BackgroundThe receptor kinase inhibitor toceranib phosphate (Palladia) was approved for use in dogs in 2009 using a dose of 3.25 mg/kg administered every other day. Preliminary data suggests that lower doses of toeceranib may be associated with a reduced adverse event profile while maintaining sufficient drug exposure to provide biologic activity. The purpose of this study was to determine the Cmax of toceranib in dogs with solid tumors receiving 2.5-2.75 mg/kg every other day and to document the adverse events associated with this dose rate. Secondary objectives included determination of plasma VEGF concentrations in treated dogs and response to therapy.ResultsDogs with solid tumors were administered toceranib at an intended target dose ranging from 2.5-2.75 mg/kg every other day and plasma samples were obtained for analysis of toceranib and VEGF plasma concentrations on days 0, 7, 14 and 30 of the study at 6 and 8 hours post drug administration. Additionally, plasma samples were obtained at 0, 1, 2, 6, 8, and 12 hours from dogs on day 30 for confirmation of Cmax. Response to therapy was assessed using standard RECIST criteria and adverse events were characterized using the VCOG-CTCAE. Toceranib administered at doses between 2.4-2.9 mg/kg every other day resulted in an average 6–8 hr plasma concentration ranging from 100–120 ng/ml, well above the 40 ng/ml concentration associated with target inhibition. Plasma VEGF concentrations increased significantly over the 30 day treatment period indicating that VEGFR2 inhibition was likely achieved in the majority of dogs. The lower doses of toceranib used in this study were associated with a substantially reduced adverse event profile compared to the established label dose of 3.25 mg/kg EOD.ConclusionsDoses of toceranib ranging from 2.4-2.9 mg/kg every other day provide drug exposure considered sufficient for target inhibition while resulting in an adverse event profile substantially reduced from that associated with the label dose of toceranib. This lower dose range of toceranib should be considered for future use in dogs with cancer.

Objectives Leishmaniosis is a vector-borne disease and in European countries is caused by Leishmania infantum. Cats are considered secondary reservoirs of the infection in endemic areas. The objective of this retrospective study is to describe the clinical findings, diagnosis, treatment and outcome of feline leishmaniosis (FeL) in 16 cats in Spain. Methods Medical records of cats diagnosed with leishmaniosis were retrospectively reviewed for cases that met the following inclusion criteria: identification of Leishmania organisms and/or DNA on cytological and/or histological specimens and/or a high anti- Leishmania antibody titre, compatible clinical findings and pathological abnormalities. Results Sixteen cats met the inclusion criteria, all of which were living in areas endemic for canine leishmaniosis. Systemic signs were present in 11 cases (68.8%). The most common clinical signs on presentation included cutaneous lesions in 12 cats (75%), ocular disease in six cats (37.5%) and anorexia in six cats (37.5%). A polyclonal gammopathy was noted in 12 cats (85.7%). Non-regenerative anaemia and renal abnormalities were present in six (37.5%) and five patients (31.3%), respectively. In nine cats (56.3%), immunosuppressive conditions/comorbidities were identified. The diagnosis was made in eight of the cats (50%) by cytology, but a combination of diagnostic tests was needed for definitive diagnosis in the remaining patients. Twelve cats (75%) were treated specifically for leishmaniosis. Five of the 12 cats (41.7%) did not improve with treatment. The median survival time in the group of patients treated specifically for leishmaniosis was 17 months. Median survival of patients treated with concomitant diseases was 13 months vs 41 months in those without, although this was not statistically significant ( P = 0.557). Conclusions and relevance Presentation of FeL appears to be similar to canine leishmaniosis but with some specific features: ulcerative and nodular skin lesions are the predominant cutaneous signs; cats with immunosuppressive conditions or co-existing diseases were more commonly present than typically seen in dogs (mainly feline immunodeficiency virus). A combination of diagnostic tests may be needed for definitive diagnosis.

BackgroundThe purpose of this study was to evaluate the activity of Selective Inhibitors of Nuclear Export (SINE) compounds that inhibit the function of the nuclear export protein Exportin 1 (XPO1/CRM1) against canine tumor cell lines and perform a Phase I clinical trial of KPT-335 in dogs with spontaneous cancer to provide a preliminary assessment of biologic activity and tolerability.Methods and FindingsCanine tumor cell lines derived from non-Hodgkin lymphoma (NHL), mast cell tumor, melanoma and osteosarcoma exhibited growth inhibition and apoptosis in response to nanomolar concentrations of SINE compounds; NHL cells were particularly sensitive with IC50 concentrations ranging from 2–42 nM. A Phase I clinical trial of KPT-335 was performed in 17 dogs with NHL (naive or relapsed), mast cell tumor or osteosarcoma. The maximum tolerated dose was 1.75 mg/kg given orally twice/week (Monday/Thursday) although biologic activity was observed at 1 mg/kg. Clinical benefit (CB) including partial response to therapy (PR, n = 2) and stable disease (SD, n = 7) was observed in 9/14 dogs with NHL with a median time to progression (TTP) for responders of 66 days (range 35–256 days). A dose expansion study was performed in 6 dogs with NHL given 1.5 mg/kg KPT-335 Monday/Wednesday/Friday; CB was observed in 4/6 dogs with a median TTP for responders of 83 days (range 35–354 days). Toxicities were primarily gastrointestinal consisting of anorexia, weight loss, vomiting and diarrhea and were manageable with supportive care, dose modulation and administration of low dose prednisone; hepatotoxicity, anorexia and weight loss were the dose limiting toxicities.ConclusionsThis study provides evidence that the novel orally bioavailable XPO1 inhibitor KPT-335 is safe and exhibits activity in a relevant, spontaneous large animal model of cancer. Data from this study provides critical new information that lays the groundwork for evaluation of SINE compounds in human cancer.

Objectives To assess the utility of urine dipstick strips for detection of feline proteinuria when used in combination with urine‐specific gravity, compared with urine protein‐to‐creatinine ratio as the gold standard. Materials and Methods Retrospective analysis of clinical records of comprehensive urine examination obtained from cats presented to a referral hospital. Diagnostic agreement and test accuracy were calculated for the dipstick test alone and in combination with the urine‐specific gravity, using different cut‐off values for proteinuria. Receiver‐operating characteristic curves were also calculated. Results A total of 121 urine samples were included. The diagnostic agreement between dipstick and urine protein‐creatinine ratio was poor. A dipstick result of equal or greater than “Trace” (0.1–0.3 g/L) had a sensitivity of 81% and a specificity of 31% to detect proteinuria. Grouping the samples by urine‐specific gravity did not increase dipstick agreement with the urine protein‐creatinine ratio and only resulted in a slight improvement in the accuracy of detecting proteinuria. Clinical Significance The dipstick test was not accurate for detecting proteinuria when combined with urine‐specific gravity in cats. Clinicians should not rely on this test and, regardless of the urine concentration, other appropriate quantitative methods such as urine protein‐creatinine ratio should always be performed to detect proteinuria in cats.

SINE (Selective Inhibitors of Nuclear Export) block the activity of XPO1/CRM1, 1 of 7 nuclear export proteins in cells, forcing the nuclear retention of key tumor suppressor proteins, leading to selective apoptosis of tumor cells. The purpose of these studies was to evaluate the in vitro activity of SINE against canine tumor cell lines and investigate the biological activity of verdinexor (KPT-335) in dogs with spontaneous cancers as proof of principle for human clinical studies. Several different canine tumor cell lines including those derived from non-Hodgkin Lymphoma (NHL) exhibited growth inhibition and apoptosis in response to nanomolar concentrations of SINE; NHL cells were particularly sensitive with IC50 2-42 nM. A Phase I clinical trial of verdinexor was performed in dogs with cancer with an emphasis on NHL given in vitro activity demonstrated against the tumor cell lines. The MTD was 1.75 mg/kg twice per week although biological activity was observed at 1 mg/kg. Clinical benefit including Partial Response (PR) and Stable Disease (SD) for at least 4 weeks was observed in 9/14 dogs with NHL with a median time to progression of 66 days (range 35-256). A dose expansion study was performed in 6 dogs with NHL given 1.5 mg/kg verdinexor on a Monday/Wednesday/Friday (MWF) regimen; clinical benefit (PR+SD) was observed in 4/6 dogs with a median time to progression of 83 days (range 35-354). Toxicities were primarily gastrointestinal consisting of anorexia, weight loss, vomiting and diarrhea and were manageable with supportive care and dose modulation. A validated health related Quality of Life (QOL) form used to assess dogs during treatment demonstrated that the overall quality of life did not decrease in dogs in this study supporting the notion that clinical toxicities associated with verdinexor are generally well tolerated. Based on these findings, a Phase IIb study was performed in 58 dogs with either newly diagnosed or relapsed NHL. Drug was administered initially at 1.5 mg/kg MWF, but this dosing regimen was changed to 1.25 mg/kg M/Th due to the high rate of anorexia and weight loss on the MWF regimen; dose escalation was permitted to 1.5 mg/kg on the M/Th regimen.. The objective response rate was 29% (1 CR, 16 PR) with an additional 25 dogs experiencing SD for a minimum of 4 weeks, resulting in a of 72% disease control rate. While the median time to progression was approximately 6 weeks, 19 dogs (32%) remained on study drug for more than 8 weeks. Laboratory abnormalities were minimal. Together, these data provide robust evidence that the novel orally bioavailable XPO1 inhibitor vrdinexor exhibits single agent biological activity in a spontaneous large animal model of human NHL. Furthermore, verdinexor was well tolerated even in the absence of supportive care, suggesting that SINE compounds could exhibit good long-term tolerability in people. Citation Format: Cheryl A. London, Luis Feo Bernabe, Sandra Barnard, William Kisseberth, Antonella Borgatti, Michael Henson, Heather Wilson-Robles, Kiersten Jensen, Daisuke Ito, Jaime Modiano, Misty Bear, Michael Pennell, Jean-Richard Saint-Martin, Dilara McCauley, Michael Kauffman, Sharon Shacham. Evaluation of the novel, orally bioavailable selective inhibitor of nuclear export (SINE) KPT-335 (verdinexor) in spontaneous canine cancer: Results of phase I and phase II clinical trials. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3809. doi:10.1158/1538-7445.AM2014-3809