Lesion-level heterogeneity of radiologic progression in patients treated with pembrolizumab.

BACKGROUND: Disease progression is often considered a binary state reflecting presence or absence of response. Meaningful heterogeneity between metastatic sites of a given patient may exist, however, and may impact therapeutic outcomes. To characterize the heterogeneity of progression with immunotherapy, we evaluated lesion-level dynamics of pembrolizumab-treated patients across three tumor types. PATIENTS AND METHODS: Individual metastatic lesion dynamics were analyzed retrospectively in patients with advanced melanoma, non-small-cell lung cancer (NSCLC), and gastric or gastroesophageal junction (G/GEJ) cancer who received pembrolizumab in KEYNOTE-001 or KEYNOTE-059. Primary progression was defined as radiologic progression as per RECIST v1.1 occurring at the first on-treatment study scan (∼9-12 weeks, +2-week window) and secondary progression as progression occurring beyond the first scan (∼14 weeks and beyond). The change in sum of target lesions and of individual lesions was examined, as were patterns and timing of progression. RESULTS: 9239 individual lesions from 1194 patients were analyzed. Among patients with primary progression [39% (200/511) of patients with melanoma, 41% (179/432) with NSCLC, 61% (154/251) with G/GEJ cancer], most patients (51%-63%) had a mixture of growing, stable, and shrinking lesions. Despite overall primary progression, a minority of patients (19%-25%) had tumor growth at every metastatic site and 17%-32% had ≥1 shrinking lesion. Among patients with secondary progression [22% (113/511) of patients with melanoma, 27% (117/432) with NSCLC, 18% (44/251) with G/GEJ cancer], few patients had rebound growth (>20% increase in diameter from nadir) in all lesions whereas the majority (74%-84%) had sustained regression in ≥1 lesion. CONCLUSIONS: Lesion-level heterogeneity at the time of disease progression was common in pembrolizumab-treated patients, with many patients demonstrating ongoing disease control in a subset of tumor sites. These results may inform clinical decision-making, trial design, and tumor sampling in the future.

Systematic evaluation of pembrolizumab dosing in patients with advanced non-small-cell lung cancer.

BACKGROUND: In the phase I KEYNOTE-001 study, pembrolizumab demonstrated durable antitumor activity in patients with advanced non-small-cell lung cancer (NSCLC). We sought to characterize the relationship between pembrolizumab dose, exposure, and response to define an effective dose for these patients. PATIENTS AND METHODS: Patients received pembrolizumab 2 mg/kg every 3 weeks (Q3W) (n = 55), 10 mg/kg Q3W (n = 238), or 10 mg/kg Q2W (n = 156). Response (RECIST v1.1) was assessed every 9 weeks. The relationship between the estimated pembrolizumab area under the concentration-time curve at steady state over 6 weeks (AUCss-6weeks) and the longitudinal change in tumor size (sum of longest diameters) was analyzed by regression and non-linear mixed effects modeling. This model was simultaneously fit to all tumor size data, then used to simulate response rates, normalizing the trial data across dose for prognostic covariates (tumor PD-L1 expression and EGFR mutation status). The exposure-safety relationship was assessed by logistic regression of pembrolizumab AUCss-6weeks versus occurrence of adverse events (AEs) of interest based on their immune etiology. RESULTS: Overall response rates were 15% [95% confidence interval (CI) 7%-28%] at 2 mg/kg Q3W, 25% (18%-33%) at 10 mg/kg Q3W, and 21% (95% CI 14%-30%) at 10 mg/kg Q2W. Regression analyses of percentage change from baseline in tumor size versus AUCss-6weeks indicated a flat relationship (regression slope P > 0.05). Simulations showed the exposure-response relationship to be similarly flat, thus indicating that the lowest evaluated dose of 2 mg/kg Q3W to likely be at or near the efficacy plateau. Exposure-safety analysis showed the AE incidence to be similar among the clinically tested doses. CONCLUSIONS: No significant exposure dependency on efficacy or safety was identified for pembrolizumab across doses of 2-10 mg/kg. These results support the use of a 2 mg/kg Q3W dosage in patients with previously treated, advanced NSCLC. CLINICALTRIALSGOV REGISTRY: NCT01295827.

Auditory input enhances somatosensory encoding and tactile goal-directed behavior.

The capacity of the brain to encode multiple types of sensory input is key to survival. Yet, how neurons integrate information from multiple sensory pathways and to what extent this influences behavior is largely unknown. Using two-photon Ca2+ imaging, optogenetics and electrophysiology in vivo and in vitro, we report the influence of auditory input on sensory encoding in the somatosensory cortex and show its impact on goal-directed behavior. Monosynaptic input from the auditory cortex enhanced dendritic and somatic encoding of tactile stimulation in layer 2/3 (L2/3), but not layer 5 (L5), pyramidal neurons in forepaw somatosensory cortex (S1). During a tactile-based goal-directed task, auditory input increased dendritic activity and reduced reaction time, which was abolished by photoinhibition of auditory cortex projections to forepaw S1. Taken together, these results indicate that dendrites of L2/3 pyramidal neurons encode multisensory information, leading to enhanced neuronal output and reduced response latency during goal-directed behavior.

Nutritive Importance and Therapeutics Uses of Three Different Varieties (Murraya koenigii, Micromelum minutum, and Clausena indica) of Curry Leaves: An Updated Review.

Murraya koenigii (M. koenigii), Micromelum minutum (M. minutum), and Clausena indica (C. indica) are three varieties of curry leaves in the family Rutaceae. They have been widely used in Ayurvedic medicine worldwide in the treatment and prevention of various diseases. Earlier findings provide strong evidence to support the three curry leaf species' potent pharmaceutical and biological effects, including antioxidant, antidiabetic, anti-inflammatory, and antitumor activities. Various parts of these plants, such as leaves, seeds, flowers, and fruit, contain constituents responsible for the modulation of numerous biological processes. Leading constituents of curry leaves play a crucial role in diabetic and anticancer management by regulating various molecular pathways, including Bcl-2, Bax, NF-κB, and TNFα, according to in vitro and in vivo models established. Therefore, this review summarizes the current knowledge on research achievements made in terms of phytoconstituents, their structures, biological activities, and pharmacological actions with clinical studies of curry leaves up to date. The review also emphasizes the necessity for comprehensive research studies on the pharmacological actions and the mechanisms of selected phytochemicals of M. koenigii, M. minutum, and C. indica to validate their efficacy as potent herbal remedies for many ailments.

Phytochemical screening, total polyphenol, flavonoid content, in vitro antioxidant and antibacterial activities of Sri Lankan varieties of Murraya koenigii and Micromelum minutum leaves.

The use of plant materials in traditional medicine as a significant ingredient in synthesizing drugs in the form of decoctions had played a vital role due to their potential therapeutic action. The curry leaves, Murraya koenigii, and Micromelum minutum are two most common aromatic herbs widespread in Sri Lanka and many other Asian countries. They are rich in nutrition and exert several medicinal properties such as antidiabetic, antioxidant, antimicrobial, anti-inflammatory, and anti-carcinogenic due to various essential phytochemicals, minerals, and trace minerals. In this study, we determined the proximate composition, in vitro antioxidant activity, total phenol (TPC), flavonoid content (TFC), and antibacterial activity in both species using standard methods. Results showed that both species varied greatly in nutritional composition, antioxidant, and antibacterial activities. The nutrient composition in terms of ash, crude protein, and fat was significantly high in M. koenigii based on dry weight basis. In vitro antioxidant potential of M. koenigii and M. minutum was evaluated by means of the DPPH radical scavenging assay, and the IC50 values of M. koenigii and M. minutum were 107 ± 2 µg/mL and 208 ± 4 µg/mL, respectively. The TPC and TFC of M. koenigii were 101 ± 1 mg GAE/g and 9.75 ± 0.05 mg QE/g, and M. minutum were 80 ± 2 mg GAE/g and 9.16 ± 0.02 mg QE/g respectively. The antibacterial study was assessed against three bacterial strains. The study showed the highest inhibitory activity for M. koenigii and M. minutum against Staphylococcus aureus and Escherichia coli, respectively at 1.0 mg/mL concentration. The study indicated that M. koenigii possessed a significantly high TPC, and TFC correlated with higher antibacterial and antioxidant activity than M. minutum.

Using Model-Based "Learn and Confirm" to Reveal the Pharmacokinetics-Pharmacodynamics Relationship of Pembrolizumab in the KEYNOTE-001 Trial.

Evaluation of pharmacokinetic/pharmacodynamic (PK/PD) properties played an important role in the early clinical development of pembrolizumab. Because analysis of data from a traditional 3 + 3 dose-escalation design revealed several critical uncertainties, a model-based approach was implemented to better understand these properties. Based on anticipated scenarios for potency and PK nonlinearity, a follow-up study was designed and thoroughly evaluated. Execution of 14,000 virtual trials led to the selection and implementation of a robust design that extended the low-dose range by 200-fold. Modeling of the resulting data demonstrated that pembrolizumab PKs are nonlinear at <0.3 mg/kg every 3 weeks, but linear in the clinical dose range. Saturation of ex vivo target engagement in blood began at ≥1 mg/kg every 3 weeks, and a steady-state dose of 2 mg/kg every 3 weeks was needed to reach 95% target engagement, supporting examination of 2 mg/kg every 3 weeks in ongoing trials in melanoma and other advanced cancers.

Translational Pharmacokinetic/Pharmacodynamic Modeling of Tumor Growth Inhibition Supports Dose-Range Selection of the Anti-PD-1 Antibody Pembrolizumab.

Pembrolizumab, a humanized monoclonal antibody against programmed death 1 (PD-1), has a manageable safety profile and robust clinical activity against advanced malignancies. The lowest effective dose for evaluation in further dose-ranging studies was identified by developing a translational model from preclinical mouse experiments. A compartmental pharmacokinetic model was combined with a published physiologically based tissue compartment, linked to receptor occupancy as the driver of observed tumor growth inhibition. Human simulations were performed using clinical pharmacokinetic data, literature values, and in vitro parameters for drug distribution and binding. Biological and mathematical uncertainties were included in simulations to generate expectations for dose response. The results demonstrated a minimal increase in efficacy for doses higher than 2 mg/kg. The findings of the translational model were successfully applied to select 2 mg/kg as the lowest dose for dose-ranging evaluations.

Model-Based Characterization of the Pharmacokinetics of Pembrolizumab: A Humanized Anti-PD-1 Monoclonal Antibody in Advanced Solid Tumors.

Pembrolizumab, a potent antibody against programmed death 1 (PD-1) receptor, has shown robust antitumor activity and manageable safety in patients with advanced solid tumors. Its pharmacokinetic (PK) properties were analyzed with population PK modeling using pooled data from the KEYNOTE-001, -002, and -006 studies of patients with advanced melanoma, non-small cell lung cancer (NSCLC), and other solid tumor types. Pembrolizumab clearance was low and the volume of distribution small, as is typical for therapeutic antibodies. Identified effects of sex, baseline Eastern Cooperative Oncology Group performance status, measures of renal and hepatic function, tumor type and burden, and prior ipilimumab treatment on pembrolizumab exposure were modest and lacked clinical significance. Furthermore, simulations demonstrated the model has robust power to detect clinically relevant covariate effects on clearance. These results support the use of the approved pembrolizumab dose of 2 mg/kg every 3 weeks without dose adjustment in a variety of patient subpopulations.

Pembrolizumab: Role of Modeling and Simulation in Bringing a Novel Immunotherapy to Patients With Melanoma.

Recently, immunotherapy has yielded promising results in several cancer types. Contrary to the established classical chemotherapy-dosing paradigm, a maximum tolerated dose approach does not always produce better clinical outcomes for novel targeted therapies, as their efficacy is frequently robust at pharmacologically active doses below the maximum tolerated dose. Integrated safety and efficacy assessments are needed to inform clinical dose and trial design, and to support an early identification of potentially safe and efficacious combination treatments.

Population Pharmacokinetic/Pharmacodynamic Modeling of Tumor Size Dynamics in Pembrolizumab-Treated Advanced Melanoma.

Pembrolizumab is a potent immune-modulating antibody active in advanced melanoma, as demonstrated in the KEYNOTE-001, -002, and -006 studies. Longitudinal tumor size modeling was pursued to quantify exposure-response relationships for efficacy. A mixture model was first developed based on an initial dataset from KEYNOTE-001 to describe four patterns of tumor growth and shrinkage. For subsequent analyses, tumor size measurements were adequately described by a single consolidated model structure that captured continuous tumor size with a combination of growth and regression terms, as well as a fraction of tumor responsive to therapy. This revised model structure provided a framework to efficiently evaluate the impact of covariates and pembrolizumab exposure. Both models indicated that exposure to the drug was not a significant predictor of tumor size response, demonstrating that the dose range evaluated (2 and 10 mg/kg every 3 weeks) is likely near or at the plateau of maximal response.

A rare cervical spine abnormality associated with neurofibromatosis.

Spinal abnormalities such as kyphoscoliosis and vertebral scalloping are frequent occurrences in type 1 neurofibromatosis (NF1). We report this rare case of posterior displacement of C3 vertebral body into the spinal canal causing severe cord compression associated with neurofibromatosis in a 13-year old girl. She underwent anterior excision of C3 vertebral body, bone graft and fixation of C2- C4, with improvement of her symptoms.

Population pharmacokinetic-pharmacodynamic modeling of moxonidine using 24-hour ambulatory blood pressure measurements.

OBJECTIVES: To develop a model for 24-hour ambulatory blood pressure measurements (ABPM) that can be applied in a pharmacokinetic-pharmacodynamic model. METHODS: Four different data sets were prepared from 2 studies to accommodate different modeling strategies. In study A, a double-blind placebo-controlled study in 47 patients, 24-hour ABPM profiles (74 to 99 measurements per profile) were obtained during the placebo run-in phase and after 3, 5, and 11 weeks during the treatment. Three to 5 plasma samples were taken. Cosine and polynomial models were evaluated to describe the circadian rhythm in blood pressure based on 3 data sets (1: only run-in data; 2: only placebo data; 3: all data). In study B, a double-blind placebo-controlled study in 94 patients, two 24-hour ABPM profiles per patient (during placebo run-in and after 8 weeks) were recorded and randomly reduced to 15 measurements per profile to evaluate the robustness of the baseline model. RESULTS: The mean moxonidine clearance was 35 L/h, and the volume of distribution was 132 L. The final baseline model consisted of 2 cosine terms with fixed-effect parameters for rhythm-adjusted 24-hour mean blood pressure, amplitude, phase, and period; random-effect parameters for interindividual variability in rhythm-adjusted 24-hour mean, amplitude, and clock time; and interoccasion variability in rhythm-adjusted 24-hour mean and clock time. The final baseline model was combined with an Emax model for the drug effect. An effect compartment was used (kco = 0.198 h-1). The maximum decrease in diastolic blood pressure (Emax) was 16.7%, and EC50 was 0.945 microgram/L. CONCLUSION: The pharmacokinetic-pharmacodynamic model for 24-hour ABPM can be used to estimate the concentration-effect relationship of antihypertensive drugs.

Comparison of manual versus ambulatory blood pressure measurements with pharmacokinetic-pharmacodynamic modeling of antihypertensive compounds: application to moxonidine.

OBJECTIVES: To compare the results of the pharmacokinetic-pharmacodynamic analyses of 24-hour ambulatory blood pressure measurements and manual blood pressure data in patients receiving moxonidine. METHODS: 32 patients with borderline to mild-to-moderate hypertension were enrolled in a double-blind, placebo-controlled phase II study. After receiving placebo for 1 week (run-in phase), the patients were randomly allocated to the placebo or the 0.6-, 0.9-, or 1.2-mg dose groups. Placebo and moxonidine were administered once daily for 1 week (drug-treatment phase). Four 24-hour ambulatory blood pressure measurement profiles were obtained for each individual. Plasma samples (n = 9) and four measurements of manual blood pressure were taken at the start and end of the drug-treatment phase. Two additional manual blood pressure measurements were taken during the run-in and drug-treatment phases. RESULTS: Pharmacokinetics was described by a one-compartment model. For the 24-hour ambulatory blood pressure measurements, baseline circadian patterns were described with a two-cosine function model that included interindividual and interoccasion variability. Pharmacodynamics was described with use of an effect-compartment model [k(e0) = 0.37 (1/h)] and an Emax model. For diastolic blood pressure the maximum drug-induced decrease (Emax) was 30.9 mm Hg and the steady-state plasma drug concentration eliciting half of maximum effect (C50) was 1.33 microg/L. Interindividual variability was estimated for ke0 (24.8%) and Emax (33.3%). For the manual blood pressure measurements, data was described by a time-invariant baseline model combined with an effect-compartment model and an Emax model. Mean population estimates were in agreement with those obtained during the analysis of 24-hour ambulatory blood pressure measurements. However, interindividual variability could be estimated for the baseline parameter only. CONCLUSIONS: Although similar typical population estimates for the drug action-related parameters were obtained with use of manual blood pressure data and 24-hour ambulatory blood pressure measurements, the latter allowed for a more detailed description of the individual pharmacodynamic profiles because interindividual variability in pharmacodynamic parameters could be estimated together with increased precision in parameter estimates.

A new way to use the Ishihara test.

The Ishihara plates are widely used as a test for colour vision. Originally designed for the purpose of detecting congenital red-green colour blindness, the test also has some value in demonstrating acquired colour vision defects. There are, however, several disadvantages in the present arrangement of the plates. A modification of the test, involving the rearrangement of the order of the plates, is presented which, together with a new recording chart, simplifies both the administration and the interpretation of the test.

Automated tritan discrimination sensitivity: a new clinical technique for the effective screening of severe diabetic retinopathy.

We have developed and extensively assessed an automated chromatic discrimination test which can be used to screen effectively a diabetic population for sight threatening diabetic eye disease. Equiluminant, sinusoidal, low spatial frequency, chromatic gratings are produced along a tritan confusion axis under computer software control on a high resolution CRT. The correct position of the tritan axis in colour space was calibrated using subjects whilst they were transiently tritanopic. The minimum amplitude about a neutral "grey point" along the tritan confusion axis at which a subject can just distinguish a grating is found using a double staircase reversal algorithm. This measure is taken as the Tritan Discrimination Sensitivity and it is this that we use to flag those diabetics with severe diabetic retinopathy. This computerised tritan discrimination test is quick, non-invasive, easy to operate, inexpensive and reliable. The test-retest reliability coefficient (rho) is 0.92. The tritan discrimination test effectively identifies those diabetics who have or are most at risk of developing severe diabetic retinopathy. The sensitivity of the test for the detection of maculopathy, ischaemic retinopathy (pre-proliferative), and proliferative retinopathy is 97%, 65%, and 93%, respectively. The corrected specificity of the test is 83%. We conclude that the tritan discrimination test has potential for use as a valuable screening tool for the early detection and treatment of severe diabetic retinopathy.

Implementation of quantitative and systems pharmacology in large pharma.

Quantitative and systems pharmacology concepts and tools are the foundation of the model-informed drug development paradigm at Merck for integrating knowledge, enabling decisions, and enhancing submissions. Rigorous prioritization of modeling and simulation activities has enabled key drug development decisions and led to a high return on investment through significant cost avoidance. Critical factors for the successful implementation, examples on impact on decision making with associated return of investment, and drivers for continued success are discussed.

Characterising effects of impact velocity on brain and behaviour in a model of diffuse traumatic axonal injury.

The velocity of impact between an object and the human head is a critical factor influencing brain injury outcomes but has not been explored in any detail in animal models. Here we provide a comprehensive overview of the interplay between impact velocity and injury severity in a well-established weight-drop impact acceleration (WDIA) model of diffuse brain injury in rodents. We modified the standard WDIA model to produce impact velocities of 5.4, 5.85 and 6.15 m/s while keeping constant the weight and the drop height. Gradations in impact velocity produced progressive degrees of injury severity measured behaviourally, electrophysiologically and anatomically, with the former two methods showing greater sensitivity to changes in impact velocity. There were impact velocity-dependent reductions in sensorimotor performance and in cortical depth-related depression of sensory cortex responses; however axonal injury (demonstrated by immunohistochemistry for ß-amyloid precursor protein and neurofilament heavy-chain) was discernible only at the highest impact velocity. We conclude that the WDIA model is capable of producing graded axonal injury in a repeatable manner, and as such will prove useful in the study of the biomechanics, pathophysiology and potential treatment of diffuse axonal injury.

An unusual case of adult onset progressive heterotopic ossification suggesting a variant form of fibrodysplasia ossificans progressiva.

Progressive heterotopic ossification (HO) is a rare disease of genetic inheritance. Fibrodysplasia ossificans progressiva (FOP) is an identified debilitating subcategory in which anomalous ossification usually begins in childhood. Congenital big toe anomalies and specific patterns of progression of ossification confirm the classic disease. Adult onset disease is extremely rare. The mechanism of disease progression is still unclear, and there is no consensus on the treatment modalities. We report a 47-year-old man with adult-onset progressive HO around the bilateral pelvic and shoulder girdles and thoracolumbar spine, which suggested a variant form of FOP. Although surgical excision is considered counterproductive in FOP, our patient showed improvement in his shoulder movement following surgery. Other management strategies, including surgery around the hips, indomethacin prophylaxis, irradiation and bisphosphonate therapy, did not improve his range of movement or disease progression.