Guide for Combining Primary Tumors for Statistical Analysis in Rodent Carcinogenicity Studies

The Tumor Combination Guide was created at the request of the U. S. Food and Drug Administration (FDA) by a Working Group of biopharmaceutical experts from international societies of toxicologic pathology, the Food and Drug Administration (FDA), and members of the Standard for Exchange of Nonclinical Data (SEND) initiative, to assist pharmacology/toxicology reviewers and biostatisticians in statistical analysis of nonclinical tumor data. The guide will also be useful to study and peer review pathologists in interpreting the tumor data. This guide provides a higher-level hierarchy of tumor types or categories correlating the tumor names from the International Harmonization of Nomenclature and Diagnostic Criteria (INHAND) publications with those available in the NEOPLASM controlled terminology (CT) code list in SEND. The version of CT used in a study should be referenced in the nonclinical study data reviewer's guide (SDRG) (section 3.1) of electronic submissions to the FDA. The tumor combination guide instructions and examples are in a tabular format to make informed decisions for combining tumor data for statistical analysis. The strategy for combining tumor types for statistical analysis is based on scientific criteria gleaned from the current scientific literature; as SEND and INHAND terminology and information evolve, this guide will be updated.

Combination of two novel blocking antibodies, anti-PD-1 antibody ezabenlimab (BI 754091) and anti-LAG-3 antibody BI 754111, leads to increased immune cell responses

Upregulation of inhibitory receptors, such as lymphocyte activation gene-3 (LAG-3), may limit the antitumor activity of therapeutic antibodies targeting the programmed cell death protein-1 (PD-1) pathway. We describe the binding properties of ezabenlimab, an anti-human PD-1 antibody, and BI 754111, an anti-human LAG-3 antibody, and assess their activity alone and in combination. Ezabenlimab bound with high affinity to human PD-1 (K_D = 6 nM) and blocked the interaction of PD-1 with PD-L1 and PD-L2. Ezabenlimab dose-dependently increased interferon-γ secretion in human T cells expressing PD-1 in co-culture with PD-L1-expressing dendritic cells. Administration of ezabenlimab to human PD-1 knock-in mice dose-dependently inhibited growth of MC38 tumors. To reduce immunogenicity, ezabenlimab was reformatted from a human IgG4 to a chimeric variant with a mouse IgG1 backbone (BI 905725) for further in vivo studies. Combining BI 905725 with anti-mouse LAG-3 antibodies improved antitumor activity versus BI 905725 monotherapy in the MC38 tumor model. We generated BI 754111, which bound with high affinity to human LAG-3 and prevented LAG-3 interaction with its ligand, major histocompatibility complex class II. In an in vitro model of antigen-experienced memory T cells expressing PD-1 and LAG-3, interferon-γ secretion increased by an average 1.8-fold versus isotype control (p = 0.027) with BI 754111 monotherapy, 6.9-fold (p < 0.0001) with ezabenlimab monotherapy and 13.2-fold (p < 0.0001) with BI 754111 plus ezabenlimab. Overall, ezabenlimab and BI 754111 bound to their respective targets with high affinity and prevented ligand binding. Combining ezabenlimab with BI 754111 enhanced in vitro activity versus monotherapy, supporting clinical investigation of this combination (NCT03156114; NCT03433898).

Scientific and Regulatory Policy Committee Best Practices: Documentation of Sexual Maturity by Microscopic Evaluation in Nonclinical Safety Studies

The sexual maturity status of animals in nonclinical safety studies can have a significant impact on the microscopic assessment of the reproductive system, the interpretation of potential test article-related findings, and ultimately the assessment of potential risk to humans. However, the assessment and documentation of sexual maturity for animals in nonclinical safety studies is not conducted in a consistent manner across the pharmaceutical and chemical industries. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology convened an international working group of pathologists and nonclinical safety scientists with expertise in the reproductive system, pathology nomenclature, and Standard for Exchange of Nonclinical Data requirements. This article describes the best practices for documentation of the light microscopic assessment of sexual maturity in males and females for both rodent and nonrodent nonclinical safety studies. In addition, a review of the microscopic features of the immature, peripubertal, and mature male and female reproductive system and general considerations for study types and reporting are provided to aid the study pathologist tasked with documentation of sexual maturity.

Abstract 4547: Characterization of the LAG-3 targeting antibody BI 754111 in monotherapy and in combination with the anti-PD-1 antibody BI 754091

Lymphocyte activation gene-3 (LAG-3) is an inhibitory receptor involved in maintaining immunological tolerance via regulation of T-cell activation, proliferation and response. Ligand-mediated activation of LAG-3 negatively regulates T-cell activity that is thought to actively contribute to tumor immune evasion beyond the established programmed cell death-1 (PD-1) pathway.

BI 754111, a humanized IgG4 monoclonal antibody (mAb) with high affinity against LAG-3, blocks the interaction between LAG-3 and MHC II. BI 754111 was characterized in a panel of binding, blocking and functional cell-based assays; safety assessment was done in cynomolgus monkeys. BI 754111 is not mouse cross-reactive; therefore a surrogate mLAG-3 antibody was used for in vivo mouse efficacy studies. The ability of BI 754111 to stimulate cytokine production by exhausted human T cells in vitro was tested in an autologous assay system with antigen specific memory T cells being re-stimulated by antigen-pulsed dendritic cells in the presence of increasing amounts of BI 754111 or BI 754091 (anti-hPD-1 mAb) or a combination of increasing amounts of BI 754111 and a saturating dose of BI 754091. Under these assay conditions the majority of T cells co-expressed the exhaustion markers PD-1 and LAG-3 on the surface. At the end of the experiment supernatants were harvested and analyzed for IFNγ secretion as a measure of T-cell activation. Monotherapy of BI 754111 moderately increased IFNγ secretion (average of 1.8 fold) compared to BI 754091 monotherapy (6.9-fold average increase). Combining BI 754111 with BI 754091 was synergistic and led to a 13.2-fold increase in IFNγ secretion.

MC-38 tumor-bearing mice (C57BL/6NTac-PDCD1tm(PDCD1)Arte mice expressing parts of the human instead of the murine extracellular domain of PD-1) were used to determine the in vivo activity of the anti-LAG3 and anti-PD-1 combination. A mouse tool antibody against mLAG-3 (IgG1 D265A) and BI 905725 (a mouse IgG1 D265A version of BI 754091, anti-hPD-1 mAb) were tested at a dose of 10 mg/kg in a q3or4d schedule as monotherapy or in combination. No anti-tumor activity was observed under mLAG-3 mAb treatment, whereas treatment with anti-PD-1 resulted in a median TGI of 100% and 4 out of 10 tumors showed a complete response. The combination of anti-PD-1 and anti-LAG-3 resulted in a median TGI of 103% and doubled the number of complete responses (8/10).

BI 754111 binds to cynomolgus monkey LAG-3 with comparable affinity as to hLAG-3 thus allowing pharmacokinetic and toxicological assessment in this species. Repeated high doses of BI 754111 were well tolerated without adverse immune-related side effects.

The above results describe synergistic effects upon combination of PD-1 and LAG-3 treatment thus supporting the ongoing clinical trial in which BI 754111 is being tested in combination with BI 754091 (NCT03156114).

Citation Format: Markus Zettl, Melanie Wurm, Otmar Schaaf, Iñigo Tirapu, Sven Mostböck, Markus Reschke, Stephan-Michael Schmidbauer, Lee Frego, Ivo C. Lorenz, Michael Thibodeau, Diann Blanset, Elisa Oquendo Cifuentes, Jürgen Moll, Norbert Kraut, Eric Borges, Anne Vogt, Jonathon Sedgwick, Irene C. Waizenegger. Characterization of the LAG-3 targeting antibody BI 754111 in monotherapy and in combination with the anti-PD-1 antibody BI 754091 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4547.

Abstract 4558: In vitro and in vivo characterization of the PD-1 targeting antibody BI 754091

The programmed cell death-1 (PD-1) receptor provides inhibitory checkpoint signals to activated T cells upon binding to its ligands, PD-L1 and PD-L2, which are expressed on antigen-presenting cells and cancer cells leading to suppression of T-cell effector function and tumor immune evasion. Blockade of the PD-1 axis using either anti-PD-1 or anti-PD-L1 approved monoclonal antibodies (mAbs) results in improved T-cell effector function and anti-tumor immune responses. Durable tumor responses occur in 15-30% of cancer patients.

BI 754091, a humanized IgG4 mAb with high affinity against hPD-1 blocks the interaction between PD-1 and PD-L1 or PD-L2. BI 754091 was characterized in a panel of binding, blocking and functional cell-based assays. In addition, efficacy and safety was assessed in mice and in cynomolgus monkeys, respectively. The ability of BI 754091 to stimulate cytokine production in exhausted human T cells in vitro was tested in an autologous assay system with antigen-specific memory CD4+ T cells being re-stimulated by antigen-pulsed dendritic cells in the presence of BI 754091 or isotype control. Under these assay conditions the majority of T cells co-expressed the exhaustion markers PD-1 and LAG-3 on their surface. Furthermore, PD-L1 and PD-L2 were expressed on the dendritic cells. At the end of the experiment supernatants were harvested and analyzed for IFNγ secretion as a measure for T-cell activation. BI 754091 showed a potent dose dependent T-cell activation. The average fold increase of IFNγ was 7.9 as compared to isotype control, with an average EC50 of 0.9 nM.

The in vivo activity of BI 754091 was determined in MC-38 tumor-bearing mice, using a mouse strain where parts of the extracellular domain of murine PD-1 was replaced by the corresponding human PD-1 domain (C57BL/6NTac-PDCD1tm(PDCD1)Arte mice). A dose of 10 mg/kg BI 754091, given either as single treatment or in a twice weekly schedule, induced significant tumor growth inhibition (median TGI of 83% and 90%, respectively) and complete responses (CRs) in some tumors (3 CRs out of 10 and 2 CRs out of 10, respectively).

BI 754091 binds to PD-1 from cynomolgus monkeys with comparable affinities as to human PD-1, thus allowing pharmacokinetic and toxicological assessment in this species. Repeated high doses of BI 754091 were well tolerated without adverse immune-related effects.

BI 754091 is currently undergoing clinical investigations (NCT02952248).

Citation Format: Markus Zettl, Melanie Wurm, Otmar Schaaf, Iñigo Tirapu, Sven Mostböck, Markus Reschke, Stephan-Michael Schmidbauer, Lee Frego, Ivo C. Lorenz, Michael Thibodeau, Diann Blanset, Elisa Oquendo Cifuentes, Jürgen Moll, Norbert Kraut, Eric Borges, Anne Vogt, Jonathon Sedgwick, Irene C. Waizenegger. In vitro and in vivo characterization of the PD-1 targeting antibody BI 754091 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4558.

Photocatalytic properties of nanocrystalline titanium dioxide films in the degradation of domoic acid in aqueous solution: potential for use in molluscan shellfish biotoxin depuration facilities

Domoic acid (DA) is a water-soluble marine neurotoxin produced and released by certain species of the diatom genus Pseudo-nitzschia. Present in coastal waters, it can be a threat to public health and marine life, and can result in severe economic losses to the molluscan shellfish and crustacean harvesting industries. Here we report on the efficiency of nanocrystalline (NC) titania (TiO(2)) thin films used as a photocatalyst in the ultraviolet light photodegradation of DA. Titanium dioxide thin films produced by a sol-gel dip-coating method in the presence of polyethylene glycol of different molecular weights (200, 400 and 600) were deposited on glass substrates and crystallised at 90 degrees C. The films were characterised using spectroscopic ellipsometry, Fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. The photocatalytic activity measurements were carried out by immersing the NC TiO(2) films in a DA solution (2500 ng ml(-1)) and then exposing them for various times at room temperature to UVA irradiation (lambda = approximately 350 nm). The degradation of DA, quantified by HPLC analysis, was not significant when using daylight or ultraviolet light irradiation alone, whereas the NC TiO(2) films prepared at low temperature proved to be a very efficient photocatalyst when used in conjunction with UVA light. The effectiveness of the photodegradation was improved by increasing molecular weight of polyethylene glycol, which increased the thickness of the film. The presence, transformation and degradation of three DA isomers were observed. The approach may eventually be practical for destroying DA in seawater used by aquaculture industry depuration facilities.

Experimental autoimmune encephalomyelitis induction in peptidylarginine deiminase 2 knockout mice

During the development of multiple sclerosis the destruction of the myelin sheath surrounding the neurites is accompanied by citrullination of several central nervous system (CNS) proteins, including myelin basic protein and glial fibrillary acidic protein. In experimental autoimmune encephalomyelitis (EAE), a disease induced in animals by immunization with proteins or peptides from the CNS, the animals develop symptoms similar to multiple sclerosis (MS). The increased levels of citrullinated CNS proteins associated with MS are also observed during the development of EAE. To study the role of CNS protein citrullination in EAE development, we induced EAE with a peptide derived from myelin oligodendrocyte glycoprotein (MOG(35-55)) in mice lacking the peptidylarginine deiminase 2 (PAD2) protein, because this enzyme was the most likely candidate to be involved in catalyzing CNS protein citrullination in the diseased state. Even though the PAD2 knockout mice displayed a dramatic reduction in the amount of citrullination present in the CNS, indicating that PAD2 is indeed responsible for the majority of detectable citrullination observed in EAE, the development of EAE was not impaired by genetic deletion of PAD2, suggesting that PAD2 catalyzed citrullination is not essential to the development of EAE.

Silica-induced caspase activation in mouse alveolar macrophages is dependent upon mitochondrial integrity and aspartic proteolysis

Although silica has been documented to cause apoptotic cell death, the cellular pathways leading to caspase activation have not been extensively investigated. Here we demonstrate in a mouse macrophage cell line (MH-S cells) that alpha-quartz silica exposure (12.5 mug/cm2 to 50 mug/cm2) elicited activation of both caspase 3 and caspase 9, whereas anatase titanium dioxide (TiO2), a non-fibrogenic particle, did not. Silica exposure in vitro also induced apoptosis after 6 h, as measured by the appearance of subdiploid cell fragments in a flow cytometric analysis. Exposure to TiO 2 did not elicit significant apoptosis. Silica-induced apoptosis and caspase 3 activation were, in part, caspase 9 dependent, as determined by their sensitivity to either a general caspase inhibitor (Z-VAD-FMK) or a specific caspase 9 inhibitor (Z-LEHD-FMK). Silica exposure in vitro also elicited significant mitochondrial depolarization after 2 and 6 h of exposure. Cyclosporin A, an inhibitor of the mitochondrial permeability pore, partially decreased mitochondrial depolarization, caspase 3 activation, and caspase 9 activation, suggesting a role for mitochondrial dysfunction in these events. Pepstatin A, an inhibitor of cathepsin D, also decreased mitochondrial depolarization, caspase 3 activation, and caspase 9 activation, whereas leupeptin, an inhibitor of cathepsin B, had no effect. These data suggest that short-term silica exposure in vitro induces both caspase 3 and caspase 9 activity, which appears to participate in apoptosis. Activation of these caspases seems to be dependent, in part, on aspartic proteolysis and loss of mitochondrial integrity.

p53 and its co-activator p300 are inversely regulated in the mouse colon in response to carcinogen

We examined the p53 response following acute exposure of mice to the colon-specific carcinogen azoxymethane (AOM). No overall induction of p53-regulated genes was observed in the mouse colon, and only a small subpopulation of apoptotic colonocytes showed increased Bax staining. In contrast, the liver showed dramatic increases in p53-regulated gene expression. Subdued p53 gene activation in the colon did not appear to result from a lack of p53 stabilization, but did correspond to a drop in the expression of its transcriptional co-activator, p300. We propose that inefficient gene activation by p53 in the colon contributes to the organotrophic effects of AOM.

Effect of nitrogen dioxide on ovalbumin-induced allergic airway disease in a murine model

The effect of exposure to irritant air pollutants on the development of allergic airway disease is poorly understood. This study examines the effects of the lower respiratory tract irritant, NO(2), on the outcome of ovalbumin (OVA)-induced allergic airway disease. Male and female C57Bl/6 mice were sensitized by weekly intraperitoneal (ip) OVA injections for 3 wk followed by daily 1-h OVA aerosol inhalation challenge for 3 or 10 d. Initially, mice were exposed daily for 3 d to air or 0.7 or 5 ppm NO(2) for 2 h following each OVA aerosol challenge. OVA exposure resulted in pronounced lower airway inflammation, as evidenced by a significant increase in bronchoalveolar lavage (BAL) total cellularity and eosinophil levels. BAL eosinophil levels were significantly lower in OVA-NO(2) compared to OVA-air animals. The reduction was similar at both NO(2) exposure concentrations. In a subsequent study, sensitized animals were exposed for 3 or 10 d to aerosolized OVA followed by air or 0.7 ppm NO(2). BAL eosinophils were again reduced at 3 d by OVA-NO(2) exposure compared to OVA-air mice. At 10 d the eosinophilia was virtually abolished. This reduction in OVA-induced cellular inflammation by NO(2) was confirmed by histopathological analysis. Contrary to expectations, exposure to NO(2) during the aerosol challenge to OVA dramatically diminished the outcome of allergic disease in lungs as measured by airway cellular inflammation.

Cellular and molecular mechanisms regulating silica-induced adhesion molecule expression in mice

Exposure of mice to silica particles generates an intense inflammatory response characterized by the influx of neutrophils and monocytes into the alveoli with resulting cell activation. These cell trafficking and effector functions are, in part, mediated by different families of adhesion molecules. One such adhesion protein, intercellular adhesion molecule-1 (ICAM-1), is expressed on a variety of cells including vascular endothelial cells, fibroblasts, types I and II alveolar epithelial cells, some lymphocytes, and monocytes/macrophages. Over the last several years, our laboratory has focused on silica-induced ICAM-1 expression in exposed mice (in vivo) and cells (in vitro) by examining the role and regulation of this adhesion protein on pulmonary cells. We have determined that intratracheal exposure of mice to silica (2 mg per mouse) elicits increased expression of ICAM-1 on pulmonary macrophages and type II epithelial cells within the lung parenchyma, on bronchoalveolar lavage macrophages, and as a soluble protein in lavage fluid. We hypothesize that increased ICAM-1 expression mayparticipate in silica-induced neutrophil influx into the alveoli, as well as in macrophage-derived phlogistic signals responsible for migration of neutrophils. ICAM-1 expression on silica-exposed mouse macrophages is enhanced by reactive oxygen species (ROS) and tumor necrosis factor-alpha (TNF-alpha) and appears to be regulated through specific sequence elements within the ICAM-1 promoter.

Expectant treatment of ectopic pregnancies: clinical and sonographic predictors

OBJECTIVE

We identified the potential clinical and sonographic predictors of the spontaneous resolution of ectopic pregnancies.

SUBJECTS AND METHODS

We performed a prospective study of 78 consecutive patients with a transvaginal sonographic diagnosis of ectopic pregnancy who had either two consecutive quantitative measurements of their beta subunit of human chorionic gonadotropin (beta-hCG) more than 24 hrs apart or an embryo with a heart beat. We evaluated the patient's age, time from the last menstrual period, beta-hCG level, size of ectopic pregnancy, presence of a gestational sac or embryonic elements, vascularity on color Doppler sonography, peak systolic velocity, and resistive index of ectopic pregnancy at the time of presentation as potential independent predictors of the final outcome. Logistic regression was performed to identify the independent predictors.

RESULTS

Forty-six patients had declining beta-hCG levels, and 32 ectopic pregnancies showed an embryo with a heart beat or had steady or rising beta-hCG levels. Univariate analysis indicated that a longer time from the last menstrual period (older ectopic pregnancies), lower beta-hCG levels, and the absence of gestational sac are statistically more significantly seen in ectopic pregnancies with declining beta-hCG levels (p < 0.05). Resistive index of ectopic pregnancy reached borderline significance (p = 0.05). In a multiple logistic model, the same variables were independent predictors of outcome (p < 0.05). Resistive index was also a predictor (p = 0.09).

CONCLUSION

Longer times from the last menstrual period, lower beta-hCG levels, absence of gestational sacs, and higher resistive indexes of ectopic pregnancy at the time of presentation appear to be independent predictors of the spontaneous resolution of ectopic pregnancy.

Sonographic appearance of benign and malignant conditions of the colon

OBJECTIVE

The objective of this study was to compare the sonographic appearance of different abnormalities of the colon to evaluate the role of sonography in their differential diagnosis.

MATERIALS AND METHODS

We retrospectively reviewed videotaped sonographic examinations of 99 patients with proven diagnoses that included diverticulitis (n = 35), malignancy (n = 20), Crohn's disease (n = 16), pseudomembranous colitis (n = 14), ischemic colitis (n = 9), and ulcerative colitis (n = 5). Data were collected with regard to gut features, including the site of colonic involvement, associated small-bowel involvement, length of diseased segment, stratification, luminal contents, pneumatosis, and diverticula. Perigut features evaluated included abnormal fat, abscess, fistula, and ascites.

RESULTS

On sonography, the following features were statistically significant (p < .05). Involvement of the small bowel was more common in patients with Crohn's disease than in the remainder of the study population (44% versus 1%). Left-sided colonic disease (91% versus 38%), diverticula (91% versus 3%), and perigut findings (91% versus 57%), including abnormal fat (83% versus 39%) and abscess (34% versus 8%), were features that indicated diverticulitis. Malignant conditions were more common in patients with a greater wall thickness (mean, 26.2 mm versus 10.2 mm), asymmetric involvement (85% versus 39%), loss of stratification (85% versus 20%), absence of perigut findings (65% versus 22%), and involvement of a short diseased segment (70% versus 16%). Involvement of the entire colon (50% versus 2%), luminal contents (64% versus 28%), and ascites (64% versus 26%) were features suggesting pseudomembranous colitis.

CONCLUSION

Although the sonographic appearances of abnormalities of the colon overlap, some sonographic features are helpful in the differential diagnosis of colonic abnormalities.

Role of endovaginal sonography in the diagnosis and management of ectopic pregnancy

Although diagnostic laparoscopy is still considered the standard reference in the diagnosis of ectopic pregnancy (EP), use of high-resolution endovaginal sonography, in conjunction with qualitative serum assays of the beta subunit of human chorionic gonadotropin (beta-hCG), allows detection of earlier and smaller EPs. The most common endovaginal sonographic finding of EP (89%-100% of cases) is an extraovarian, round or elongated, solid tubal mass. A tubal ring (an extrauterine saclike structure) is the second most common finding (40%-68% of cases). Pelvic fluid may be present, but it is a nonspecific finding. An EP may have a pseudosac, which can be distinguished sonographically from the true gestational sac of an intrauterine pregnancy. Color Doppler techniques can complement endovaginal sonographic findings, but they should be performed only after a thorough real-time evaluation of the adnexal region. Current therapeutic options for EP include expectant management (ie, close follow-up), medical treatment (usually injections of methotrexate), and surgery. Accurate diagnosis with endovaginal sonography is the prerequisite to nonsurgical management, since surgery is the logical treatment if laparoscopy is used for diagnosis.

Sonographic diagnosis of isolated gallbladder trauma

We report a patient with isolated post-traumatic injury to the gallbladder diagnosed preoperatively by ultrasonography. Demonstration of echogenic, nonshadowing, mobile material in the gallbladder should suggest this diagnosis. Early diagnosis is essential because, unlike other abdominal organ injuries which may be managed conservatively, injury to the gallbladder requires surgery.

Acute epidural hematoma following decompressive surgery of a subdural hematoma

We report a patient with acute epidural hematoma diagnosed using computed tomography shortly after decompressive surgery of a contralateral subdural hematoma not resulting in clinical evidence of improvement. The patient underwent successful second emergency decompressive surgery. Prompt recognition is essential for a successful outcome, and poor recovery, when not otherwise anticipated, should alert immediately to a possible contralateral hematoma.