Feline high-grade and large granular lymphocyte alimentary lymphomas treated with COP- or CHOP-based chemotherapy: A multi-centric retrospective study of 57 cases

Specific data regarding outcome of cats with high-grade and large granular lymphocyte alimentary lymphoma (HGAL and LGL, respectively) treated with multi-agent chemotherapy are scarce. The aims of this multi-centric, retrospective study were to describe the outcome of cats with HGAL and LGL treated with COP- or CHOP-based chemotherapy and to identify potential prognostic factors. Cats with a cytological or histological diagnosis of HGAL or LGL lymphoma treated with COP- or CHOP-based protocol as first-line chemotherapy were included. Data regarding diagnosis, staging, treatment and follow-up were collected. Fifty-seven cats treated with CHOP (n = 37) or COP (n = 20) protocols were included. Complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) were observed in 20%, 22%, 36% and 22% of cats, respectively, for an overall response rate of 42%. Median progression-free interval (PFI) was 148 days and overall median survival time (OST) was 131 days. Cats achieving CR, PR or SD showed significantly longer PFI (p < .01) and OST (p < .015) compared with cats with PD. Other positive prognostic factors in multi-variate analysis were rescue treatment (p < .001) and absence of lymph node involvement (p < .03). Negative prognostic factors were diffuse infiltration of the gastrointestinal tract (p = .035) and infiltration of a non-haematopoietic organ (p < .01).

Descriptive analysis and prognostic factors in cats with myeloma-related disorders: A multicenter retrospective study of 50 cases

BACKGROUND

Myeloma-related disorders (MRDs) are rare and poorly documented neoplasms of cats.

HYPOTHESIS/OBJECTIVES

To describe clinical, clinicopathologic, and imaging findings, response to treatment, and survival time and to identify factors associated with shorter outcomes in cats with MRD.

ANIMALS

Fifty cats with a diagnosis of MRD.

METHODS

Cats with paraproteinemia confirmed by serum protein electrophoresis (SPE) and either intramedullary plasmacytosis >10%, marked cytonuclear atypia with intramedullary plasmacytosis that ranged between 5% and 10%, or cytologically or histologically confirmed visceral infiltration were retrospectively included from several veterinary referral centers.

RESULTS

Bone marrow plasmacytosis and splenic or hepatic involvement were present in 17/27 cats (63%), 36/42 cats (86%), and 27/38 cats (71%), respectively. Anemia was reported in 33/49 cats (67%) and thrombocytopenia in 16/47 cats (34%). Some of the treatments that the cats received included melphalan and prednisolone (n = 19), cyclophosphamide and prednisolone (n = 10), chlorambucil and prednisolone (n = 4), prednisolone (n = 4), or other (n = 4). The overall response rates to melphalan, cyclophosphamide, and chlorambucil in combination with prednisolone were 87%, 90%, and 100%, respectively. Adverse events to melphalan or cyclophosphamide occurred in 65% and 23% of cats, respectively. Median survival time was 122 days (range, 0-1403) and was not significantly associated with chemotherapy protocol. Anemia (hazard ratio [HR], 3.1; 95% confidence interval [CI], 1.0-9.8) and thrombocytopenia (HR, 2.7; 95% CI, 1.2-6.0) were risk factors for shorter survival.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our study confirmed the guarded prognosis of MRD in cats and identified risk factors for shorter survival times.

Clinical, pathologic, and molecular characterization of a non-metastatic multicentric cutaneous mast cell tumor in a cow

Cutaneous mast cell tumors are rarely reported in cattle. Although mutations in the c-KIT gene have been shown to play a central role in the oncogenesis of canine mast cell tumors, few data are available in cattle. This report describes the clinical, histologic, immunohistochemical, and genetic features of a multicentric cutaneous mast cell tumor in an adult cow. An 11-year-old Prim'Holstein cow was presented for a 5-month history of multiple skin nodules. Cytologic and histologic analyses of the nodules led to a diagnosis of mast cell tumors. Immunohistochemical analysis for KIT expression showed a moderate to strong signal in neoplastic mast cells with a cytoplasmic and membranous pattern. Sequencing of the c-KIT gene coding sequence revealed no mutation. Despite partial response after corticosteroid treatment, euthanasia was elected. No metastases to the lymph nodes, spleen, and liver were identified at post-mortem and histologic examinations.

Oncolytic virotherapy with intratumoral injection of vaccinia virus TG6002 and 5-fluorocytosine administration in dogs with malignant tumors

TG6002 is an oncolytic vaccinia virus expressing FCU1 protein, which converts 5-fluorocytosine into 5-fluorouracil. The study objectives were to assess tolerance, viral replication, 5-fluorouracil synthesis, and tumor microenvironment modifications to treatment in dogs with spontaneous malignant tumors. Thirteen dogs received one to three weekly intratumoral injections of TG6002 and 5-fluorocytosine. The viral genome was assessed in blood and tumor biopsies by qPCR. 5-Fluorouracil concentrations were measured in serum and tumor biopsies by liquid chromatography or high-resolution mass spectrometry. Histological and immunohistochemical analyses were performed. The viral genome was detected in blood (7/13) and tumor biopsies (4/11). Viral replication was suspected in 6/13 dogs. The median intratumoral concentration of 5-fluorouracil was 314 pg/mg. 5-Fluorouracil was not detected in the blood. An increase in necrosis (6/9) and a downregulation of intratumoral regulatory T lymphocytes (6/6) were observed. Viral replication, 5-fluorouracil synthesis, and tumor microenvironment changes were more frequently observed with higher TG6002 doses. This study confirmed the replicative properties, targeted chemotherapy synthesis, and reversion of the immunosuppressive tumor microenvironment in dogs with spontaneous malignant tumors treated with TG6002 and 5-fluorocytosine.

Myelomatous pleural effusion in a cat diagnosed with multiple myeloma

Case summary

A 10-year-old male castrated domestic shorthair cat was presented with a 3-day history of dyspnoea, chronic lethargy and inappetence. A bilateral pleural effusion was identified by thoracic ultrasound, and cytological examination revealed numerous atypical plasma cells. Biochemistry and serum protein electrophoresis revealed a severe hyperglobulinaemia associated with a monoclonal gammopathy. A moderate non-regenerative anaemia was also noted. Multiple bone lytic lesions were detected, and marked plasmacytosis was observed on bone marrow aspirates. Chemotherapy with cyclophosphamide and prednisolone was initiated but did not result in any clinical or biological response, and pleural effusion recurred. Lack of therapeutic response led to euthanasia 2 months after diagnosis.

Relevance and novel information

This is the first description of a myelomatous pleural effusion in a cat diagnosed with multiple myeloma and should be considered as one of the possible differential diagnoses for cats presented with pleural effusion and hyperglobulinaemia. The diagnostic, therapeutic and prognostic aspects of this manifestation are discussed.

Blood biomarkers for canine cancer, from human to veterinary oncology

In recent decades, interest in circulating tumour biomarkers is increasing both in human and veterinary oncology. An ideal tumour biomarker would allow early diagnosis of neoplasia, identify it specifically, accurately, establish a prognosis and predict its behaviour, especially regarding different therapeutic solutions. It would also allow to monitor its evolution over time and all this in a non-invasive and inexpensive way. Actually, no biomarkers meeting all of these criteria have been identified in veterinary medicine, particularly due to a lack of specificity of the main protein tumour biomarkers studied to date. However, great hope is currently placed in biomarkers grouped under the name of liquid biopsy, which could prove to be effective tools for common clinical use in the near future. This review gives an update on blood cancer biomarkers studied in dogs, such as ions, proteins, nucleic acids and also circulating cells, of which some might become more prominent in the coming years to help improve the management of animal care.

[Long-term follow-up of a multimodally managed pulmonary mucoepidermoid carcinoma in a cat]

INTRODUCTION

The present case describes the treatment of a mucoepidermoid carcinoma in a 13-year-old female sterilized European domestic cat, using lung lobectomy and -accompanying mitoxantrone chemotherapy. Six, 14, 19 and 27 months after the initial treatment tomodensitometric and radiographic examinations showed no abnormalities. However, the cat had to be euthanized 27 months after the lung lobectomy due to a soft tissue sarcoma in the interscapular area.

Outcome of dogs and cats with benign oesophageal strictures after balloon dilatation or stenting: 27 cases (2002-2019)

OBJECTIVES

Acquired oesophageal strictures remain challenging to manage in canine and feline patients. The aims of this study were to describe the treatment, complications, short-term outcome and long-term follow-up of benign oesophageal strictures treated by balloon dilatation or stenting in dogs and cats and to describe adjunctive techniques to minimise the complication rate of stent placement.

MATERIALS AND METHODS

Retrospective analysis of medical records of dogs and cats with benign oesophageal stricture diagnosed under endoscopy between 2002 and 2019.

RESULTS

Eighteen dogs and nine cats were included, representing 39 strictures. Balloon dilatation was used as first-line therapy, with a good outcome in 59% of cases. Stents were placed in eight cases due to stricture recurrence; 88% had a long-term satisfactory outcome. Short-term complications occurred in six of eight cases; migration and aberrant mucosal reaction were uncommon. In three cases, progressive mesh cutting during follow-up reduced discomfort and trichobezoars formation and improved long-term stent tolerance. Overall median survival time was 730 days.

CLINICAL SIGNIFICANCE

Long-term prognosis of balloon dilatation as a first-line therapy for esophageal strictures and of stenting as a rescue therapy was considered satisfactory. Although discomfort associated with stenting was frequent, tolerability might be improved by per-endoscopic adjunctive techniques.

Pharmacokinetics and tolerance of repeated oral administration of 5-fluorocytosine in healthy dogs

Background

5-fluorocytosine is a pyrimidine and a fluorinated cytosine analog mainly used as an antifungal agent. It is a precursor of 5-fluorouracil, which possesses anticancer properties. To reduce systemic toxicity of 5-fluorouracil during chemotherapy, 5- fluorocytosine can be used as a targeted anticancer agent. Expression of cytosine deaminase by a viral vector within a tumor allows targeted chemotherapy by converting 5-fluorocytosine into the cytotoxic chemotherapeutic agent 5-fluorouracil. However, little is known about the tolerance of 5-fluorocytosine in dogs after prolonged administration.

Results

In three healthy Beagle dogs receiving 100 mg/kg of 5-fluorocytosine twice daily for 14 days by oral route, non-compartmental pharmacokinetics revealed a terminal elimination half-life of 164.5 ± 22.5 min at day 1 and of 179.2 ± 11.5 min, after 7 days of administration. Clearance was significantly decreased between day 1 and day 7 with 0.386 ± 0.031 and 0.322 ± 0.027 ml/min/kg, respectively. Maximal plasma concentration values were below 100 µg/ml, which is considered within the therapeutic margin for human patients. 5-fluorouracil plasma concentration was below the limit of detection at all time points. The main adverse events consisted of depigmented, ulcerated, exudative, and crusty cutaneous lesions 10 to 13 days after beginning 5-fluorocytosine administration. The lesions were localized to the nasal planum, the lips, the eyelids, and the scrotum. Histological analyses were consistent with a cutaneous lupoid drug reaction. Complete healing was observed 15 to 21 days after cessation of 5-fluorocytosine. No biochemical or hematological adverse events were noticed.

Conclusions

Long term administration of 5-fluorocytosine was associated with cutaneous toxicity in healthy dogs. It suggests that pharmacotherapy should be adjusted to reduce the toxicity of 5-fluorocytosine in targeted chemotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02927-5.

Safety, biodistribution and viral shedding of oncolytic vaccinia virus TG6002 administered intravenously in healthy beagle dogs

Oncolytic virotherapy is an emerging strategy that uses replication-competent viruses to kill tumor cells. We have reported the oncolytic effects of TG6002, a recombinant oncolytic vaccinia virus, in preclinical human xenograft models and canine tumor explants. To assess the safety, biodistribution and shedding of TG6002 administered by the intravenous route, we conducted a study in immune-competent healthy dogs. Three dogs each received a single intravenous injection of TG6002 at 105 PFU/kg, 106 PFU/kg or 107 PFU/kg, and one dog received three intravenous injections at 107 PFU/kg. The injections were well tolerated without any clinical, hematological or biochemical adverse events. Viral genomes were only detected in blood at the earliest sampling time point of one-hour post-injection at 107 PFU/kg. Post mortem analyses at day 35 allowed detection of viral DNA in the spleen of the dog which received three injections at 107 PFU/kg. Viral genomes were not detected in the urine, saliva or feces of any dogs. Seven days after the injections, a dose-dependent antibody mediated immune response was identified. In conclusion, intravenous administration of TG6002 shows a good safety profile, supporting the initiation of clinical trials in canine cancer patients as well as further development as a human cancer therapy.

Preclinical Evaluation of the Oncolytic Vaccinia Virus TG6002 by Translational Research on Canine Breast Cancer

Oncolytic virotherapy is a promising therapeutic approach for the treatment of cancer. TG6002 is a recombinant oncolytic vaccinia virus deleted in the thymidine kinase and ribonucleotide reductase genes and armed with the suicide gene FCU1, which encodes a bifunctional chimeric protein that efficiently catalyzes the direct conversion of the nontoxic 5-fluorocytosine into the toxic metabolite 5-fluorouracil. In translational research, canine tumors and especially mammary cancers are relevant surrogates for human cancers and can be used as preclinical models. Here, we report that TG6002 is able to replicate in canine tumor cell lines and is oncolytic in such cells cultured in 2D or 3D as well as canine mammary tumor explants. Furthermore, intratumoral injections of TG6002 lead to inhibition of the proliferation of canine tumor cells grafted into mice. 5-fluorocytosine treatment of mice significantly improves the anti-tumoral activity of TG6002 infection, a finding that can be correlated with its conversion into 5-fluorouracil within infected fresh canine tumor biopsies. In conclusion, our study suggests that TG6002 associated with 5-fluorocytosine is a promising therapy for human and canine cancers.

Abstract 1446: Characterization, evaluation and safety studies of the oncolytic Vaccinia virus TG6002 for canine cancer therapy

Introduction: Oncolytic virotherapy with tumor selective viruses, such as Vaccinia viruses (VV), offers a promising treatment modality for cancer. TG6002 is a recombinant oncolytic VV deleted in two viral genes (thymidine kinase and ribonucleotide reductase) and armed with the suicide gene FCU1 that encodes a bifunctional chimeric protein which efficiently catalyses the direct conversion of the nontoxic 5-fluorocytosine (5-FC) into the toxic metabolite 5-fluorouracil (5-FU). Canine tumors are relevant predictive preclinical surrogates for human oncology. The first objective was to evaluate the susceptibility, the replication rate and the oncolytic potency of VV in canine tumor cell lines. The second objective was to evaluate oncolytic potency of TG6002 in xenograft model and fresh canine tumor biopsies. The third objective was to assess safety and viral shedding of TG6002 in healthy dogs.

Materials and Methods: Transduction efficiency, replication and oncolytic potency of TG6002 were evaluated in vitro in a variety of different canine cancer cell lines. In vivo anti-tumor effect of TG6002 was examined in a canine tumor xenograft model. TG6002 was injected intratumorally or intravenously with or without 5-FC. Three canine mammary adenocarcinoma explants were infected with TG6002 in presence of 5-FC during 6 days. Oncolytic potency was assessed by histological exams. Concentrations of 5-FC and 5-FU were monitored. TG6002 was administered intramuscularly for 7 healthy dogs and intravenously for 4 healthy dogs. Clinical exams, complete blood count and biochemistry analysis were performed. Blood, saliva, urine, feces were collected for virus detection by qPCR and plaque assay.

Results: Canine cell lines were highly susceptible to VV infection. A replication factor of 106 to 107 was determined 4 days after infection and a significant reduction of cell viability was noticed 5 days after infection. In xenograft model, intratumoral or intravenous injections of TG6002 with oral 5-FC induced a significant inhibition of tumor growth compared to control groups. In canine mammary adenocarcinoma biopsies, a lysis of 90% of tubular cells was observed on histological exams. Conversion of more than 50% of 5-FC to 5-FU was noticed. In healthy dogs, a good tolerance of intramuscular and intravenous injections of TG6002 without viral shedding was assessed.

Conclusion: This study demonstrates that TG6002 is able to infect and replicate in canine tumor cell lines and is oncolytic in both cell lines, xenograft model and canine mammary adenocarcinoma samples. This study also confirms that TG6002 can be safely administered in dogs. These promising results support the use of TG6002 in a clinical trial for both human and canine species. This study emphasizes the importance of a One Health approach in oncology.

Citation Format: Jérémy Béguin, Johann Foloppe, Eve Laloy, Virginie Nourtier, Isabelle Farine, Murielle Gantzer, Christelle Pichon, Sandrine Cochin, Pascale Cordier, Dominique Tierny, Jean Marc Balloul, Eric Quémeneur, Christelle Maurey, Bernard Klonjkowski, Philippe Erbs. Characterization, evaluation and safety studies of the oncolytic Vaccinia virus TG6002 for canine cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1446.

The myeloid derived suppressor cells: Who are they? Can they be used as a diagnostic tool to investigate metastasis in veterinary medicine?

Myeloid-derived suppressor cells (MDSCs) are key players in immunosuppression mechanisms that lead to tumor escape and metastasis formation. Studies on these cells in many cancer types using human patients and murine models, have greatly increased since their discovery in 1980s. MDSCs are now defined as different subpopulations with specific phenotypes in mice and humans with clear immunosuppressive capacities, which are summarized in this review. Current knowledge on these cells have allowed comparative studies and MDSCs have also recently been identified in dogs. As in other species, canine MDSCs have immunosuppressive activities and their number is increased in blood of metastasis-bearing dogs. Circulating MDSCs could therefore represent a new biomarker for cancer progression in both veterinary and human medicine. Further characterization of these cells in other cancer-suffering animal species would also be of great interest.

[Villonodular synovitis of the knee. Analysis of a series of 17 cases and review of the literature]

PURPOSE OF THE STUDY

Pigmented villonodular synovitis is a rare pathology found predominantly in the knee. We report management and treatment of 17 cases of pigmented villonodular synovitis of the knee.

MATERIAL AND METHODS

The mean follow-up was 9 years (maximum: 17 years). The diagnosis was always confirmed at histopathology. There were 12 women and 5 men. The average age at the initial symptoms was 28 years. Six cases were diffuse, 7 localized and 4 cases were mixed.

RESULTS

First treatment was only arthroscopic in 8 cases, and open synovectomy in 6 cases and mixed in 2 cases. Six patients had a recurrence, one had more than one recurrence. The mean delay for recurrence was 2 years and 5 months. Loss of range of motion was noted in 6 cases. For these 6 cases, flexion was always greater than 90 degrees and flessum always inferior to 10 degrees.

DISCUSSION

Ethiopathogeny of this disease is unclear and no etiopathogenic theory is defined. Magnetic resonance imaging is useful for diagnosis, and absolutely necessary for preoperative tumor localization, and also for survey. In localized types, arthroscopic synovectomy can be performed with success but in diffuse or mixed form an open synovectomy must be performed according to the high rate or recurrence observed after incomplete synovectomy. Synoviorthesis with Yttrium 90 seems to be a good adjuvant for the treatment of recurrent pigmented villonodular synovitis.

CONCLUSION

Arthroscopy is the treatment of choice for localized forms. We propose a mixed concept with an anterior and parameniscal arthroscopic synovectomy (without meniscectomy), an open synovectomy for the posterior localization, and an open anterior synovectomy when the tumor mass is too voluminous.