Effects of Switching to a Heat-Not-Burn Tobacco Product on Biologically Relevant Biomarkers to Assess a Candidate Modified Risk Tobacco Product: A Randomized Trial.

BACKGROUND: Cigarette smoking increases the risk of chronic diseases; heating instead of burning tobacco can lower these risks, contributing to tobacco harm reduction. This study (with 984 adult American smokers) examined whether favorable changes occur in 8 co-primary endpoints (HDL-C, WBC, FEV1%pred, COHb, Total NNAL, sICAM-1, 11-DTX-B2, 8-epi-PGF2α) indicative of biological and functional effects when cigarette smokers switch to the heat-not-burn Tobacco Heating System 2.2 (THS). Additionally, these biomarkers of exposure (BoExp) were quantified: MHBMA, 3-HPMA, Total NNN, CEMA, 3-OH-B[a]P, HMPMA, Total 1-OHP, NEQ, and CO exhaled. METHODS: Participants were randomized to continued smoking of their preferred cigarette brand (n = 496) or to using THS (IQOS brand; n = 488) for 6 months. THS has a maximum heating temperature of 350°C, delivering 1.21 mg nicotine/stick and 3.94 mg glycerin/stick under the Health Canada Intense smoking regimen. RESULTS: The main outcome was a favorable change 6 months after baseline, with statistically significant improvements in 5 of 8 biomarkers of effect (HDL-C, WBC, FEV1%pred, COHb, Total NNAL) when smokers switched to THS compared with those who continued to smoke cigarettes. Likewise, BoExp were markedly reduced. CONCLUSIONS: All endpoints showed favorable changes in the same direction as with smoking cessation and improved biological effects were observed in smokers who predominantly used THS compared with continued cigarette smoking, with similar nicotine levels in both groups. IMPACT: Improvements in 5 of 8 biomarkers of effect are supportive of the research hypothesis, suggestive of disease risk reduction potential for smokers switching to THS instead of continuing to smoke cigarettes.

Biological and Functional Changes in Healthy Adult Smokers Who Are Continuously Abstinent From Smoking for One Year: Protocol for a Prospective, Observational, Multicenter Cohort Study.

BACKGROUND: The harm of smoking results mainly from long-term exposure to harmful and potentially harmful constituents (HPHCs) generated by tobacco combustion. Smoking cessation (SC) engenders favorable changes of clinical signs, pathomechanisms, and metabolic processes that together could reduce the harm of smoking-related diseases to a relative risk level approximating that of never-smokers over time. In most SC studies, the main focus is on the quitting rate of the SC program being tested. As there is limited information in the literature on short to multiple long-term functional or biological changes following SC, more data on short to mid-term favorable impacts of SC are needed. OBJECTIVE: The overall aim of the study was to assess the reversibility of the harm related to smoking over 1 year of continuous smoking abstinence (SA). This has been verified by assessing a set of biomarkers of exposure to HPHCs and a set of biomarkers of effect indicative of multiple pathophysiological pathways underlying the development of smoking-related diseases. METHODS: This multiregional (United States, Japan, and Europe), multicenter (42 sites) cohort study consisting of a 1-year SA period in an ambulatory setting was conducted from May 2015 to May 2017. A total of 1184 male and female adult healthy smokers, willing to quit smoking, were enrolled in the study. Nicotine replacement therapy (NRT) was provided for up to 3 months upon the subject's request. SC counseling and behavioral support were continuously provided. Biomarkers of exposure to HPHCs and biomarkers of effect were assessed in urine and blood at baseline, Month 3, Month 6, and Month 12. Cardiovascular biomarkers of effect included parameters reflecting inflammation (white blood cell), lipid metabolism (high-density lipoprotein cholesterol), endothelial function (soluble intercellular adhesion molecule-1), platelet function (11-dehydrothromboxane B2), oxidative stress (8-epi-prostaglandin F2 alpha), and carbon monoxide exposure (carboxyhemoglobin). Respiratory biomarkers of effect included lung function parameters and cough symptoms. The biomarkers of effect to evaluate genotoxicity (total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) and xenobiotic metabolism (cytochrome P450 2A6 activity) were also assessed. Continuous SA was verified at each visit following the actual quit date using self-reporting and chemical verification. Safety assessments included adverse events and serious adverse events, body weight, vital signs, spirometry, electrocardiogram, clinical chemistry, hematology and urine analysis safety panel, physical examination, and concomitant medications. RESULTS: In total, 1184 subjects (50.1% male) were enrolled; 30% of them quit smoking successfully for 1 year. Data analyses of the study results are ongoing and will be published after study completion. CONCLUSIONS: This study provides insights into biological and functional changes and health effects, after continuous SA over 1 year. Study results will be instrumental in assessing novel alternative products to cigarettes considered for tobacco harm reduction strategies. TRIAL REGISTRATION: ClinicalTrials.gov NCT02432729; http://clinicaltrials.gov/ct2/show/NCT02432729 (Archived by WebCite at http://www.webcitation.org/78QxovZrr). INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/12138.

Evaluation of Biological and Functional Changes in Healthy Smokers Switching to the Tobacco Heating System 2.2 Versus Continued Tobacco Smoking: Protocol for a Randomized, Controlled, Multicenter Study.

BACKGROUND: Tobacco harm reduction, substituting less harmful tobacco products for combustible cigarettes, is a complementary approach for smokers who would otherwise continue to smoke. The Philip Morris International (PMI) Tobacco Heating System (THS) 2.2 is a novel tobacco product with the potential to reduce the risk of harm in smokers compared to continued smoking of combustible cigarettes. It heats tobacco electrically in a controlled manner, never allowing the temperature to exceed 350°C, thereby preventing the combustion process from taking place and producing substantially lower levels of toxicants while providing nicotine, taste, ritual, and a sensory experience that closely parallels combustible cigarettes. Previous clinical studies have demonstrated reduced exposure to the toxicants (approaching the levels observed after quitting) for smokers who switched to THS 2.2, for three months. For adult smokers who would otherwise continue smoking combustible cigarettes, switching to THS 2.2 may represent an alternative way to reduce the risk of tobacco-related diseases. OBJECTIVE: This study aimed to further substantiate the harm reduction potential of THS 2.2 by demonstrating favorable changes in a set of 8 coprimary endpoints, representative of pathomechanistic pathways (ie, inflammation, oxidative stress, lipid metabolism, respiratory function, and genotoxicity), linked to smoking-related diseases, in smokers switching from combustible cigarettes to THS 2.2. METHODS: This study was a randomized, controlled, two-arm parallel group, multicenter ambulatory US study conducted in healthy adult smokers switching from combustible cigarettes to THS 2.2 compared with smokers continuing to smoke combustible cigarettes for six months. Subjects had a smoking history of at least ten years and did not intend to quit within the next six months. RESULTS: Enrollment started in March 2015 and the trial was completed in September 2016. In total, 984 subjects were randomized (combustible cigarettes, n=483; THS 2.2, n=477), and 803 completed the study. The results are expected to be available in a subsequent publication in 2019. CONCLUSIONS: In this paper, we describe the rationale and design for this clinical study that focused on the evaluation of THS 2.2's potential to reduce the risk of smoking-related diseases compared with that of combustible cigarettes. This study will provide insights regarding favorable changes in biological and functional endpoints informed by effects known to be seen upon smoking cessation. TRIAL REGISTRATION: ClinicalTrials.gov NCT02396381; http://clinicaltrials.gov/ct2/show/NCT02396381 (Archived by WebCite at http://www.webcitation.org/71PCRdagP). REGISTERED REPORT IDENTIFIER: RR1-10.2196/11294.

Effects of Switching to the Tobacco Heating System 2.2 Menthol, Smoking Abstinence, or Continued Cigarette Smoking on Biomarkers of Exposure: A Randomized, Controlled, Open-Label, Multicenter Study in Sequential Confinement and Ambulatory Settings (Part 1).

Introduction: The menthol Tobacco Heating System 2.2 (mTHS) is a newly developed candidate modified-risk tobacco product intended to reduce exposure to the harmful and potentially harmful constituents (HPHCs) of conventional cigarette (CC) smoke. This study examined the impact of switching to mTHS on biomarkers of exposure to HPHCs relative to menthol CCs (mCCs) and smoking abstinence (SA). Methods: In this three-arm, parallel-group study, 160 Japanese adult smokers (23-65 years; smoking ≥10 mCCs per day) were randomized to mTHS (n = 78), mCC (n = 42), or SA (n = 40) for 5 days in confinement and 85 days in ambulatory settings. Endpoints included biomarkers of exposure to HPHCs, human puffing topography, safety, and subjective effects of smoking measures. Results: After 5 days of product use, the concentrations of carboxyhemoglobin, 3-hydroxypropylmercapturic acid, monohydroxybutenyl mercapturic acid, and S-phenylmercapturic acid were 55%, 49%, 87%, and 89% lower (p < .001), respectively, in the mTHS group than in the mCC group. Other biomarkers of exposure (measured as secondary endpoints) were 50%-94% lower in the mTHS group than in the mCC group on day 5. These reductions in the mTHS group were maintained at day 90, similar to the SA group. Switching to mTHS was associated with changes in human puffing topography (shorter puff intervals and more frequent puffs). The urge-to-smoke and smoking satisfaction levels on day 90 were similar in the mTHS and the mCC groups. Conclusion: Switching from mCCs to mTHS significantly reduced exposure to HPHCs relative to continuing smoking mCCs with concentrations similar to those observed following SA in Japanese adult smokers. Implications: This randomized study compared the impact of switching to a modified-risk tobacco product candidate mTHS on biomarkers of exposure to HPHCs of cigarette smoke relative to continuing smoking cigarettes or abstaining from smoking in sequential confinement and ambulatory settings. The study showed that switching to mTHS was associated with significant biomarker reductions within 5 days in confinement, these reductions being maintained throughout the ambulatory setting up to day 90. The results provide evidence that switching to mTHS reduces real-life exposure to HPHCs in adult smokers.

Effects of Switching to the Menthol Tobacco Heating System 2.2, Smoking Abstinence, or Continued Cigarette Smoking on Clinically Relevant Risk Markers: A Randomized, Controlled, Open-Label, Multicenter Study in Sequential Confinement and Ambulatory Settings (Part 2).

Introduction: Modified-risk tobacco products are expected to reduce exposure to harmful and potentially harmful constituents of cigarette smoke, and ultimately reduce the health burden of smoking-related diseases. Clinically relevant risk markers of smoking-related diseases inform about the risk profile of new tobacco products in the absence of in-market epidemiological data. The menthol Tobacco Heating System 2.2 (mTHS) is a modified-risk tobacco product in development as an alternative to cigarettes (conventional cigarettes [CCs]). Methods: In this parallel-group study, Japanese adult smokers (23-65 years; ≥10 mCCs/day) were randomized to mTHS, menthol CCs (mCC), or smoking abstinence (SA) for 5 days in confinement and 85 days in ambulatory settings. Endpoints included biomarkers of exposure to harmful and potentially harmful constituents and clinically relevant risk markers of smoking-related diseases. Results: One-hundred and sixty participants were randomized to the mTHS (n = 78), mCC (n = 42), and SA (n = 40) groups. Switching to the mTHS was associated with reductions in biomarkers of exposure compared with continuing mCCs. Reductions in 8-epi-prostaglandin F2α (biomarker of oxidative stress), 11-dehydro-thromboxane B2 (biomarker of platelet activation), soluble intracellular adhesion molecule-1 (biomarker of endothelial function), and an increase in high-density lipoprotein cholesterol (biomarker of lipid metabolism) and forced expiratory volume in 1 second (biomarker of lung function) occurred in the mTHS group compared with the mCC group. The changes in the mTHS group approached those in the SA group. Conclusions: Switching from mCCs to mTHS was associated with improvements in clinically relevant risk markers linked to mechanistic pathways involved in smoking-related diseases. Implications: In this three-way randomized study, switching from menthol cigarettes to mTHS for 5 days in confinement and 85 days in ambulatory settings was associated with reductions in biomarkers of exposure to cigarette smoke, and changes were observed in clinically relevant biomarkers of oxidative stress (8-epi-prostaglandin F2α), platelet activity (11-dehydro-thromboxane B2), endothelial function (soluble intracellular adhesion molecule-1), lipid metabolism (high-density lipoprotein cholesterol) and lung function (forced expiratory volume in 1 second), similar to the SA group. The results suggest that switching to the mTHS has the potential to reduce the adverse health effects of conventional cigarettes.

Nicotine pharmacokinetic profiles of the Tobacco Heating System 2.2, cigarettes and nicotine gum in Japanese smokers.

Two open-label randomized cross-over studies in Japanese smokers investigated the single-use nicotine pharmacokinetic profile of the Tobacco Heating System (THS) 2.2, cigarettes (CC) and nicotine replacement therapy (Gum). In each study, one on the regular and one on the menthol variants of the THS and CC, both using Gum as reference, 62 subjects were randomized to four sequences: Sequence 1: THS - CC (n = 22); Sequence 2: CC - THS (n = 22); Sequence 3: THS - Gum (n = 9); Sequence 4: Gum - THS (n = 9). Plasma nicotine concentrations were measured in 16 blood samples collected over 24 h after single use. Maximal nicotine concentration (Cmax) and area under the curve from start of product use to time of last quantifiable concentration (AUC0-last) were similar between THS and CC in both studies, with ratios varying from 88 to 104% for Cmax and from 96 to 98% for AUC0-last. Urge-to-smoke total scores were comparable between THS and CC. The THS nicotine pharmacokinetic profile was close to CC, with similar levels of urge-to-smoke. This suggests that THS can satisfy smokers and be a viable alternative to cigarettes for adult smokers who want to continue using tobacco.

Nicotine Population Pharmacokinetics in Healthy Adult Smokers: A Retrospective Analysis.

BACKGROUND AND OBJECTIVE: Characterizing nicotine pharmacokinetics is challenging in the presence of background exposure. We performed a combined retrospective population pharmacokinetic analysis of 8 trials, including exposure to Tobacco Heating System and cigarettes (both inhaled), nicotine nasal spray and oral nicotine gum. METHOD: Data from 4 single product use trials were used to develop a population pharmacokinetic model with Phoenix® NLME™ and to derive exposure parameters. Data from 4 separate ad libitum use studies were used for external validation. A total of 702 healthy adult smokers (54% males; 21-66 years of age; smoking ≥10 cigarettes/day; from US, Europe and Japan) were eligible for participation. RESULTS: Two-compartment linear disposition combined with zero-order absorption model was adequate to describe nicotine pharmacokinetics, and a mono-exponentially decreasing background component was utilized to account for nicotine carry-over effects. Apparent nicotine clearance was typically 0.407 L/min in males and 26% higher in females (68% inter-individual variability). Bioavailability was product-specific, decreased with increasing nicotine ISO yield, and increased with increasing body weight. Absorption duration was apparently prolonged with nicotine gum. The typical initial and terminal half-lives were 1.35 and 17 h, respectively. The presence of menthol did not impact the determinants of the area under the curve. The model adequately described the external validation data. CONCLUSIONS: The population model was able to describe in different populations the nicotine pharmacokinetics after single product use and after 4 days of ad libitum use of Tobacco Heating System, cigarettes, and of different nicotine replacement therapies with various routes of administration.

Comparison of the Pharmacokinetics of Nicotine Following Single and Ad Libitum Use of a Tobacco Heating System or Combustible Cigarettes.

INTRODUCTION: We aimed to compare the pharmacokinetics of nicotine between the heat-not-burn Tobacco Heating System 2.1 (THS 2.1) and combustible cigarettes (CCs). We also examined whether the subjective urge to smoke was associated with the pharmacokinetics of nicotine. METHODS: This open-label, randomized, two-period, two-sequence crossover study conducted in 28 healthy smokers assessed the pharmacokinetics of nicotine after single and ad libitum use of the THS 2.1 or CCs. During the 7-day confinement period, blood samples were drawn for pharmacokinetic analysis. Subjective effects related to THS 2.1 or CC use were assessed using the Questionnaire of Smoking Urges (QSU-Brief). RESULTS: The nicotine delivery rate was similar with the THS 2.1 and CCs after single and ad libitum use. The time to the maximum nicotine concentration was 8 minutes after single use of the THS 2.1 and CCs. The time to the peak concentration following ad libitum use was similar between the THS 2.1 and CCs. The maximum plasma nicotine concentration after single use of the THS 2.1 was 8.4 ng/mL, 70.3% of that obtained with CCs. A transient reduction from baseline in the urge to smoke of 40% was observed 15 minutes after the single use of both the THS 2.1 and CCs. The mean QSU-Brief total scores following single and ad libitum use were similar for the THS 2.1 and CCs. CONCLUSIONS: These results suggest that the THS 2.1 effectively delivers nicotine and achieves similar pharmacokinetic profiles to CCs. The THS 2.1 also reduced the urge to smoke similarly to CCs. IMPLICATIONS: Reducing exposure to toxicants and safer delivery of nicotine are among the strategies that may reduce the harm of smoking-related diseases. In the present study, we investigated the pharmacokinetics of nicotine and their effects on the urge to smoke using the THS 2.1. It was developed to replicate the ritual of smoking as closely as possible by providing nicotine in a way that mimics CC smoking, but limits pyrolysis and combustion by heating tobacco at a much lower temperature than CCs (heat-not-burn).

Survival after locoregional treatments for hepatocellular carcinoma: a cohort study in real-world patients.

Evidence of relative effectiveness of local treatments for hepatocellular carcinoma (HCC) is scanty. We investigated, in a retrospective cohort study, whether surgical resection, radiofrequency ablation (RFA), percutaneous ethanol injection (PEI), and transarterial embolization with (TACE) or without (TAE) chemotherapy resulted in different survival in clinical practice. All patients first diagnosed with HCC and treated with any locoregional therapy from 1998 to 2002 in twelve Italian hospitals were eligible. Overall survival (OS) was the unique endpoint. Three main comparisons were planned: RFA versus PEI, surgical resection versus RFA/PEI (combined), TACE/TAE versus RFA/PEI (combined). Propensity score method was used to minimize bias related to non random treatment assignment. Overall 425 subjects were analyzed, with 385 (91%) deaths after a median followup of 7.7 years. OS did not significantly differ between RFA and PEI (HR 1.11, 95% CI 0.79-1.57), between surgery and RFA/PEI (HR 0.95, 95% CI 0.64-1.41) and between TACE/TAE and RFA/PEI (HR 0.88, 95% CI 0.66-1.17). 5-year OS probabilities were 0.14 for RFA, 0.18 for PEI, 0.27 for surgery, and 0.15 for TACE/TAE. No locoregional treatment for HCC was found to be more effective than the comparator. Adequately powered randomized clinical trials are still needed to definitely assess relative effectiveness of locoregional HCC treatment.

Transverse maxillary arch form and mandibular asymmetry in patients with posterior unilateral crossbite.

INTRODUCTION: Posterior unilateral crossbite treatment is usually oriented to the maxilla. The aims of this retrospective investigation were (1) to study the maxillary arch morphology in patients with posterior unilateral crossbite and (2) to evaluate the possible association between the transverse maxillary arch morphology and the skeletal symmetry or asymmetry of the corresponding mandible. METHODS: Data from maxillary arch occlusograms and posteroanterior and panoramic radiograph tracings of the mandible were obtained for 94 patients with posterior unilateral crossbite and midline deviation. A multiple linear regression model was used to assess the association of transverse maxillary arch morphology with demographic and clinical characteristics. The prevalence of skeletal asymmetry was modeled by using a multiple logistic regression on transverse maxillary arch morphology, adjusted for the patients' characteristics. RESULTS: Three maxillary arch morphologies were found at the crossbite side: symmetric, contracted, and expanded. The expanded crossbite sides were statistically associated with mandibular asymmetry. CONCLUSIONS: Different transverse maxillary arch forms at the crossbite side were observed in our patients with posterior unilateral crossbite. This finding might be interpreted as a diagnostic and prognostic key for mandibular asymmetry, paving the way for new treatment directions.

Clinical assessment of patients with advanced non-small-cell lung cancer eligible for second-line chemotherapy: a prognostic score from individual data of nine randomised trials.

PURPOSE: Knowledge of prognostic factors for advanced non-small-cell lung cancer (NSCLC) patients eligible for second-line treatment is scarce. The aim of this study was to assess the prognostic role of a number of routinely collected clinical variables and to provide a summary index to discriminate patients according to probability of survival. METHODS: Individual data from nine randomised trials of second-line treatment in advanced NSCLC were analysed. Primary end-point was overall survival (OS). Cox model, stratified by trial, was used for multivariate analyses, and a prognostic index was provided and validated according to an internal/external procedure. RESULTS: Out of 1239 patients, 1197 patients (97%) had complete information. Median OS was 7.4months. At multivariate analysis, prognosis was significantly influenced by gender (worse in males), performance status (PS), tumour histology (worse in squamous and other histology versus adenocarcinoma), stage (worse in IV versus IIIB), type of previous treatment (worse for patients pretreated with platinum) and response to first-line (worse for patients not obtaining objective response). Prognostic score values range from 0 to 14. When three categories were derived, median overall survival values were equal to 11.6, 7.5 and 3.0months for best (<5), intermediate (5-9) and worst (>9) categories, respectively. CONCLUSION: Prognosis of patients eligible for second-line treatment of advanced NSCLC is significantly conditioned by gender, PS, histology, stage, previous use of platinum and response to first-line. A prognostic score was derived that discriminates well subjects with a relatively more favourable prognosis and those with very short life expectancy.

Anti-cyclic citrullinated peptide antibodies in primary Sjögren syndrome may be associated with non-erosive synovitis.

INTRODUCTION: The purpose of this study was to investigate the prevalence of cyclic citrullinated peptide antibodies (anti-CCP) in patients with primary Sjögren syndrome (pSS) and its correlation with clinical and laboratory data. METHODS: We analysed the clinical and serological data of 155 consecutive patients with pSS. Among these, 14 were excluded due to fulfillment of American College of Rheumatology criteria for rheumatoid arthritis (RA). So, 141 patients (27 males and 114 females; mean age 48 years, range 39 to 60) were clinically assessed for the presence of synovitis (objective swelling of one or more joints) and extra-glandular involvement. The anti-CCP antibodies were tested using a commercially available second-generation enzyme-linked immunosorbent assay. IgM rheumatoid factor (RF) was determined by nephelometry. RESULTS: Fourteen patients (9.9%) had moderate to high levels of anti-CCP, and 94 (66.7%) were positive for RF. Eighty-one (57.4%) showed extra-glandular involvement, and 44 (31.2%) had synovitis without any radiographic sign of erosion. There was a close correlation between the presence of anti-CCP and synovitis (P < 0.001) but no association between anti-CCP and extra-glandular involvement (P = 0.77). Multivariate analysis confirmed the association between anti-CCP and an increased prevalence of synovitis (prevalence odds ratio for positive versus negative anti-CCP status 7.611, 95% confidence interval 1.475 to 74.870; P = 0.010). CONCLUSION: Only a minority of patients with pSS are anti-CCP-positive, which seems to be closely associated with the prevalence of synovitis. Anti-CCP positivity in patients with pSS therefore may be a predictor of future progress to RA or an expression of the inflammatory process of synovial tissue.

Anti-polymer antibodies are correlated with pain and fatigue severity in patients with fibromyalgia syndrome.

OBJECTIVE: To investigate the prevalence of antipolymer antibody (APA) in patients with fibromyalgia (FM) and to examine its association with FM severity symptoms. METHODS: The study population consisted of 79 FM patients and 75 controls: 32 with psoriatic arthritis and 43 with rheumatoid arthritis APA levels were indirectly assayed using a commercial ELISA kit from Corgenix (Westmister, Colorado, USA). Optical density (OD) values were recorded on duplicates of each of the reference and patient samples. Among clinical variables we investigated pain, measured according to visual analog scales (VAS: 0-100), fatigue, stiffness, anxiety, depression, all measured by VAS (0-100), and health status measured by Fibromyalgia Impact Questionnaire (FIQ). RESULTS: Sixteen of the 79 FM patients (20.3%) and 12/78 controls (15.4%) were positive for APAs (P = 0.536). Following ROC analysis, area under curve (AUC) was 0.49 (95% CI: 0.40, 0.58). Focusing on FM patients, we observed a correlation between APA titre and pain (tau: - 0.221; P = 0.020) and fatigue (tau: - 0.205; P = 0.032) at univariate analysis. Binomial regression analysis, controlling for clinical and demographic variables, showed that pain (PPR: 0.923; P = 0.007) and fatigue (PPR: 0.948; P = 0.024) were significantly associated with APA test sensitivity. CONCLUSIONS: APA test exhibited a low sensitivity in FM patients and it did not distinguish this group of patients from the controls enrolled in this study. Interestingly, positive APA test prevalence increased with less severe pain or fatigue.

Vbmp: variational Bayesian Multinomial Probit Regression for multi-class classification in R.

SUMMARY: Vbmp is an R package for Gaussian Process classification of data over multiple classes. It features multinomial probit regression with Gaussian Process priors and estimates class posterior probabilities employing fast variational approximations to the full posterior. This software also incorporates feature weighting by means of Automatic Relevance Determination. Being equipped with only one main function and reasonable default values for optional parameters, vbmp combines flexibility with ease of usage as is demonstrated on a breast cancer microarray study. AVAILABILITY: The R library vbmp implementing this method is part of Bioconductor and can be downloaded from http://www.dcs.gla.ac.uk/~girolami