Nonproliferative and Proliferative Lesions of the Rat and Mouse Skeletal Tissues (Bones, Joints, and Teeth).

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is an initiative of the Societies of Toxicological Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in the skeletal tissues and teeth of laboratory rats and mice, with color photomicrographs illustrating examples of many common lesions. The standardized nomenclature presented in this document is also available on the internet (http://www.goreni.org/). Sources of material were databases from government, academic and industrial laboratories throughout the world.

Regulatory forum opinion piece: Clarification and simplification of the pathology peer review documentation process.

The transparency and documentation of the peer review process have been discussed recently. Our position is that transparency is best achieved when peer review is a collaborative process, in which both parties are open-minded but both also realize that the study pathologist retains complete control over the findings (raw data) and over the content of the pathology report. For these reasons, we believe that histopathology raw data should be defined as the observations made by the study pathologist (printed and/or electronic formats) rather than as the tissue slides recommended by the Organisation for Economic Co-operation and Development (OECD). Also, because the study pathologist retains control over the histopathology raw data, any notes or tabulations of findings by the study pathologist and peer review pathologist during the peer review are interim notes and should not be included as an appendix to the pathology report though they may be retained if desired, as currently recommended. Because the histopathology raw data have not been created until completion of the peer review, the performance of a peer review should be documented in the study report, as currently recommended, but that it not be a GLP-compliant process.

Nasal turbinate enlargement due to cartilage and bone proliferation: a normal developmental finding in young ferrets.

Toxicity studies of intranasally administered, live attenuated influenza virus vaccine candidates conducted in male and female ferrets led to the microscopic observation of individual differences in the size of nasal turbinates, especially in the dorsal aspect of the nasal cavity. The association of these enlarged turbinates with acute to subacute inflammation, which is sometimes common in ferrets given live attenuated influenza virus vaccine candidates, led to this detailed microscopic evaluation of turbinate enlargement (cartilaginous and osseous thickening, or COT) in control animals dosed intranasally with saline. Results of this evaluation led to the conclusion that COT is a normal developmental feature of growing ferrets, irrespective of inflammation in nasal tissues or inflammatory exudate in the nasal cavity.

Effects of ICOS+ T cell depletion via afucosylated monoclonal antibody MEDI-570 on pregnant cynomolgus monkeys and the developing offspring.

MEDI-570 is a fully human afucosylated monoclonal antibody (MAb) against Inducible T-cell costimulator (ICOS), highly expressed on CD4+ T follicular helper (TFH) cells. Effects of MEDI-570 were evaluated in an enhanced pre-postnatal development toxicity (ePPND) study in cynomolgus monkeys. Administration to pregnant monkeys did not cause any abortifacient effects. Changes in hematology and peripheral blood T lymphocyte subsets in maternal animals and infants and the attenuated infant IgG immune response to keyhole limpet hemocyanin (KLH) were attributed to MEDI-570 pharmacology. Adverse findings included aggressive fibromatosis in one dam and two infant losses in the high dose group with anatomic pathology findings suggestive of atypical lymphoid hyperplasia. The margin of safety relative to the no observed adverse effect level (NOAEL) for the highest planned clinical dose in the Phase 1a study was 7. This study suggests that women of child bearing potential employ effective methods of contraception while being treated with MEDI-570.

Pharmacodynamic (phase 0) study using etaracizumab in advanced melanoma.

AlphaVbeta3 (alphavbeta3) is an important molecule for tumor-induced angiogenesis and is upregulated in metastatic melanoma (MM). We proposed to study the mechanism of action of etaracizumab, a monoclonal antibody targeting alphavbeta3, in MM. Patients with MM and biopsiable tumor were treated with etaracizumab in 3 dose cohorts starting from 8 mg/kg. Tumor saturation by etaracizumab using LM609 immunohistochemical staining of tumor sections was the primary endpoint. Subsequent dose cohorts were defined based on the tumor saturation by etaracizumab. Secondary end points were analysis of clinical benefit and changes from baseline of several tumor and peripheral blood biomarkers. Eighteen patients were enrolled at 3 dose levels. Etaracizumab showed better melanoma cell saturation at the 8mg/kg and 1 mg/kg dose compared with the 4 mg/kg dose and better vascular endothelial cell saturation at 8 mg/kg compared with lower dose groups. Etaracizumab demonstrated an acceptable safety profile. The optimal biologic dose out of those selected for investigation was 8 mg/kg. Patients treated at the highest dose may have had better clinical benefit secondary to suppression of the activated immediate downstream effector of alphavbeta3 signaling, FAK, in melanoma cells, but this alone did not ultimately affect melanoma cell proliferation or apoptosis. No apparent antiangiogenic or immunomodulatory effects of etaracizumab were noted.