Real-life effectiveness of carfilzomib in patients with relapsed multiple myeloma receiving treatment in the context of early access: The CARMYN study

The real-life retrospective observational study CARMYN aimed at investigating the long-term efficacy and safety of carfilzomib in combination with dexamethasone and lenalidomide (KRd, 159 patients). These patients (62% in first and 38% in second relapse, median age 62 yo) were treated between 02/2014 and 02/2017. Most had been pre-exposed to bortezomib (98.2%) and to an IMID (75.4%). At the time of collection, 90% had permanently discontinued carfilzomib. Data collection was conducted from January to July 2021 in 27 participating sites, after a median of 39 months follow-up. For patients treated with KRd, an overall response rate of 78.4% translated in a median progression free survival (PFS) of 24.0 months (95% CI 18.8-27.6) and a median overall survival (OS) of 51.1 months (95% CI 41.3-not reached). Results were poorer but difficult to interpret in the small cohort of Kd recipients. The study is one of the longest real-life studies of carfilzomib treatment in patients in first or second relapse. CARMYN confirmed the real-life long-term efficacy of carfilzomib in combination with lenalidomide and dexamethasone with results similar to those of clinical trials. The KRd regimen is thus an option to consider for late relapses in the current context of MM management.

Effect of Romosozumab Treatment in Postmenopausal Women With Osteoporosis and Knee Osteoarthritis: Results From a Substudy of a Phase 3 Clinical Trial

OBJECTIVE

Romosozumab is a bone-forming agent approved for osteoporosis treatment. Here we report results of the protocol-specified, noninferiority osteoarthritis substudy of the fracture study in postmenopausal women with osteoporosis (FRAME), which evaluated the effect of romosozumab versus placebo on knee osteoarthritis in patients with a clinical history of osteoarthritis.

METHODS

Women in FRAME with a history of knee osteoarthritis were eligible for enrollment in the osteoarthritis substudy; key inclusion criteria were osteoarthritis-related signal knee pain, morning stiffness lasting less than 30 minutes, knee crepitus, and knee osteoarthritis confirmed by x-ray within 12 months. The protocol-specified outcomes were change from baseline through month 12 in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, incidence of worsening knee osteoarthritis, and treatment-emergent adverse events (TEAEs) with romosozumab versus placebo. In a post hoc analysis, percentage change from baseline to month 12 in bone mineral density (BMD) was assessed.

RESULTS

Of 7180 women in FRAME, 347 participated in the osteoarthritis substudy (placebo, 177; romosozumab, 170). At month 12, no significant difference in progression of knee osteoarthritis was observed with romosozumab versus placebo (least squares mean total WOMAC score: -2.2 vs. -1.3; P = 0.71). Incidence of worsening symptoms of knee osteoarthritis was comparable between romosozumab (17.1%) and placebo (20.5%) (odds ratio 0.9 [95% confidence interval: 0.5, 1.7]; P = 0.69). Incidence of TEAEs of osteoarthritis was numerically lower with romosozumab (13 [7.7%]) versus placebo (21 [12.0%]). BMD gains were higher with romosozumab.

CONCLUSION

Romosozumab treatment did not impact knee pain or function in postmenopausal women with osteoporosis and knee osteoarthritis and resulted in significant BMD gains in these women.

Zero-shot mutation effect prediction on protein stability and function using RoseTTAFold

Predicting the effects of mutations on protein function and stability is an outstanding challenge. Here, we assess the performance of a variant of RoseTTAFold jointly trained for sequence and structure recovery, RFjoint , for mutation effect prediction. Without any further training, we achieve comparable accuracy in predicting mutation effects for a diverse set of protein families using RFjoint to both another zero-shot model (MSA Transformer) and a model that requires specific training on a particular protein family for mutation effect prediction (DeepSequence). Thus, although the architecture of RFjoint was developed to address the protein design problem of scaffolding functional motifs, RFjoint acquired an understanding of the mutational landscapes of proteins during model training that is equivalent to that of recently developed large protein language models. The ability to simultaneously reason over protein structure and sequence could enable even more precise mutation effect predictions following supervised training on the task. These results suggest that RFjoint has a quite broad understanding of protein sequence-structure landscapes, and can be viewed as a joint model for protein sequence and structure which could be broadly useful for protein modeling.

Attenuated IL-2 muteins leverage the TCR signal to enhance regulatory T cell homeostasis and response in vivo

Interleukin-2 (IL-2), along with T-cell receptor (TCR) signaling, are required to control regulatory T cell (Treg) homeostasis and function in vivo. Due to the heightened sensitivity to IL-2, Tregs retain the ability to respond to low-dose or attenuated forms of IL-2, as currently being developed for clinical use to treat inflammatory diseases. While attenuated IL-2 increases Treg selectivity, the question remains as to whether a weakened IL-2 signal sufficiently enhances Treg suppressive function(s) toward disease modification. To understand this question, we characterized the in vivo activity and transcriptomic profiles of two different attenuated IL-2 muteins in comparison with wildtype (WT) IL-2. Our study showed that, in addition to favoring Tregs, the attenuated muteins induced disproportionately robust effects on Treg activation and conversion to effector Treg (eTreg) phenotype. Our data furthermore suggested that Tregs activated by attenuated IL-2 muteins showed reduced dependence on TCR signal, at least in part due to the enhanced ability of IL-2 muteins to amplify the TCR signal in vivo. These results point to a new paradigm wherein IL-2 influences Tregs' sensitivity to antigenic signal, and that the combination effect may be leveraged for therapeutic use of attenuated IL-2 muteins.

A three-dimensional method for morphological analysis and flow velocity estimation in microvasculature on-a-chip

Three-dimensional (3D) imaging techniques (e.g., confocal microscopy) are commonly used to visualize in vitro models, especially microvasculature on-a-chip. Conversely, 3D analysis is not the standard method to extract quantitative information from those models. We developed the μVES algorithm to analyze vascularized in vitro models leveraging 3D data. It computes morphological parameters (geometry, diameter, length, tortuosity, eccentricity) and intravascular flow velocity. μVES application to microfluidic vascularized in vitro models shows that they successfully replicate functional features of the microvasculature in vivo in terms of intravascular fluid flow velocity. However, wall shear stress is lower compared to in vivo references. The morphological analysis also highlights the model's physiological similarities (vessel length and tortuosity) and shortcomings (vessel radius and surface-over-volume ratio). The addition of the third dimension in our analysis produced significant differences in the metrics assessed compared to 2D estimations. It enabled the computation of new indices, such as vessel eccentricity. These μVES capabilities can find application in analyses of different in vitro vascular models, as well as in vivo and ex vivo microvasculature.

Opportunistic CT Screening-Machine Learning Algorithm Identifies Majority of Vertebral Compression Fractures: A Cohort Study

Vertebral compression fractures (VCF) are common in patients older than 50 years but are often undiagnosed. Zebra Medical Imaging developed a VCF detection algorithm, with machine learning, to detect VCFs from CT images of the chest and/or abdomen/pelvis. In this study, we evaluated the diagnostic performance of the algorithm in identifying VCF. We conducted a blinded validation study to estimate the operating characteristics of the algorithm in identifying VCFs using previously completed CT scans from 1200 women and men aged 50 years and older at a tertiary-care center. Each scan was independently evaluated by two of three neuroradiologists to identify and grade VCF. Disagreements were resolved by a senior neuroradiologist. The algorithm evaluated the CT scans in a separate workstream. The VCF algorithm was not able to evaluate CT scans for 113 participants. Of the remaining 1087 study participants, 588 (54%) were women. Median age was 73 years (range 51-102 years; interquartile range 66-81). For the 1087 algorithm-evaluated participants, the sensitivity and specificity of the VCF algorithm in diagnosing any VCF were 0.66 (95% confidence interval [CI] 0.59-0.72) and 0.90 (95% CI 0.88-0.92), respectively, and for diagnosing moderate/severe VCF were 0.78 (95% CI 0.70-0.85) and 0.87 (95% CI 0.85-0.89), respectively. Implementing this VCF algorithm within radiology systems may help to identify patients at increased fracture risk and could support the diagnosis of osteoporosis and facilitate appropriate therapy. © 2023 Amgen, Inc. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Real-World Evidence Assessing Psoriatic Arthritis by Disease Domain: An Evaluation of the CorEvitas Psoriatic Arthritis/Spondyloarthritis Registry

OBJECTIVE

Real-world studies assessing treatment response by psoriatic arthritis (PsA) domains are limited. This study aimed to describe the patient characteristics, frequency and combinations of disease domains, disease activity, and patient-reported outcomes (PROs) by PsA domains in patients who initiated treatment with a tumor necrosis factor inhibitor (TNFi) or interleukin-17 inhibitor (IL-17i).

METHODS

Adults with PsA who initiated treatment with a TNFi or an IL-17i between January 2013 and January 2021 and had a 6 (±3)-month follow-up were included. The prevalence of PsA domains, the most common domain combinations, treatment persistence, and unadjusted change in disease activity and PROs from baseline to 6 months for each PsA domain were summarized descriptively.

RESULTS

Of the 1005 eligible patients, 63% were receiving TNFi and 37% were receiving IL-17i. Forty percent of TNFi and 14% of IL-17i initiators received these treatments as first-line therapy. Peripheral arthritis and skin disease were the most common PsA domains identified in 86% and 82% of patients, respectively, and the triad of peripheral arthritis, skin disease, and nail psoriasis was the most common domain combination observed in 14% of patients. More than two thirds (68%) of patients remained on therapy at 6 months' follow-up. Improvements in disease activity and PROs were observed across all PsA domains in those receiving TNFi or IL-17i.

CONCLUSION

This real-world analysis highlights the heterogeneity in domain presentation; therefore, assessing all PsA domains is important for optimal disease management. Improvements in outcomes across all PsA domains demonstrate the effectiveness of TNFi and IL-17i in diverse patient groups exhibiting different phenotypes of PsA.

Activity of TNT: a phase 2 study using talimogene laherparepvec, nivolumab and trabectedin for previously treated patients with advanced sarcomas (NCT# 03886311)

Background

Intratumoral injection of talimogene laherparepvec evokes a cytotoxic immune response. Therefore, the combination of talimogene laherparepvec with trabectedin and nivolumab may have synergistic effects in advanced sarcomas.

Patients and methods

This phase 2 trial was conducted from May 30, 2019 to January 31, 2022. Endpoints: Primary: Progression free survival rate at month 12. Secondary: Best overall response, progression free survival rate at 6 and 9 months, overall survival rate at 6, 9, and 12 months, incidence of conversion of an unresectable tumor to a resectable tumor, and incidence of adverse events. Eligible patients had to be ≥ 18 years of age, have advanced histologically proven sarcoma, at least 1 previous chemotherapy regimen, and at least one accessible tumor for intratumoral injection. Treatment: Trabectedin intravenously (1.2 mg/m² q3 weeks), nivolumab intravenously (3 mg/kg q2 weeks), and intratumoral talimogene laherparepvec (1x10⁸ plaque forming units/ml q2 weeks).

Results

Median time of follow-up: 15.2 months. Efficacy analysis: Thirty-nine patients who had completed at least one treatment cycle and had a follow-up computerized tomography were evaluable for efficacy analysis. Median number of prior therapies: 4 (range 1-11). Progression free survival rate at month 12, 36.7%. Confirmed Best Overall Response by Response Evaluation Criteria in Solid Tumors v1.1 = 3 partial responses, 30 stable disease, 6 progressive disease. Best Overall Response Rate, 7.7%, Disease Control Rate, 84.6%; median progression free survival, 7.8 (95% Confidence Intervals: 4.1-13.1) months; 6-, 9-, 12-month progression free survival rates, 54.5%/45.9%/36.7%; median overall survival 19.3 (95% Confidence Intervals: 12.8 -.) months; 6-, 9- and 12-month overall survival rate, 86.9%/73.3%/73.3%. One patient had a complete surgical resection. Fifty percent of patients had a ≥ grade 3 treatment related adverse events which included anemia (6%), thrombocytopenia (6%), neutropenia (4%), increased alanine transaminase (4%), decreased left ventricular ejection fraction (4%), dehydration (4%), hyponatremia (4%).

Conclusions

Taken together these data suggest that the TNT regimen is effective and safe for advanced previously treated sarcomas, and is worth being further studied in a randomized phase 3 trial as first- or second- line treatment for patients with advanced sarcomas.

Denosumab Treatment Does Not Halt Progression of Bone Lesions in Multicentric Carpotarsal Osteolysis Syndrome

Here we report the use of denosumab, a monoclonal antibody against receptor activator of nuclear factor κB ligand (RANKL), as monotherapy for multicentric carpotarsal osteolysis syndrome (MCTO) in an 11.5-year-old male with a heterozygous missense mutation in MAFB (c.206C>T; p.Ser69Leu). We treated the subject with 0.5 mg/kg denosumab every 60-90 days for 47 months and monitored bone and mineral metabolism, kidney function, joint range of motion (ROM), and bone and joint morphology. Serum markers of bone turnover reduced rapidly, bone density increased, and renal function remained normal. Nevertheless, MCTO-related osteolysis and joint immobility progressed during denosumab treatment. Symptomatic hypercalcemia and protracted hypercalciuria occurred during weaning and after discontinuation of denosumab and required treatment with zoledronate. When expressed in vitro, the c.206C>T; p.Ser69Leu variant had increased protein stability and produced greater transactivation of a luciferase reporter under the control of the PTH gene promoter than did wild-type MafB. Based on our experience and that of others, denosumab does not appear to be efficacious for MCTO and carries a high risk of rebound hypercalcemia and/or hypercalciuria after drug discontinuation. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Is local review of positron emission tomography scans sufficient in diffuse large B-cell lymphoma clinical trials? A CALGB 50303 analysis

BACKGROUND

Quantitative methods of Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) interpretation, including the percent change in FDG uptake from baseline (ΔSUV), are under investigation in lymphoma to overcome challenges associated with visual scoring systems (VSS) such as the Deauville 5-point scale (5-PS).

METHODS

In CALGB 50303, patients with DLBCL received frontline R-CHOP or DA-EPOCH-R, and although there were no significant associations between interim PET responses assessed centrally after cycle 2 (iPET) using 5-PS with progression-free survival (PFS) or overall survival (OS), there were significant associations between central determinations of iPET ∆SUV with PFS/OS. In this patient cohort, we retrospectively compared local vs central iPET readings and evaluated associations between local imaging data and survival outcomes.

RESULTS

Agreement between local and central review was moderate (kappa = 0.53) for VSS and high (kappa = 0.81) for ∆SUV categories (<66% vs. ≥66%). ∆SUV ≥66% at iPET was significantly associated with PFS (p = 0.03) and OS (p = 0.002), but VSS was not. Associations with PFS/OS when applying local review vs central review were comparable.

CONCLUSIONS

These data suggest that local PET interpretation for response determination may be acceptable in clinical trials. Our findings also highlight limitations of VSS and call for incorporation of more objective measures of response assessment in clinical trials.

US Trends in Cholesterol Screening, Lipid Levels, and Lipid-Lowering Medication Use in US Adults, 1999 to 2018

Background Understanding current trends in cholesterol screening, lipid levels, and lipid management therapies may inform health policy and practice. Methods and Results In 50 928 US adult National Health and Nutrition Examination Survey (NHANES) participants, trends were assessed in cholesterol screening, mean levels of total cholesterol, triglycerides, low-density-lipoprotein cholesterol, and lipid-lowering medication use from 1999 through 2018. Point estimates were also calculated using the 2017 to March 2020 prepandemic data set. The age- and sex-adjusted proportion of having cholesterol screened within 5 years increased from 63.2% (95% CI, 60.0-66.3) in 1999 to 2000 to 72.5% (95% CI, 69.5-75.3) in 2017 to 2018 (P<0.001 for linear trend). Mean total cholesterol decreased from 203.3 mg/dL (95% CI, 201.0-205.7) in 1999 to 2000 to 188.4 mg/dL in 2017 to 2018 (95% CI, 185.4-191.5) (P<0.001 for nonlinear trend). The mean triglyceride level decreased from 121.3 mg/dL (95% CI, 116.4-126.4) in 1999 to 2000 to 91.4 mg/dL (95% CI, 88.4-94.6) in 2017 to 2018 (P<0.001 for nonlinear trend). Low-density lipoprotein cholesterol decreased from 127.9 mg/dL (95% CI, 125.3-130.5) in 1999 to 2000 to 111.7 mg/dL (95% CI, 109.0-114.4) in 2017 to 2018 (P<0.001 for nonlinear trend). Among statin-eligible US adults, the proportion of statin use increased from 14.9% (95% CI, 12.2-17.9) in 1999 to 2000 to 27.8% (95% CI, 23.0-33.2) in 2017 to 2018 (P<0.001 for nonlinear trend). Statin use increased in adults with diabetes aged 40 to 75 years from 21.4% in 1999 to 2000 to 51.9% in 2017 to 2018 (P<0.001 for overall linear trend). Statin use plateaued in all other groups. The proportions of using ezetimibe and proprotein convertase subtilisin/kexin type 9 inhibitors were 3.7% (95% CI, 1.3-9.8) and 0.03% (95% CI, 0.01-0.15) in 2017 to March 2020, respectively. Conclusions From 1999 through 2018, cholesterol screening increased while mean total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels decreased, with a modest increase in statin use and low uptake of nonstatin therapy in the US population.

Estimating the Incidence and Key Risk Factors of Cardiovascular Disease in Patients at High Risk of Imminent Fracture Using Routinely Collected Real-World Data From the UK

The objective of this work was to estimate the incidence rate of cardiovascular disease (CVD) events (myocardial infarction, stroke, or CVD death) at 1 year among three cohorts of patients at high risk of fracture (osteoporosis, previous fracture, and anti-osteoporosis medication) and to identify the key risk factors of CVD events in these three cohorts. To do so, this prospective cohort study used data from the Clinical Practice Research Datalink, a primary care database from United Kingdom. Major adverse cardiovascular events (MACE, a composite outcome for the occurrence of either myocardial infarction [MI], stroke, or CVD death) were identified in patients aged 50 years or older at high or imminent fracture risk identified in three different cohorts (not mutually exclusive): recently diagnosed with osteoporosis (OST, n = 65,295), incident fragility fracture (IFX, n = 67,065), and starting oral bisphosphonates (OBP, n = 145,959). About 1.90%, 4.39%, and 2.38% of the participants in OST, IFX, and OBP cohorts, respectively, experienced MACE events. IFX was the cohort with the higher risk: MACE incidence rates (cases/1000 person-years) were 19.63 (18.54-20.73) in OST, 52.64 (50.7-54.5) in IFX, and 26.26 (25.41-27.12) in OBP cohorts. Risk of MACE events at 1 year was predicted in the three cohorts. Models using a set of general, CVD, and fracture candidates selected by lasso regression had a good discrimination (≥70%) and internal validity and generally outperformed the models using only the CVD risk factors of general population listed in QRISK tool. Main risk factors common in all MACE models were sex, age, smoking, alcohol, atrial fibrillation, antihypertensive medication, prior MI/stroke, established CVD, glomerular filtration rate, systolic blood pressure, cholesterol levels, and number of concomitant medicines. Identified key risk factors highlight the differences of patients at high risk of fracture versus general population. Proposed models could improve prediction of CVD events in patients with osteoporosis in primary care settings. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Chemerin plasma levels are increased in COVID-19 patients and are an independent risk factor of mortality

Background

Chemerin is an extracellular protein with chemotactic activities and its expression is increased in various diseases such as metabolic syndrome and inflammatory conditions. Its role in lung pathology has not yet been extensively studied but both known pro- and anti-inflammatory properties have been observed. The aim of our study was to evaluate the involvement of the chemerin/ChemR23 system in the physiopathology of COVID-19 with a particular focus on its prognostic value.

Methods

Blood samples from confirmed COVID-19 patients were collected at day 1, 5 and 14 from admission to Erasme Hospital (Brussels – Belgium). Chemerin concentrations and inflammatory biomarkers were analyzed in the plasma. Blood cells subtypes and their expression of ChemR23 were determined by flow cytometry. The expression of chemerin and ChemR23 was evaluated on lung tissue from autopsied COVID-19 patients by immunohistochemistry (IHC).

Results

21 healthy controls (HC) and 88 COVID-19 patients, including 40 in intensive care unit (ICU) were included. Plasma chemerin concentration were significantly higher in ICU patients than in HC at all time-points analyzed (p<0.0001). Moreover, they were higher in deceased patients compared to survivors (p<0.05). Logistic univariate regression and multivariate analysis demonstrated that chemerin level at day 14 of admission was an independent risk factor for death. Accordingly, chemerin levels correlated with inflammatory biomarkers such as C-reactive protein and tumor necrosis factor α. Finally, IHC analysis revealed a strong expression of ChemR23 on smooth muscle cells and chemerin on myofibroblasts in advanced acute respiratory distress syndrome (ARDS).

Discussion

Increased plasma chemerin levels are a marker of severity and may predict death of COVID-19 patients. However, multicentric studies are needed, before chemerin can be considered as a biomarker of severity and death used in daily clinical practice. Further studies are also necessary to identify the precise mechanisms of the chemerin/ChemR23 system in ARDS secondary to viral pneumonia.

Delayed angiopoietin-2 blockade reduces influenza-induced lung injury and improves survival in mice

Influenza remains a major cause of death and disability with limited treatment options. Studies of acute lung injury have identified angiopoietin-2 (Ang-2) as a key prognostic marker and a potential mediator of Acute respiratory distress syndrome. However, the role of Ang-2 in viral pneumonia remains poorly defined. This study characterized the time course of lung Ang-2 expression in severe influenza pneumonia and tested the therapeutic potential of Ang-2 inhibition. We inoculated adult mice with influenza A (PR8 strain) and measured angiopoietin-1 (Ang-1), Ang-2, and Tie2 expressions during the evolution of inflammatory lung injury over the first 7 days post-infection (dpi). We tested a peptide-antibody inhibitor of Ang-2, L1-7, administered at 2, 4, and 6 dpi and measured arterial oxygen saturation, survival, pulmonary edema, inflammatory cytokines, and viral load. Finally, we infected primary human alveolar type II epithelial (AT2) cells grown in air-liquid interface culture with influenza and measured Ang-2 RNA expression. Influenza caused severe lung injury between 5 and 7 dpi in association with increased Ang-2 lung RNA and a dramatic increase in Ang-2 protein in bronchoalveolar lavage. Inhibition of Ang-2 improved oxygenation and survival and reduced pulmonary edema and alveolar-capillary barrier permeability to protein without major effects on inflammation or viral load. Finally, influenza increased the expression of Ang-2 RNA in human AT2 cells. The increased Ang-2 levels in the airspaces during severe influenza pneumonia and the improvement in clinically relevant outcomes after Ang-2 antagonism suggest that the Ang-1/Ang-2 Tie-2 signaling axis is a promising therapeutic target in influenza and potentially other causes of viral pneumonia.

Tumor-stroma ratio is associated with Miller-Payne score and pathological response to neoadjuvant chemotherapy in HER2-negative early breast cancer

The tumor-stroma ratio (TSR) has proven to be a strong prognostic factor in breast cancer, demonstrating better survival for patients with stroma-low tumors. Since the role of the TSR as a predictive marker for neoadjuvant chemotherapy outcome is yet unknown, this association was evaluated for HER2-negative breast cancer in the prospective DIRECT and NEOZOTAC trials. The TSR was assessed on 375 hematoxylin and eosin-stained sections of pre-treatment biopsies. Associations between the TSR and chemotherapy response according to the Miller-Payne (MP) grading system, and between the TSR and pathological response were examined using Pearson's chi-square, Cochran-Armitage test for trend and regression analyses. A stroma-low tumor prior to neoadjuvant chemotherapy was significantly associated with a higher MP score (P = .005). This relationship remained significant in the estrogen receptor (ER)-negative subgroup (P = .047). The univariable odds ratio (OR) of a stroma-low tumor on pathological complete response (pCR) was 2.46 (95% CI 1.34-4.51, P = .004), which attenuated to 1.90 (95% CI 0.85-4.25, P = .119) after adjustment for relevant prognostic factors. Subgroup analyses revealed an OR of 5.91 in univariable analyses for ER-negativity (95% CI 1.19-29.48, P = .030) and 1.48 for ER-positivity (95% CI 0.73-3.01, P = .281). In conclusion, a low amount of stroma on pre-treatment biopsies is associated with a higher MP score and pCR rate. Therefore, the TSR is a promising biomarker in predicting neoadjuvant treatment outcome. Incorporating this parameter in routine pathological diagnostics could be worthwhile to prevent overtreatment and undertreatment.

Successful Prediction of Human Steady-State Unbound Brain-to-Plasma Concentration Ratio of P-gp Substrates Using the Proteomics-Informed Relative Expression Factor Approach

In order to optimize central nervous system (CNS) drug development, accurate prediction of the drug's human steady-state unbound brain interstitial fluid-to-plasma concentration ratio (K_p,uu,brain ) is critical, especially for drugs that are effluxed by the multiple drug resistance transporters (e.g., P-glycoprotein, P-gp). Due to lack of good in vitro human blood-brain barrier models, we and others have advocated the use of a proteomics-informed relative expressive factor (REF) approach to predict K_p,uu,brain . Therefore, we tested the success of this approach in humans, with a focus on P-gp substrates, using brain positron emission tomography imaging data for verification. To do so, the efflux ratio (ER) of verapamil, N-desmethyl loperamide, and metoclopramide was determined in human P-gp-transfected MDCKII cells using the Transwell assay. Then, using the ER estimate, K_p,uu,brain of the drug was predicted using REF (ER approach). Alternatively, in vitro passive and P-gp-mediated intrinsic clearances (CLs) of these drugs, estimated using a five-compartmental model, were extrapolated to in vivo using REF (active CL) and brain microvascular endothelial cells protein content (passive CL). The ER approach successfully predicted K_p,uu,brain of all three drugs within twofold of observed data and within 95% confidence interval of the observed data for verapamil and N-desmethyl loperamide. Using the in vitro-to-in vivo extrapolated clearance approach, K_p,uu,brain was reasonably well predicted but not the brain unbound interstitial fluid drug concentration-time profile. Therefore, we propose that the ER approach be used to predict K_p,uu,brain of CNS candidate drugs to enhance their success in development.