation

Soft bioelectronic interfaces for mapping and modulating excitable networks at high resolution and at large scale can enable paradigm-shifting diagnostics, monitoring, and treatment strategies. Yet, current technologies largely rely on materials and fabrication schemes that are expensive, do not scale, and critically limit the maximum attainable resolution and coverage. Solution processing is a cost-effective manufacturing alternative, but biocompatible conductive inks matching the performance of conventional metals are lacking. Here, we introduce MXtrodes, a class of soft, high-resolution, large-scale bioelectronic interfaces enabled by Ti3C2 MXene (a two-dimensional transition metal carbide nanomaterial) and scalable solution processing. We show that the electrochemical properties of MXtrodes exceed those of conventional materials and do not require conductive gels when used in epidermal electronics. Furthermore, we validate MXtrodes in applications ranging from mapping large-scale neuromuscular networks in humans to cortical neural recording and microstimulation in swine and rodent models. Last, we demonstrate that MXtrodes are compatible with standard clinical neuroimaging modalities.

Development and Prospective Validation of a Transparent Deep Learning Algorithm for Predicting Need for Mechanical Ventilation

IMPORTANCE

Objective and early identification of hospitalized patients, and particularly those with novel coronavirus disease 2019 (COVID-19), who may require mechanical ventilation is of great importance and may aid in delivering timely treatment.

OBJECTIVE

To develop, externally validate and prospectively test a transparent deep learning algorithm for predicting 24 hours in advance the need for mechanical ventilation in hospitalized patients and those with COVID-19.

DESIGN

Observational cohort study SETTING: Two academic medical centers from January 01, 2016 to December 31, 2019 (Retrospective cohorts) and February 10, 2020 to May 4, 2020 (Prospective cohorts).

PARTICIPANTS

Over 31,000 admissions to the intensive care units (ICUs) at two hospitals. Additionally, 777 patients with COVID-19 patients were used for prospective validation. Patients who were placed on mechanical ventilation within four hours of their admission were excluded. MAIN OUTCOME(S) and MEASURE(S): Electronic health record (EHR) data were extracted on an hourly basis, and a set of 40 features were calculated and passed to an interpretable deep-learning algorithm to predict the future need for mechanical ventilation 24 hours in advance. Additionally, commonly used clinical criteria (based on heart rate, oxygen saturation, respiratory rate, FiO2 and pH) was used to assess future need for mechanical ventilation. Performance of the algorithms were evaluated using the area under receiver-operating characteristic curve (AUC), sensitivity, specificity and positive predictive value.

RESULTS

After applying exclusion criteria, the external validation cohort included 3,888 general ICU and 402 COVID-19 patients. The performance of the model (AUC) with a 24-hour prediction horizon at the validation site was 0.882 for the general ICU population and 0.918 for patients with COVID-19. In comparison, commonly used clinical criteria and the ROX score achieved AUCs in the range of 0.773 - 0.782 and 0.768 - 0.810 for the general ICU population and patients with COVID-19, respectively.

CONCLUSIONS AND RELEVANCE

A generalizable and transparent deep-learning algorithm improves on traditional clinical criteria to predict the need for mechanical ventilation in hospitalized patients, including those with COVID-19. Such an algorithm may help clinicians with optimizing timing of tracheal intubation, better allocation of mechanical ventilation resources and staff, and improve patient care.

1008 Brain Age Based on Sleep Encephalography is Elevated in HIV+ Adults on ART

Introduction

Sleep EEG is a promising tool to measure brain aging in vulnerable populations such as people with HIV, who are high risk of brain aging due to co-morbidities, increased inflammation, and antiretroviral neurotoxicity. Our lab previously developed a machine learning model that estimates age from sleep EEG (brain age, BA), which reliably predicts chronological age (CA) in healthy adults. The difference between BA and CA, the brain age index (BAI), independently predicts mortality, and is increased by cardiovascular co-morbidities. Here, we assessed BAI in HIV+ compared to matched HIV- adults.

Methods

Sleep EEGs from 43 treated HIV+ adults were gathered and matched to controls (HIV-, n=284) by age, gender, race, alcoholism, smoking and substance use history. We compared BAI between groups and used additional causal interference methods to ensure robustness. Individual EEG features that underlie BA prediction were also compared. We performed a sub-analysis of BAI between HIV+ with or without a history of AIDS.

Results

After matching, mean CA of HIV+ vs HIV- adults were 49 and 48 years, respectively (n.s.). The mean HIV+ BAI was 3.04 years higher than HIV- (4.4 vs 1.4 yr; p=0.048). We found consistent and significant results with alternative causal inference methods. Several EEG features predictive of BA were different in the HIV+ and HIV- cohorts. Most notably, non-REM stage 2 sleep (N2) delta power (1-4Hz) was decreased in HIV+ vs. HIV- adults, while theta (4-8Hz) and alpha (8-12Hz) power were increased. Those with AIDS (n=19, BAI=4.40) did not have significantly different BAI than HIV+ without AIDS (n=23, BAI=5.22). HIV+ subjects had higher rates of insomnia (56% vs 29%, p<0.001), obstructive apnea (47% vs 30%, p=0.03), depression (49% vs 23%, p<0.001), and bipolar disorder (19% vs 4%, p<0.001).

Conclusion

HIV+ individuals on ART have excess sleep-EEG based brain age compared to matched controls. This excess brain age is partially due to reduction in delta power during N2, suggesting decreased sleep depth. These results suggest sleep EEG could be a valuable brain aging biomarker for the HIV population.

Support

This research is supported by the Harvard Center for AIDS Research HU CFAR NIH/NIAID 5P30AI060354-16.

Effects of statin therapy on coronary artery plaque volume and high-risk plaque morphology in HIV-infected patients with subclinical atherosclerosis: a randomised, double-blind, placebo-controlled trial

BACKGROUND

HIV-infected patients have a high risk of myocardial infarction. We aimed to assess the ability of statin treatment to reduce arterial inflammation and achieve regression of coronary atherosclerosis in this population.

METHODS

In a randomised, double-blind, placebo-controlled trial, 40 HIV-infected participants with subclinical coronary atherosclerosis, evidence of arterial inflammation in the aorta by fluorodeoxyglucose (FDG)-PET, and LDL-cholesterol concentration of less than 3.37 mmol/L (130 mg/dL) were randomly assigned (1:1) to 1 year of treatment with atorvastatin or placebo. Randomisation was by the Massachusetts General Hospital (MGH) Clinical Research Pharmacy with a permuted-block algorithm, stratified by sex with a fixed block size of four. Study codes were available only to the MGH Research Pharmacy and not to study investigators or participants. The prespecified primary endpoint was arterial inflammation as assessed by FDG-PET of the aorta. Additional prespecified endpoints were non-calcified and calcified plaque measures and high risk plaque features assessed with coronary CT angiography and biochemical measures. Analysis was done by intention to treat with all available data and without imputation for missing data. The trial is registered with ClinicalTrials.gov, number NCT00965185.

FINDINGS

The study was done from Nov 13, 2009, to Jan 13, 2014. 19 patients were assigned to atorvastatin and 21 to placebo. 37 (93%) of 40 participants completed the study, with equivalent discontinuation rates in both groups. Baseline characteristics were similar between groups. After 12 months, change in FDG-PET uptake of the most diseased segment of the aorta was not different between atorvastatin and placebo, but technically adequate results comparing longitudinal changes in identical regions could be assessed in only 21 patients (atorvastatin Δ -0.03, 95% CI -0.17 to 0.12, vs placebo Δ -0.06, -0.25 to 0.13; p=0.77). Change in plaque could be assessed in all 37 people completing the study. Atorvastatin reduced non-calcified coronary plaque volume relative to placebo: median change -19.4% (IQR -39.2 to 9.3) versus 20.4% (-7.1 to 94.4; p=0.009, n=37). The number of high-risk plaques was significantly reduced in the atorvastatin group compared with the placebo group: change in number of low attenuation plaques -0.2 (95% CI -0.6 to 0.2) versus 0.4 (0.0, 0.7; p=0.03; n=37); and change in number of positively remodelled plaques -0.2 (-0.4 to 0.1) versus 0.4 (-0.1 to 0.8; p=0.04; n=37). Direct LDL-cholesterol (-1.00 mmol/L, 95% CI -1.38 to 0.61 vs 0.30 mmol/L, 0.04 to 0.55, p<0.0001) and lipoprotein-associated phospholipase A2 (-52.2 ng/mL, 95% CI -70.4 to -34.0, vs -13.3 ng/mL, -32.8 to 6.2; p=0.005; n=37) decreased significantly with atorvastatin relative to placebo. Statin therapy was well tolerated, with a low incidence of clinical adverse events.

INTERPRETATION

No significant effects of statin therapy on arterial inflammation of the aorta were seen as measured by FDG-PET. However, statin therapy reduced non-calcified plaque volume and high-risk coronary plaque features in HIV-infected patients. Further studies should assess whether reduction in high-risk coronary artery disease translates into effective prevention of cardiovascular events in this at-risk population.

FUNDING

National Institutes of Health, Harvard Clinical and Translational Science Center, National Center for Research Resources.

Higher expression of several interferon-stimulated genes in HIV-1-infected females after adjusting for the level of viral replication (P3039)

Background. Clinical studies have shown faster disease progression and stronger immune activation in HIV-1-infected females as compared to males for the same level of HIV-1 replication. This study assesses whether the elevated levels of HIV-1-induced IFN-α production observed in females were associated with higher interferon-stimulated gene expression levels in T cells, and hence suggesting type-I-IFN as a mechanism for the higher HIV-1-associated immune activation observed. Methods. Fluorescence activated cell sorting was used to isolate T cells and dendritic cells from PBMCs of treatment-naïve chronically HIV-1-infected individuals enrolled in ACTG 384. The expression of 98 genes involved in toll-like receptor and type-I-IFN signaling pathways were quantified using Nanostring technology on sorted cell populations. Results. Several interferon-stimulated genes were significantly correlated with HIV-1 viral load and/or CD4+ T cell count. Higher expression levels of a subset of these interferon-stimulated genes were observed in cells derived from females compared to males after adjusting for viral load, and were correlated to higher levels of T cell activation. Conclusion. These data show that higher IFN-α production and resulting higher ex vivo expression of several interferon-stimulated genes in females can contribute to higher levels of immune activation, and subsequently the observed faster HIV-1 disease progression in females for a given level of viral replication.

Molecular mechanism for pre-B cell loss in mutant rabbits (153.17)

VH4 is the most frequently rearranged VH gene during B cell development in mutant ali/ali rabbits; however, most VH4-utilizing cells do not survive the pre-B cell stage. The mechanism(s) by which these pre-B cells are lost remains an enigma. We hypothesize that VH4-utilzing pre-B cells are lost due to inefficient pre-BCR formation and inadequate pre-BCR signaling. Ex-vivo cultures of ali/ali bone marrow cells on OP9 stroma yield fewer blasting pre-B cells and reduced levels of phosphorylated-Syk than cultures of wildtype(wt) controls, suggesting that VH4-utilzing pre-BCRs have impaired signaling. We previously determined that pre-BCRs containing VH4-μ chains are less abundant on the cell surface compared to the pre-BCRs containing VH1-μ chains as are found in wt rabbits. A single amino acid substitution in FR2 of VH4(Y47W)restored the levels of cell surface pre-BCR expression to that of wt pre-BCR, and current studies are testing if this substitution is sufficient to restore pre-BCR cell signaling and pre-B cell development. Loss of VH4-utilizing pre-B cells is not likely due to gross structural defects in VH4-μ chains since the conventional BCRs utilizing VH4 are both functional and diverse. Therefore, studies utilizing the ali/ali rabbit offer a unique model system to identify necessary amino acids for pre-BCR formation and signaling.

Abstract A20: Evidences that GPR43, a G-protein-coupled receptor for short chain fatty acids, suppresses colon cancer

GPR43 is a G protein-coupled receptor for short chain fatty acids (SCFAs). Expression of GPR43 is detected in hematopoietic tissues and the large intestine. SCFAs are derived from bacterial fermentation and metabolism of undigested dietary fibers and have been recognized for their cancer prevention activities in the colon. The role of SCFAs, particularly butyrate, in colon cancer therapy has been extensively studied, and its tumor suppressive functions are believed to be due to their intracellular actions, notably inhibition of histone deacetylase. In this study, we show that SCFAs also exert their anti-tumor effects via receptor GPR43 and that GPR43 is frequently lost in colon cancer cells. Immunohistostaining revealed that GPR43 immunoreactivity was high in normal colon tissues (N=31) but was markedly reduced or completely lost in most colorectal adenocarcinoma tissues (N=70) and their corresponding lymph node metastatic adenocarcinomas (N =38). RT-PCR analysis detected the presence of full length GPR43 mRNA in only one (HT-29) out of nine established human colon cancer cell lines. Restoration of GPR43 expression in HCT8 human colonic adenocarcinoma cells induced G0/G1 cell cycle arrest and activated caspases, leading to increased apoptotic cell death after propionate/butyrate treatment. Restored GPR43 expression, coupled with propionate treatment, induced an upregulation of p21 and a decrease in the levels of cyclin D3 and cyclin-dependent kinases (CDKs) 1 and 2, while the CDK4 and CDK6 levels remained unchanged. Our results suggest that GPR43 functions as a tumor suppressor by mediating SCFA-induced cell proliferation inhibition and apoptotic cell death in colon cancer.

Citation Information: Cancer Prev Res 2010;3(12 Suppl):A20.

Molecular Basis for Loss of VH4-encoded pre-B cells in Mutant Rabbits (36.7)

Developing B cells in mutant ali/ali rabbits predominantly utilize VH4 during VDJ gene rearrangement. However, most of the VH4-utilizing B cells encounter a severe developmental block at the pre-B cell stage. In contrast, wildtype rabbit B cells predominantly rearrange VH1, a gene &gt;90% identical to VH4, and develop normally. We seek to determine how these nearly identical VH genes have profoundly different effects on B cell development. We hypothesize that VH4-utilizing cells are blocked at the pre-B stage due to weak interaction of the μ-chain with surrogate light chain (SL). We expressed VH4-utilizing μ-chains in a pro-B cell line that expresses SL and found that VH4-encoded μ-chains exhibit a 2 fold reduction in preBCR surface localization compared to control VH1-encoded μ-chains. Remarkably, a single amino acid substitution in VH4-framework region 2 (FR2) from tyrosine to an evolutionarily conserved tryptophan, found in VH1 and most VH genes of other species, restored surface preBCR expression. We are testing if this tryptophan substitution in FR2 of VH4 is sufficient to rescue pre-B cell development. These studies should identify evolutionarily conserved VH structural regions required for efficient preBCR formation and B cell development.

An open-label, multicenter, phase II study of AT-101 in combination with rituximab (R) in patients with untreated, grade 1-2, follicular non-Hodgkin's lymphoma (FL)

8582

Background: Bcl-2 family proteins are overexpressed in the majority of patients with FL and contribute to resistance to therapy. AT-101 is a pan-Bcl-2 inhibitor (Bcl-2, Bcl-XL, Bcl-W, and Mcl-1) and potent inducer of proapoptotic proteins. It is active as a single agent and in combination with R in NHL tumor models. Methods: Patients with untreated FL who did not require immediate chemotherapy were eligible. Treatment consisted of an induction cycle of AT-101 (30mg po daily × 21) and R (375 mg/m2 weekly × 4) followed by up to 4 maintenance cycles of AT-101 (30mg po daily × 21) and R (375 mg/m2) every 8 weeks in nonprogressors. Endpoints evaluated the response rate (RR) at week 8 (primary), overall response rate (ORR), molecular response rate (BCL-2JH rearrangement in blood and bone marrow), and safety of the combination. A mini-Max, 2-stage design (52 pts planned) was used to detect >70% RR with power of 90% and alpha of 0.10. Results: 23 pts enrolled: median age 64 yrs; FLIPI 0–5: 0%/17%/65%/13%/4%; Grade 1/2: 61%/39%; bulky disease (>5cm3): 35%; stage: 1–4 4%/4%/30%/61%; bone marrow + 48%. All pts received induction and 18 pts received 1 or more maintenance cycles. RR following induction was 26% (95%CI=10.2–48.4), 4% CR and the best ORR was 70% (95%CI=47.1–86.8), 35% CR. Molecular response analysis is ongoing. Grade 3/4 AEs that occurred in ≥2 pts: nausea 4(17%), vomiting 2(9%), abdominal pain 2(9%), fatigue 2(9%), and small bowel obstruction 2(9%). AT-101 was reduced to 20mg daily x 21 which improved GI tolerability. Conclusions: The combination of AT-101 and R was well tolerated. The week 8 RR did not meet statistical criteria to enroll stage II. The best ORR is at the upper limit of reported ORR for R alone; therefore a randomized trial is required to definitively determine activity of the combination.

[Table: see text]

Triplate fixation

Massive endoprostheses using a cemented intramedullary stem are widely used to allow early resumption of activity after surgery for tumours. The survival of the prosthesis varies with the anatomical site, the type of prosthesis and the mode of fixation. Revision surgery is required in many cases because of aseptic loosening. Insertion of a second cemented endoprosthesis may be difficult because of the poor quality of the remaining bone, and loosening recurs quickly.

We describe a series of 14 patients with triplate fixation in difficult revision or joint-sparing tumour surgery with a minimum follow-up of four years. The triplate design incorporated well within a remodelled cortex to achieve osseomechanical integration with all patients regaining their original level of function within five months.

Our preliminary results suggest that this technique may provide an easy, biomechanically friendly alternative to insertion of a further device with an intramedullary stem, which has a shorter lifespan in revision or joint-sparing tumour surgery. A short segment of bone remaining after resection of a tumour will not accept an intramedullary stem, but may be soundly fixed using this method.

Analysis of successful immune responses in persons infected with hepatitis C virus

Although hepatitis C virus (HCV) infection is very common, identification of patients during acute infection is rare. Consequently, little is known about the immune response during this critical stage of the disease. We analyzed the T lymphocyte response during and after acute resolving HCV infection in three persons, using interferon (IFN)-gamma enzyme-linked immunospot (ELISPOT) and human histocompatibility leukocyte antigen (HLA) peptide tetramer assays. Acute infection was associated with a broadly directed T helper and cytotoxic T lymphocyte (CTL) response, which persisted after resolution of clinical hepatitis and clearance of viremia. At the earliest time point studied, highly activated CTL populations were observed that temporarily failed to secrete IFN-gamma, a "stunned" phenotype, from which they recovered as viremia declined. In long-term HCV-seropositive persons, CTL responses were more common in persons who had cleared viremia compared with those with persistent viremia, although the frequencies of HCV-specific CTLs were lower than those found in persons during and after resolution of acute HCV infection. These studies demonstrate a strong and persistent CTL response in resolving acute HCV infection, and provide rationale to explore immune augmentation as a therapeutic intervention in chronic HCV infection.

Factors affecting the severity of motor vehicle traffic crashes involving elderly drivers in Ontario

A population-based cross-sectional study was conducted to examine factors affecting the severity of motor vehicle traffic crashes (MVTCs) involving elderly drivers in Ontario. The study population included drivers aged 65 and over involved in injury-producing MVTCs between 1988 and 1993 on Ontario public roads. Information was obtained from the Canadian Traffic Accident Information Databank (TRAID) compiled from police reports. The severity of MVTC was classified as fatal, major, minor or minimal. Comparisons between fatal-, major-, minor- and minimal-injury crashes were conducted. Percentage distributions of crashes at each level of severity involving elderly drivers were examined according to specific factors and tested using the X2 test. Multivariate unconditional logistic regression was used to calculate the estimated relative risk as odds ratios (ORs) while controlling for confounding factors. A number of factors were significantly related to the increased risk of fatal-injury in crashes compared with a reference category for each variable. These included age (OR = 1.4 for 70-79 and OR = 2.3 for 80 + ), sex (OR = 1.4 for males), failing to yield right-of-way/disobeying traffic signs (OR = 1.7), non-use of seat belts (OR = 4.0), ejection from vehicle (OR = 11.3), intersection without traffic controls (OR = 1.7), roads with higher speed limits (OR = 7.9 for 70-90 km/h; OR= 5.8 for 100 km/h), snowy weather (OR= 1.6), head-on collisions (OR=55.1), two-vehicle turning collisions (OR = 3.1 for left-turn, OR = 8.7 for right-turn), overtaking (OR = 5.6), and changing lanes (OR = 2.1). Adverse medical/physical conditions increased the risk of fatality by a factor of 5 for drivers 75-79 years of age and a factor of 3.5 for those 80 years and over. However, in the age group 65-74, medical/physical condition did not appear to be related to risk of fatality. Similar but weaker associations between these factors and risk of major- and minor-injury in crashes were also observed. To reduce the severity of crashes involving elderly drivers, strategies could target specific factors such as head-on collisions, single-vehicle collisions, and traffic controls at intersections. Driver conditions such as medical/physical conditions and driver actions such as failing to yield right-of-way/disobeying traffic signs should be examined further.

Characterization of HIV-1-specific T-helper cells in acute and chronic infection

HIV-1 infection is associated with progressive and relentless destruction of the immune system in the majority of infected persons, but some persons appear to be able to successfully contain the virus in the absence of antiviral therapy. Such cases suggest that the host immune response can successfully contain the virus, and provide the rationale for concerted efforts to understand the host immune response to the virus and to develop new strategies to combat the infection with immune based therapies. Historically, the greatest hole in the immune repertoire in HIV-1 infection has been the lack of strong virus-specific proliferative responses. However, new studies have identified a potent Th cell response in some infected persons, and have shown a statistically significant negative correlation between plasma viremia and virus-specific CD4 T-helper cells directed at the p24 protein. Moreover, early institution of potent antiviral therapy in the earliest stages of acute HIV-1 infection have led to persistent, strong HIV-1-specific T-helper cell responses, analogous to those seen in persons who are able to control viremia in the absence of antiviral therapy. We hypothesize that this is because potent antiviral therapy is able to protect virus-specific Th cells as they become activated, and thus these cells are not lost in the earliest stages of infection.

Factors affecting the severity of motor vehicle traffic crashes involving young drivers in Ontario

OBJECTIVES

To assess the factors affecting the severity of motor vehicles traffic crashes involving young drivers in Ontario.

POPULATION

Ontario young drivers, aged 16 to 20, involved in traffic crashes resulting in injury, between 1 January 1988 and 31 December 1993, on public roads in Ontario.

METHODS

Population based case-control study. Cases were fatal injury, major injury, and minor injury crashes involving young drivers. Controls were minimal injury crashes involving young drivers. Cases and controls were obtained retrospectively from the Canadian Traffic Accident Information Databank. Unconditional logistic regression was used for data analysis.

RESULTS

Factors significantly increasing the risk of fatal injury crashes include: drinking and driving (odds ratio (OR) 2.3), impairment by alcohol (OR 4.8), exceeding speed limits (OR 2.8), not using seat belts (OR 4.7), full ejection from vehicle (OR 21.3), intersection without traffic control (OR 2.2), bridge or tunnel (OR 4.1), road with speed limit 70-90 km/hour (OR 5.6) or 100 km/hour (OR 5.4), bad weather (OR 1.6), head-on collision (OR 80.0), and overtaking (OR 1.9). Results of the same model applied to major and minor injury crashes demonstrated consistent but weaker associations with decreasing levels of crash severity.

CONCLUSIONS

A casual relationship between crash severity and the risk factors listed above was proposed. Risk factors recommended for preventive intervention include: alcohol consumption, speeding, and use of seat belts. Head-on collisions are of primary concern.

A study of autologous blood collected after joint replacement surgery

Blood from the surgical drains of 11 patients undergoing joint replacement was collected in the Solcotrans Orthopaedic autologous transfusion device and analysed for microparticulate matter before and after micro-aggregate filtration and for its effect on the coagulation of paired venous blood samples. An average of 165 ml (range 0-260 ml) was collected into the Solcotrans during the first hour. Using a Coulter Counter Zm particle counter, particulate matter of diameter 10-20 microns was found in only 2 of 10 collections at an average concentration of 33 x 10(3)/l. All units contained acoagulable blood [kaolin partial thromboplastin time (KPTT) greater than 600 s] but when mixed with paired post-operative venous samples exhibited the ability to shorten the KPTT by an average of 4.3 s inspite of the marked dilutional effect of mixing. Retransfusion of blood collected in the Solcotrans Orthopaedic device appears to be a suitable method to supplement or substitute pre-deposit and reduce exposure to homologous blood. Given the low incidence and concentration of microparticles detected, retransfusion of shed blood by this method is unlikely to cause significant pulmonary vascular occlusion resulting directly from deposition of microparticles.

Challenging official health cost estimates: an alternative view that incorporates the behavioural and economic effects of policy changes

Cost estimates of health care policy changes are extremely important. Historically, however, the US government has done a poor job in projecting the actual cost of new health care programmes. These projections have been inaccurate primarily because government forecasters use 'static' methods that fail to incorporate the change in people's behaviour as a direct result of a new policy. In contrast, 'dynamic' forecasts incorporate the behavioural effects of policy changes on individuals and the economy. Static and dynamic estimates can lead to different results for 4 areas of US health policy: (a) the Medicare Catastrophic Coverage Act; (b) mandated health benefits; (c) health insurance tax subsidies; and (d) national health insurance. Improving health care policy requires the adoption of dynamic estimation practices, periodic appraisals evaluating the accuracy of official estimates in relation to actual experience, and clear presentation of proposed policy changes and estimates to policymakers and the general public.

Diagnostic assessment of macrophage phenotypes in cardiac transplant biopsies

Forty-one endomyocardial biopsies of the right interventricular septum have been investigated in 24 immunosuppressed patients after orthotopic heart transplantation. Monoclonal antibodies 27E10, 25F9, and RM3/1, which react with different macrophage phenotypes, and antisera MRP-8 and MRP-14, specific for proteins expressed on endothelial and monocyte cell surfaces in inflammation as well as markers for CD4+ and CD8+ T-lymphocytes, were employed in an indirect immunoperoxidase staining technique. This methodology permits more physiological recognition of the inflammatory process within the myocardium. It was possible to verify and to distinguish acute early, late and down-regulatory stages of inflammation in 33 biopsies (80%). No evidence of inflammation was found in seven biopsies (17%). Conventional histopathology with haematoxylin-eosin and Masson's trichrome was performed simultaneously, and demonstrated inflammation to be present in 23 of 41 biopsies (56%). An important findings is that CD4+ and CD8+ lymphocytes were absent in 15 of 41 specimens (37%) although there was inflammation proven by the presence of different macrophage phenotypes. The results indicate the necessity of long-term serial investigations of the physiological role of specific inflammatory macrophage phenotypes during the rejection process. It is concluded that the phenotyping of macrophage and endothelial cell differentiation antigens offers a sensitive approach to assess diagnosis of myocardial inflammation as a consequence of ongoing rejection in cardiac allografts.

Phospholipase A2 activation and autoinduction of tumor necrosis factor gene expression by tumor necrosis factor

Tumor necrosis factor (TNF) acts via a cell surface receptor to induce a variety of cellular events including cytolysis, differentiation, and mitogenesis. The mechanisms underlying the cell specific actions of TNF are not known. In the present study, postreceptor events associated with the autoinduction of TNF expression were examined in HL-60 cells. There was no detectable alteration in phospholipase C activity as measured by inositol phosphate generation or release of choline metabolites following TNF stimulation. However, TNF increased the release of arachidonic acid metabolites from HL-60 cells. This increase in arachidonic acid metabolism was associated with a 40% increase in phospholipase A2 activity. Furthermore, the release of arachidonic acid metabolites was blocked by inhibitors of phospholipase A2. Taken together, these findings indicated that TNF stimulates phospholipase A2 and arachidonic acid metabolism in HL-60 cells. The results also demonstrate that TNF expression is induced 15-30 min after stimulation with TNF and that this effect is associated with an increase in the rate of TNF transcription. This autoinduction of TNF mRNA was blocked by inhibitors of phospholipase A2. While the cyclooxygenase inhibitor indomethacin had no detectable effect, ketoconazole and nordihydroguaiaretic acid, inhibitors of lipoxygenase, also blocked the induction of TNF expression by TNF. These findings suggest that phospholipase A2 and lipoxygenase activity are required for the transcriptional activation of TNF gene expression associated with TNF stimulation of HL-60 cells.

Prolonged high dose ARA-C infusions in acute leukemia

High doses of cytosine arabinoside (ara-C) were administered by continuous infusion to 24 patients with acute leukemia in relapse or blast phase of chronic myelogenous leukemia (CML). Ara-C was infused at a dose rate of 250 mg/M2/hr for 36 to 72 hr. The major toxicities were myelosuppression, diarrhea, and abdominal pain. Other toxicities included pulmonary edema, neurotoxicity, and liver function abnormalities. The gastrointestinal toxicity was dose-limiting and a phase II dose was established at 250 mg/M2/hr for 60-72 hr. Four patients treated with this dose schedule had objective responses. Two patients with CML in blast phase returned to chronic phase and have remained stable without maintenance therapy for 12 and 18 months. Two patients with acute myelogenous leukemia in relapse entered complete remissions which continued unmaintained for 4 and 6 months. Steady-state plasma ara-C levels ranged between 7 and 24 x 10(-6) M, while ara-U levels were as high as 4.5 x 10(-4) M. There was no detectable accumulation of ara-C or ara-U during the infusion period. These findings would suggest that the continuous infusion of high dose ara-C may be useful in the treatment of acute leukemia and CML in blast crisis.

Detection of 1-beta-D-arabinofuranosylcytosine incorporation into DNA in vivo

The incorporation of (1-beta-d-arabinofuranosylcytosine (ara-C) into the DNA of leukemic cells is highly correlated with cytotoxicity in vitro. However, the measurement of ara-C incorporation into leukemic cell DNA in vivo during ara-C therapy has been limited by the lack of a suitably sensitive method. A quantitative assay procedure has therefore been developed to determine incorporation of unlabeled ara-C into DNA. This method involves DNA isolation from patient myeloblasts, enzymatic digestion of the DNA, high pressure liquid chromatography separation of the nucleosides, and determination of ara-C in the eluate fractions by radioimmunoassay. Using this approach, incorporation of unlabeled ara-C into DNA of HL-60 cells is log linear over concentrations of 1 to 100 microM ara-C. Furthermore, the extent of ara-C incorporation into DNA as determined by this method correlates significantly with measurements of [3H]ara-C (DNA) formation under similar conditions. This approach has also been applied to clinical samples. Myeloblasts from 6 patients receiving high-dose continuous-infusion ara-C therapy incorporated 0.00-0.36 pmol ara-C/microgram DNA during 24 h of therapy. These findings thus suggest that this method can be used to monitor the in vivo incorporation of ara-C into leukemic cell DNA.

Effects of cis-diamminedichloroplatinum on DNA incorporation and cytotoxicity of 1-beta-D-arabinofuranosylcytosine

1-beta-D-Arabinofuranosylcytosine (ara-C) incorporates into replicating cellular DNA and the extent of this incorporation correlates with loss of clonogenic survival. More recent findings have demonstrated that incorporation of ara-C into DNA undergoing repair of damage induced by u.v. light also results in cell lethality. On the basis of previous studies demonstrating a marked synergism between cis-diamminedichloroplatinum (CDDP) and ara-C in LoVo colon carcinoma cells, the present work has examined the interaction of these agents at a biochemical and cellular level in the MCF-7 human breast carcinoma line. The extent of ara-C incorporation into MCF-7 DNA correlated significantly with loss of clonogenic survival in a dose-dependent manner. The effects of CDDP on the formation of MCF-7 (ara-C)DNA were monitored using both cesium sulfate and cesium chloride density centrifugation. The results demonstrate that CDDP had little, if any, detectable effect on incorporation of ara-C into DNA. Furthermore, combinations of CDDP and low concentrations of ara-C (10(-7) and 10(-6) M) decreased MCF-7 clonogenic survival in an additive but not synergistic manner. Modest synergy was detectable with CDDP and higher ara-C concentrations (10(-5) and 10(-4) M). The interaction between CDDP and ara-C was apparently dependent on concentration, duration of exposure and cell type. There was no dramatic synergy between CDDP and ara-C in MCF-7 cells. These findings may be relevant to the design and interpretation of CDDP/ara-C clinical trials.

Incorporation of 9-beta-D-arabinofuranosyl-2-fluoroadenine into HL-60 cellular RNA and DNA

The incorporation of 9-beta-D-arabinofuranosyl-2-fluoroadenine (F-ara-A) into HL-60 cellular nucleic acids was monitored by cesium sulfate gradient centrifugation. The results demonstrated that F-ara-A incorporated into both RNA and DNA. These findings are in contrast to those previously obtained with 1-beta-D-arabinofuranosylcytosine (ara-C) and 9-beta-arabinofuranosyladenine (ara-A) which demonstrated incorporation of these nucleosides only in DNA. F-ara-A inhibited HL-60 proliferation, and the incorporation of F-ara-A into both DNA and RNA correlated with loss of clonogenic survival. Furthermore, cytostatic concentrations of F-ara-A resulted in the appearance of a more mature phenotype, a finding consistent with the effects of other inhibitors of DNA synthesis. The incorporation of F-ara-A into RNA and DNA should provide new insights regarding the mechanism of action of this agent.

Continuous infusion of high-dose 1-beta-D-arabinofuranosylcytosine: a phase I and pharmacological study

High doses of 1-beta-D-arabinofuranosylcytosine, administered as a continuous i.v. infusion, were evaluated in a Phase I trial in 14 patients with advanced solid tumors. 1-beta-D-Arabinofuranosylcytosine was given at 250 mg/sq m/h for infusions of 12 to 36 h. The mean steady state 1-beta-D-arabinofuranosylcytosine plasma level was 19.6 microM with a range of 9 to 59 microM. The principal toxicity was myelosuppression. An infusion of 18 h was well tolerated by most patients. A Phase II dose of 250 mg/sq m/h for 24 h can be used if platelet support is available. This dose schedule may be useful in the treatment of hematological disorders or in clinical combinations with DNA-damaging agents in the treatment of solid tumors.

Sequential studies on the role of mitoxantrone in the treatment of acute leukemia

Mitoxantrone (Novantrone; 1, 4-dihydroxy-5, 8-bis [[2-[(2-hydroxyethyl) amino]ethyl]amino-] 9, 10 anthracenedione dihydrochloride (NSC 301739] is a synthetic anthracenedione with intercalating properties. Activity has been shown in preclinical studies in mice bearing intraperitoneal P388 and L1210 leukaemias, ADJ-Pc6 plasmacytoma and a variety of solid tumours. In a phase I/II collaborative study fourteen consecutive patients with relapsed or primarily refractory acute leukaemia received a single infusion of mitoxantrone (20-32 mg/m2) at fourteen-day intervals. Antileukaemic activity was seen but there were no complete remissions and toxicity was minimal. Mitoxantrone was subsequently given in a five-day schedule at a dose of 10mg/m2 daily to twenty-one patients with relapsed or refractory acute leukaemia or chronic myeloid leukaemia in blast crisis (CML-BC). Four of five patients in first relapse of acute non-lymphoblastic leukaemia (ANLL) achieved a complete remission (CR). The overall response rate (CR + partial remission (PR] was 48%. In an ongoing phase III study the same (5-day) mitoxantrone treatment has been given in conjunction with a 7-day continuous infusion of cytosine arabinoside (Ara-C) in a kinetically designed schedule based upon the preclinical studies of the Mount Sinai group.

Mitoxantrone in relapsed and refractory acute leukemia

Mitoxantrone is a relatively new synthetic anthracenedione derivative with intercalating properties. An in vitro study with established leukemia cell lines indicated that DNA strand breaks were caused by mitoxantrone; when these were progressive after the initial insult, the cell line was sensitive to the drug. Clinical trials involved patients with relapsed and/or refractory acute leukemia. None of the patients receiving a single slow infusion of mitoxantrone achieved a complete remission. A five day treatment regimen produced an overall response rate of 48% with a complete remission rate of 25%. Toxicity in these preliminary studies was limited compared to that expected with the anthracycline antibiotics. Alopecia and nausea were the only commonly observed side effects. The trials were too short, however, to evaluate possible cardiac toxicity. Mitoxantrone is an acute and relatively nontoxic agent that merits further study to identify its role in the first line therapy of acute leukemia; such studies are underway.

Sequential studies on the role of mitoxantrone in the treatment of acute leukaemia

Mitoxantrone, a synthetic and newly available intercalating agent, was shown to have activity in relapsed or refractory acute leukaemia, which is apparently schedule dependent. A 5-day treatment programme demonstrated impressive activity, with a 50% response rate and 24% complete remissions. Toxicity in these preliminary studies was limited compared to that expected with the anthracycline antibiotics. Mitoxantrone is an active and relatively non-toxic agent which merits further assessment prior to its incorporation in first-line therapy of acute leukaemia.

Thrombocytosis and microthrombocytosis: a clinical evaluation of 372 cases

Data on 372 patients with thrombocytosis (TC), defined as a platelet count over 500 X 10(9)/1, were accumulated in a non-biased fashion. Surgery, per se, was a common cause of TC and malignancy, if uncomplicated by infection, bleeding or surgery, was a less common cause of TC than suggested in previous surveys. The reasons for these apparent differences are discussed. Postoperative TC resolved within 30 days of surgery in the absence of complications. Transient reactive TC due to a variety of causes was accompanied by a significant fall in platelet volume in contrast to the megathrombocytosis found in postsplenectomy and myeloproliferative TC.

Acute renal failure due to gold

A patient with rheumatoid arthritis is described who developed acute renal failure whilst receiving gold. This occurred despite the normal precautions of patient monitoring before each dose was given. The clinical picture suggests this was a hypersensitivity reaction to chrysotherapy.