Alfred M. Legendre

Masitinib is safe and effective for the treatment of canine mast cell tumors.

BACKGROUND Activation of the KIT receptor tyrosine kinase is associated with the development of canine mast cell tumors (MCT). HYPOTHESIS/OBJECTIVE To evaluate the efficacy of masitinib, a potent and selective inhibitor of KIT, in the treatment of canine MCT. ANIMALS Two hundred and two client-owned dogs with nonmetastatic recurrent or nonresectable grade II or III MCT. METHODS Double-blind, randomized, placebo-controlled phase III clinical trial. Dogs were administered masitinib (12.5 mg/kg/d PO) or a placebo. Time-to-tumor progression (TTP), overall survival, objective response at 6 months, and toxicity were assessed. RESULTS Masitinib increased overall TTP compared with placebo from 75 to 118 days (P = .038). This effect was more pronounced when masitinib was used as first-line therapy, with an increase in the median TTP from 75 to 253 days (P = .001) and regardless of whether the tumors expressed mutant (83 versus not reached [P = .009]) or wild-type KIT (66 versus 253 [P = .008]). Masitinib was generally well tolerated, with mild (grade I) or moderate (grade II) diarrhea or vomiting as the most common adverse events. CONCLUSIONS AND CLINICAL IMPORTANCE Masitinib is safe and effective at delaying tumor progression in dogs presenting with recurrent or nonresectable grade II or III nonmetastatic MCT.

Prevalence of infectious diseases in feral cats in Northern Florida.

Objectives of this study were to determine prevalence of infection in feral cats in Northern Florida with a select group of infectious organisms and to determine risk factors for infection. Blood samples or sera from 553 cats were tested with a panel of antibody, antigen or PCR assays. Male cats were at higher risk for FIV, Mycoplasma haemofelis, and M. haemominutum. Infection with either FeLV or FIV was associated with increased risk for coinfection with the other retrovirus, M. haemofelis, or M. haemominutum. Bartonella henselae had the highest prevalence and was the only organism that did not have any associated risk for coinfection with other organisms. Feral cats in this study had similar or lower prevalence rates of infections than those published for pet cats in the United States. Thus, feral cats assessed in this study appear to be of no greater risk to human beings or other cats than pet cats.

Antigen and antibody testing for the diagnosis of blastomycosis in dogs.

BACKGROUND Early diagnosis and treatment are associated with an improved prognosis in blastomycosis. The diagnosis of blastomycosis may be missed by cytology, histopathology, culture, or serology. An enzyme immunoassay (EIA) for detection of Blastomyces dermatitidis galactomannan antigen in body fluids has been used for rapid diagnosis of blastomycosis in humans. HYPOTHESIS Measurement of Blastomyces antigen in urine or serum by the MVista Blastomyces antigen EIA is more sensitive than measurement of anti-Blastomyces antibodies for diagnosis of blastomycosis in dogs. METHODS Serum and urine samples from 46 dogs with confirmed blastomycosis were tested for Blastomyces antigen and serum was tested for anti-Blastomyces antibodies. RESULTS The sensitivity for the detection of antigen in urine was 93.5% and it was 87.0% in serum. The sensitivity of antibody detection by agar gel immunodiffusion (AGID) was 17.4% and it was 76.1% by EIA. Antigen and antibody decreased during itraconazole treatment. CONCLUSIONS AND CLINICAL IMPORTANCE Antigen detection is a more sensitive test for diagnosis of blastomycosis than antibody testing by AGID, the only commercially available method. Antigen concentrations decreased with treatment.

Evaluation of 12- and 24-month survival rates after treatment with masitinib in dogs with nonresectable mast cell tumors.

OBJECTIVE To evaluate the effectiveness of masitinib for the treatment of nonresectable mast cell tumors (MCTs) in dogs at 12 and 24 months after onset of treatment. ANIMALS 132 dogs with nonresectable grade 2 or 3 MCTs. PROCEDURES Dogs received masitinib (12.5 mg/kg/d, PO; n = 106) or a placebo (26). After 6 months, treatment was extended with tumor assessments at 3-month intervals until detection of disease progression. Endpoints were tumor response and overall survival rate and time. RESULTS In dogs with nonresectable MCTs, masitinib significantly improved survival rate, compared with results for the placebo, with 59 of 95 (62.1%) and 9 of 25 (36.0%) dogs alive at 12 months and 33 of 83 (39.8%) and 3 of 20 (15.0%) dogs alive at 24 months, respectively. Median overall survival time was 617 and 322 days, respectively. Tumor control at 6 months had a high predictive value for 24-month survival, with high specificity (88%) and sensitivity (76%), whereas short-term tumor response (within 6 weeks) had a poor predictive value. Complete responses at 24 months were observed in 6 of 67 (9.0%) dogs with nonresectable MCTs treated with masitinib. CONCLUSIONS AND CLINICAL RELEVANCE Masitinib significantly increased survival rates at 12 and 24 months in dogs with nonresectable MCTs. Control of disease at 6 months, but not best response at 6 weeks, was predictive of long-term survival in dogs treated with masitinib, which suggested that short-term response may be irrelevant for assessing clinical efficacy of tyrosine kinase inhibitors for treatment of MCTs.

Nested PCR Assays for Detection of Blastomyces dermatitidis DNA in Paraffin-Embedded Canine Tissue

ABSTRACT A Blastomyces dermatitidis nested PCR assay targeting the gene encoding the Wisconsin 1 (WI-1) adhesin was developed and compared with a nested PCR targeting the 18S rRNA gene (rDNA) of members of the family Onygenaceae. We examined 73 paraffin-embedded tissue samples obtained from nine dogs which died of blastomycosis and nine dogs which succumbed to lymphosarcoma according to autopsy findings; amplifiable canine DNA was extracted from 25 and 33 specimens from the two groups, respectively. The B. dermatitidis PCR amplified DNA from 8 of 13 tissue samples in which yeast cells were detected by microscopy. Sequencing revealed that all PCR products were homologous to the B. dermatitidis WI-1 adhesin gene. No PCR product was amplified from 12 microscopically negative biopsy specimens from dogs with blastomycosis or from 33 biopsy specimens from dogs with lymphosarcoma. The 18S rDNA PCR amplified DNA from 10 and 9 tissue samples taken from dogs which died of blastomycosis and lymphosarcoma, respectively. Only six products were identified as being identical to B. dermatitidis 18S rDNA; they were exclusively obtained from specimens positive by the B. dermatitidis nested PCR. For specificity testing, 20 human biopsy specimens proven to have histoplasmosis were examined, and a specific H. capsulatum product was amplified by the 18S rDNA PCR from all specimens, whereas no product was obtained from any of the 20 samples by the B. dermatitidis PCR assay. In conclusion, the PCR targeting a gene encoding the unique WI-1 adhesin is as sensitive as but more specific than the PCR targeting the 18S rDNA for detection of B. dermatitidis in canine tissue.

Early detection, aggressive therapy: Optimizing the management of feline mammary masses

Aims This article reviews the incidence, etiology, diagnosis, treatment and prognosis of mammary tumors in cats. Practical relevance Approximately 80% of feline mammary masses are malignant, with adenocarcinoma being the most common tumor type. Early diagnosis is, therefore, essential to improve the prognosis and quality of life of affected cats. Treatment approaches Surgery is the most widely used treatment for malignant tumors. However, as mammary tumors are often advanced and metastasis has already occurred by the time of diagnosis, surgery routinely does not provide a cure. Ovariohysterectomy or hormonal therapy are the treatments of choice for fibroadenomatous hyperplasia (the most common benign mass) and usually lead to a successful outcome.

Ultrasonographic and cytopathological diagnosis of exocrine pancreatic carcinoma in the dog and cat.

This study describes the ultrasonographic and cytopathological characteristics of malignant neoplasms of the exocrine pancreas and their value in making an antemortem diagnosis. The medical records of eight dogs and five cats were reviewed. The clinical presentations were variable and at times mimicked pancreatitis. Overall, cytopathology of ultrasound or fluoroscopic-guided biopsies or fine-needle aspirates, or impressions from surgical biopsies were helpful in establishing the diagnosis in 10 of 12 animals where it was performed. Histopathology of ultrasound or fluoroscopic-guided biopsies provided a diagnosis in five of six cases where it was performed.

Effect of Polyprenyl Immunostimulant on the survival times of three cats with the dry form of feline infectious peritonitis

Feline infectious peritonitis (FIP) is considered a fatal disease. Three cats with dry form FIP were treated with Polyprenyl Immunostimulant. Two of the three cats are still on treatment and are alive and well 2 years after diagnosis. The third cat survived 14 months but was treated for only 4.5 months. Further studies are necessary to assess the potential of the Polyprenyl Immunostimulant.

Sensitivity and specificity of an isoelectric focusing fraction of Blastomyces dermatitidis yeast lysate antigen for the detection of canine blastomycosis

Summary. Blastomyces dermatitidis yeast lysate antigen (T‐58, dog isolate) fractions prepared using the Rotofor® preparative isoelectric focusing (IEF) cell (Bio‐Rad) were compared with B. dermatitidis yeast lysate and filtrate reagents with respect to the detection of antibodies in sera from dogs with blastomycosis, histoplasmosis, coccidioidomycosis, cryptococcosis and aspergillosis. A horseradish peroxidase enzyme immunoassay with Turbo TMB substrate was used in the study. One particular IEF fraction (pH 4.3) was optimal in the assay, and it exhibited greater sensitivity (100%) and specificity (93%) than the lysate or filtrate preparations. The highest degree of cross‐reactivity was encountered with the histoplasmosis and coccidioidomycosis specimens and considerably less with the cryptococcosis and aspergillosis sera. Studies are in progress to purify further the optimal IEF fraction.

Characterization of Uptake of 2-Deoxy-2-[18F] Fluoro-D-Glucose by Fungal-Associated Inflammation: The Standardized Uptake Value is Greater for Lesions of Blastomycosis than for Lymphoma in Dogs with Naturally Occurring Disease

PURPOSE Based on limited reports, fungal lesions can have remarkably high intensity uptake of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) on positron emission tomography (PET) images. The purpose of this investigation was to compare the standardized uptake value (SUV) of naturally occurring lesions of blastomycosis with the SUV of naturally occurring lymphoma in a series of dogs. PROCEDURES Five dogs with naturally occurring blastomycosis and three dogs with lymphoma underwent whole-body FDG-PET prior to receiving any treatment for their disease. RESULTS The (mean +/- SD) SUV for 13 blastomycosis lesions was 7.7 +/- 2.0 versus a mean for 17 lymphomas of 4.8 +/- 1.8. These values were significantly different (P = 0.0537). There was overlap between the SUV of Blastomyces-associated lesions versus lymphomas, but a cut-off SUV of 7.0 was 100% specific for Blastomyces lesions. Numerous sites of disease were detected on the FDG-PET images that were not detected clinically. CONCLUSIONS FDG-PET is useful for determining the extent of disease in dogs with blastomycosis. The SUV for Blastomyces-associated lesions are as high or higher than for malignant lymphoma. Due to the similarities in canine and human blastomycosis and lymphomas, similar results would be predicted in human patients. In regions where blastomycosis is endemic, Blastomyces granulomas should be considered a differential diagnosis for lesions with high intensity uptake of FDG.