Gemogenovatucel-T (Vigil): bi-shRNA plasmid-based targeted immunotherapy.

We describe in this review the historical evidence leading up to the concept and design of Vigil and subsequent clinical applications including safety and efficacy in a randomized, controlled Phase IIB trial. Vigil (gemogenovatucel-T) is a unique triple function targeted immunotherapy that demonstrates preclinical and clinical systemic anticancer activity. Construction of Vigil involves harvest of autologous malignant tissue for neoantigen targeting (ideally containing clonal neoantigens) followed by a two-day process involving transfection with a plasmid to provide a permissive 'training environment' for the patient's immune system. Transfected plasmid components contain an expressive human GMCSF DNA segment to enhance anticancer immune functional response and a second component expressing bi-shRNAfurin which reduces TGFß isomers (TGFß1 and TGFß2) thereby reducing cancer inhibition of the targeted immune response. Results generated to date justify advancement to confirmatory clinical trials supporting product regulatory approval.

Vigil is an anticancer treatment that employs three methods of enhancing the body's immune system to identify and kill cancer cells. The construction of Vigil involves cancer cells from the same person being treated (personalized therapy) in combination with added anticancer genetic signals to enhance the number and function anti-anticancer immune cells and to guide the immune cells to the cancer and not to normal organs of the body. In this manner, an army of immune cells are created that can move to attacking the cancer using blood vessels to get to the cancer anywhere it tries to grow in the body. One study (Phase I) performed with this product to determine safety and dose range demonstrated an optimal dose and schedule. Another study (Phase IIA) showed initial clinical benefit. A third more complex study (Phase IIB) in patients treated with Vigil compared with standard of care without Vigil demonstrated the ability to prolong the patients life and time without their cancer getting worse without any significant side effects associated with the treatment in a unique subset of ovarian cancer patients, those with the ability to repair their DNA. Based on the composite of these results, Vigil is an attractive targeted immunotherapy justified for late-stage clinical testing.

Comparison of ANP and BNP Granular Density in Atria of Rats After Physiological and Pathological Hypertrophy.

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are cardiac hormones located in atria granules. Both peptides respond to cardiac pressure and volume dynamics and accordingly serve as translation biomarkers for the clinical treatment of heart failure. Serum ANP and BNP play central secretary roles in blood pressure and cardiac output regulation and have proven utility as differential biomarkers of cardiovascular proficiency and drug-induced maladaptation, yet both peptides are impervious to exercise-induced hypertrophy. We employed immunoelectron microscopy to examine the effects of 28 days of chronic swim exercise or administration of a PPARγ agonist on atrial granules and their stored natriuretic peptides in Sprague Dawley rats. Chronic swimming and drug treatment both resulted in a 15% increase in heart weight compared with controls, with no treatment effects on perinuclear granule area in the left atria (LAs). Drug treatment resulted in larger size granules with greater BNP density in the right atria. Comparing swimming and PPARγ agonist treatment effects on ANP:BNP granule density ratios between atrial chambers revealed a shift toward a greater proportion of ANP than BNP in LAs of swim-trained rats. These data suggest a distinction in the population of ANP and BNP after chronic swim or PPARγ that makes it a novel metric for the differentiation of pathological and physiological hypertrophy.

Evaluating Associations Between Nonclinical Cardiovascular Functional Endpoints and Repeat-dose Cardiovascular Toxicity in the Beagle Dog: A Cross-company Initiative.

Integrating nonclinical in vitro, in silico, and in vivo datasets holistically can improve hazard characterization and risk assessment. In pharmaceutical development, cardiovascular liabilities are a leading cause of compound attrition. Prior to clinical studies, functional cardiovascular data are generated in single-dose safety pharmacology telemetry studies, with structural pathology data obtained from repeat-dose toxicology studies with limited concurrent functional endpoints, eg, electrocardiogram via jacketed telemetry. Relationships between datasets remain largely undetermined. To address this gap, a cross-pharma collaboration collated functional and structural data from 135 compounds. Retrospective functional data were collected from good laboratory practice conscious dog safety pharmacology studies: effects defined as hemodynamic blood pressure or heart rate changes. Morphologic pathology findings (mainly degeneration, vacuolation, inflammation) from related toxicology studies in the dog (3-91 days repeat-dosing) were reviewed, harmonized, and location categorized: cardiac muscle (myocardium, epicardium, endocardium, unspecified), atrioventricular/aortic valves, blood vessels. The prevalence of cardiovascular histopathology changes was 11.1% of compounds, with 53% recording a functional blood pressure or heart rate change. Correlations were assessed using the Mantel-Haenszel Chi-square trend test, identifying statistically significant associations between cardiac muscle pathology and (1) decreased blood pressure, (2) increased heart rate, and between cardiovascular vessel pathology and increased heart rate. Negative predictive values were high, suggesting few compounds cause repeat-dose cardiovascular structural change in the absence of functional effects in single-dose safety pharmacology studies. Therefore, observed functional changes could prompt moving (sub)chronic toxicology studies forward, to identify cardiovascular liabilities earlier in development, and reduce late-stage attrition.

Serum Natriuretic Peptides as Differential Biomarkers Allowing for the Distinction between Physiologic and Pathologic Left Ventricular Hypertrophy.

Given the proven utility of natriuretic peptides as serum biomarkers of cardiovascular maladaptation and dysfunction in humans and the high cross-species sequence conservation of atrial natriuretic peptides, natriuretic peptides have the potential to serve as translational biomarkers for the identification of cardiotoxic compounds during multiple phases of drug development. This work evaluated and compared the response of N-terminal proatrial natriuretic peptide (NT-proANP) and N-terminal probrain natriuretic peptide (NT-proBNP) in rats during exercise-induced and drug-induced increases in cardiac mass after chronic swimming or daily oral dosing with a peroxisome proliferator-activated receptor γ agonist. Male Sprague-Dawley rats aged 8 to 10 weeks were assigned to control, active control, swimming, or drug-induced cardiac hypertrophy groups. While the relative heart weights from both the swimming and drug-induced cardiac hypertrophy groups were increased 15% after 28 days of dosing, the serum NT-proANP and NT-proBNP values were only increased in association with cardiac hypertrophy caused by compound administration. Serum natriuretic peptide concentrations did not change in response to adaptive physiologic cardiac hypertrophy induced by a 28-day swimming protocol. These data support the use of natriuretic peptides as fluid biomarkers for the distinction between physiological and drug-induced cardiac hypertrophy.

Evaluation of Cardiac Toxicity Biomarkers in Rats from Different Laboratories.

There is a great need for improved diagnostic and prognostic accuracy of potential cardiac toxicity in drug development. This study reports the evaluation of several commercially available biomarker kits by 3 institutions (SRI, Eli Lilly, and Pfizer) for the discrimination between myocardial degeneration/necrosis and cardiac hypertrophy as well as the assessment of the interlaboratory and interplatform variation in results. Serum concentrations of natriuretic peptides (N-terminal pro-atrial natriuretic peptide [NT-proANP] and N-terminal pro-brain natriuretic peptide [NT-proBNP]), cardiac and skeletal troponins (cTnI, cTnT, and sTnI), myosin light chain 3 (Myl3), and fatty acid binding protein 3 (FABP3) were assessed in rats treated with minoxidil (MNX) and isoproterenol (ISO). MNX caused increased heart-to-body weight ratios and prominent elevations in NT-proANP and NT-proBNP concentrations detected at 24-hr postdose without elevation in troponins, Myl3, or FABP3 and with no abnormal histopathological findings. ISO caused ventricular leukocyte infiltration, myocyte fibrosis, and necrosis with increased concentrations of the natriuretic peptides, cardiac troponins, and Myl3. These results reinforce the advantages of a multimarker strategy in elucidating the underlying cause of cardiac insult and detecting myocardial tissue damage at 24-hr posttreatment. The interlaboratory and interplatform comparison analyses also showed that the data obtained from different laboratories and platforms are highly correlated and reproducible, making these biomarkers widely applicable in preclinical studies.

Cross-laboratory analytical validation of the cardiac biomarker NT-proANP in rat.

INTRODUCTION: Natriuretic peptides, including N-terminal-proatrial natriuretic peptide (NT-proANP) are cardiac hormones that are produced in response to myocardial stretch and have been used in rats and humans as blood based functional cardiac biomarkers. There are limited validation data of these assays in rats and therefore the Predictive Safety Testing Consortium, Cardiac Hypertrophy Working Group (PSTC-CHWG) performed a cross-laboratory (5 laboratories) analytical evaluation of a commercially available NT-proANP ELISA for use with rat samples. METHODS: Serum samples were collected from normal Sprague Dawley (SD) rats and were spiked with kit calibrator material or rat heart tissue extracts to provide specimens for the validation. In addition, the cardiotoxicant, isoproterenol, was used to induce elevated endogenous NT-proANP levels in a subgroup of rats for additional validation specimens. The Biomedica™ (BI-20892, Vienna, Austria) proANP (1-98) enzyme-linked immunoabsorbent assay (ELISA) kit was used to measure NT-proANP. Intra-assay and inter-assay precisions, accuracy, sample linearity, recovery, limit of detection, upper and lower limits of quantitation (ULOQ and LLOQ, respectively), sample-freeze/thaw stability and stored sample stability were assessed and compared to pre-determined acceptance criteria. RESULTS: The majority of the experimental assessments met the established validation criteria, however there were individual results that did not meet these standards. Overall, acceptable intra- and inter-assay precisions and accuracies as well as inter-laboratory precision and accuracy were demonstrated. Linearity and recovery values fell within the pre-determined acceptance criteria, samples remained stable for up to three freeze-thaw cycles and frozen samples were stable at ~-70 °C for 12 months. The limit of detection (LOD) and LLOQ and ULOQ were similar to those specified by the manufacturer. DISCUSSION: Overall, the assay was demonstrated to be technically adequate for the detection of NT-proANP serum levels in SD rats.

Natriuretic Peptides as Cardiovascular Safety Biomarkers in Rats: Comparison With Blood Pressure, Heart Rate, and Heart Weight.

Cardiovascular (CV) toxicity is an important cause of failure during drug development. Blood-based biomarkers can be used to detect CV toxicity during preclinical development and prioritize compounds at lower risk of causing such toxicities. Evidence of myocardial degeneration can be detected by measuring concentrations of biomarkers such as cardiac troponin I and creatine kinase in blood; however, detection of functional changes in the CV system, such as blood pressure, generally requires studies in animals with surgically implanted pressure transducers. This is a significant limitation because sustained changes in blood pressure are often accompanied by changes in heart rate and together can lead to cardiac hypertrophy and myocardial degeneration in animals, and major adverse cardiovascular events (MACE) in humans. Increased concentrations of NPs in blood correlate with higher risk of cardiac mortality, all-cause mortality, and MACE in humans. Their utility as biomarkers of CV function and toxicity in rodents was investigated by exploring the relationships between plasma concentrations of NTproANP and NTproBNP, blood pressure, heart rate, and heart weight in Sprague Dawley rats administered compounds that caused hypotension or hypertension, including nifedipine, fluprostenol, minoxidil, L-NAME, L-thyroxine, or sunitinib for 1-2 weeks. Changes in NTproANP and/or NTproBNP concentrations were inversely correlated with changes in blood pressure. NTproANP and NTproBNP concentrations were inconsistently correlated with relative heart weights. In addition, increased heart rate was associated with increased heart weights. These studies support the use of natriuretic peptides and heart rate to detect changes in blood pressure and cardiac hypertrophy in short-duration rat studies.

Biomarkers of exocrine pancreatic injury in 2 rat acute pancreatitis models.

UNLABELLED: Consistent, sensitive biomarkers of exocrine pancreatic injury (EPIJ) in animal models and humans have historically represented a poorly met need for investigators and clinicians. EXPERIMENTAL DESIGN: Sprague-Dawley CD/International Genetic Standard system (IGS) rats were administered cerulein or cyanohydroxybutene (CHB) to induce EPIJ. Serum samples were taken at time points between 1- and 168-hr postinjection (PI), and rats were sacrificed between 24- and 168-hr PI. METHOD: We investigated a series of serum-based biomarkers including amylase, lipase, pancreas-enriched microRNAs (miRs) and inflammation biomarkers compared with concurrent hematology and pancreatic histology. RESULTS AND CONCLUSION: Microscopic EPIJ was not associated with consistent changes in hematology or inflammation biomarkers. Increased severity scores for EPIJ correlated with increased amylase and lipase values, although severity of EPIJ did not always correlate with the magnitude of enzyme increases. Microscopic EPIJ was most severe at 24 to 48 hr; increases in miR-216a (32-fold) and miR-375 (23-fold) were present at 24 hr and, along with enzymes, were normalized by 48 hr in the cerulein study. MiRs-216a and 375 were increased by ∼800- and 500-fold, respectively, at 24 hr while miR-375 remained elevated until 72 hr in the CHB study. Impact statement: Pancreas-enriched miRs hold promise as novel serum-based biomarkers for EPIJ.

Detection of left ventricular hypertrophy in rats administered a peroxisome proliferator-activated receptor alpha/gamma dual agonist using natriuretic peptides and imaging.

Chronic treatment with suprapharmacologic doses of peroxisome proliferator-activated receptor (PPAR) agonists has a known potential for causing left ventricular hypertrophy (LVH). The mechanism by which LVH develops is not well understood nor are biomarkers of it well characterized. Natriuretic peptides are important regulators of cardiac growth, blood volume, and arterial pressure and may be useful biomarkers of LVH and hemodynamic changes that precede it. We measured amino-terminal pro-atrial natriuretic peptide (NTproANP), amino-terminal pro-brain natriuretic peptide (NTproBNP), and cardiac troponin I (cTnI) concentrations in serum and plasma, as well as transcripts in left ventricular heart tissue for atrial natriuretic peptide precursor (Nppa), brain natriuretic peptide precursor (Nppb), and myosin heavy chain-beta (Myh7) as potential biomarkers of LVH induced by a PPARalpha/gamma dual agonist in Sprague-Dawley rats. We used magnetic resonance imaging, echocardiography, and hemodynamics to identify structural and functional cardiovascular changes related to the biomarkers. Heart-to-brain weight ratios (HW:BrW) were correlated with NTproANP, NTproBNP, and cTnI concentrations in serum as well as fold change in expression of Nppa and Nppb. LVH was characterized by increased left ventricular wall thickness and inner diameter, increased cardiac output, decreased arterial blood pressure, and increased heart rate. In these studies, each end point contributed to the early detection of LVH, the ability to monitor its progression, and demonstrated the ability of NTproANP concentration in serum to predict LVH and hemodynamic changes.

Qualification of cardiac troponin I concentration in mouse serum using isoproterenol and implementation in pharmacology studies to accelerate drug development.

Cardiac troponin I is a useful biomarker of myocardial injury, but its use in mice and application to early drug discovery are not well described. The authors investigated the relationship between cTnI concentration in serum and histologic lesions in heart tissue from mice treated with isoproterenol (ISO). Cardiac TnI concentrations in serum increased in a dose-dependant manner and remained increased twenty-four to forty-eight hours after a single administration of isoproterenol. Increased cTnI concentration was of greater magnitude and longer duration than increased fatty acid binding protein 3 concentration, aspartate aminotransferase activity, and creatine kinase activity in serum. Isoproterenol-induced increases in cTnI concentrations were both greater and more sustained in BALB/c than in CD1 mice and correlated with incidence and severity of lesions observed in heart sections from both strains. In drug development studies in BALB/c mice with novel kinase inhibitors, cTnI concentration was a reliable stand-alone biomarker of cardiac injury and was used in combination with measurements of in vivo target inhibition to demonstrate an off-target contribution to cardiotoxicity. Additional attributes, including low cost and rapid turnaround time, made cTnI concentration in serum invaluable for detecting cardiotoxicity, exploring structure-activity relationships, and prioritizing development of compounds with improved safety profiles early in drug discovery.