The tyrosine kinase inhibitor toceranib in feline injection site sarcoma: efficacy and side effects

The incidence and trends of proteinuria, azotemia and hypertension in cats receiving toceranib phosphate

OBJECTIVES

This retrospective study aimed to determine the incidence and trends of proteinuria, elevations in serum creatinine and urea, and systolic blood pressure in cats undergoing treatment with toceranib.

METHODS

In total, 32 cats treated with toceranib for malignancies were analyzed. Cats were included if urinalysis and urine protein:creatinine ratio (UPC) measurements were available at 28 days (T1) and 56 days (T2) after starting the treatment. Cats with concurrent lower urinary tract disease, including urinary tract malignancy, were excluded. Friedman's ANOVA compared variables between time points, and the Spearman test assessed the correlation between treatment duration and UPC.

RESULTS

The median starting dose of toceranib was 2.68 mg/kg (range 1.7-3.9). In total, 15 (46.9%) cats received concurrent non-steroidal anti-inflammatory drugs. The most commonly treated tumors were oral squamous cell carcinoma (n = 10) and mast cell tumor (n = 5). None of the 32 cats developed progressive proteinuria or azotemia during the follow-up period (median 56 days; range 56-336). Notably, UPC and serum creatinine were significantly lower at T2 compared with baseline (P = 0.012 and 0.001, respectively). Among the four cats with baseline proteinuria, UPC decreased over time with or without concurrent telmisartan treatment (n = 2). All four of these cats experienced a reduction in tumor size with toceranib concurrently with their decreased UPC. There was no significant correlation between UPC and the duration of toceranib treatment (P = 0.089). Blood pressure was not significantly different over the assessed time points.

CONCLUSIONS AND RELEVANCE

The incidence of proteinuria, renal azotemia and hypertension in cats treated with toceranib for neoplasia appears to be low. Toceranib may be a viable treatment option even in cats with pre-existing proteinuria or renal disease, with careful monitoring of trends recommended.

Evaluation of the efficacy and safety of toceranib phosphate in cats with macroscopic mammary adenocarcinoma

OBJECTIVES

Mammary tumours in cats are biologically aggressive. The standard of care relies upon wide surgical resection. Chemotherapy has been described in the macroscopic disease setting; however, limited efficacy has been shown. The aim of this study was to assess the efficacy of toceranib phosphate in macroscopic feline mammary tumours (FMTs).

METHODS

A total of 17 cats with cytologically or histopathologically confirmed mammary adenocarcinoma (gross disease) were prospectively enrolled. Toceranib phosphate was administered at a median dose of 2.77 mg/kg (range 2.3-3.2) PO q48 h. No corticosteroids or non-steroidal anti-inflammatory drugs (NSAIDs) were administered. Toxicity was graded according to Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events (VCOG-CTCAE) v1.1 criteria. The response was assessed after 1 month, following Response Evaluation Criteria In Solid Tumours (RECIST) criteria.

RESULTS

Toxicity was observed in eight cats, with most instances being grade 1 or 2, which were managed with supportive care. Only one cat experienced grade 3 toxicity (anorexia), which resolved after a dose reduction. Clinical benefit was seen in 12 (64.7%) cats and an objective response was seen in six (35.2%) cats. One cat experienced complete response, five had partial response, six had stable disease and five had progressive disease. One cat showed distant progression (malignant pleural effusion) despite continued partial remission of the primary tumour. The median progression-free survival and median overall survival time were 91 days (range 30-158) and 145 days (range 31-234), respectively.

CONCLUSIONS AND RELEVANCE

Toceranib phosphate showed clinical benefit and a good safety profile in advanced or recurrent FMTs, offering a new alternative in the treatment of this disease; however, further prospective and randomised studies are required to further assess its efficacy. Interestingly, one cat developed distant metastases while the primary tumour showed partial response, suggesting that primary tumour and metastatic disease may not sustain the same sensitivity to toceranib.

A Scoping Review on Tyrosine Kinase Inhibitors in Cats: Current Evidence and Future Directions

Tyrosine kinase inhibitors (TKIs) have become invaluable in the treatment of human and canine malignancies, but their role in feline oncology is less defined. While toceranib phosphate and masitinib mesylate are licensed for use in dogs, no TKI is yet approved for cats. This review systematically maps the research conducted on the expression of tyrosine kinases in neoplastic and non-neoplastic domestic feline tissues, as well as the in vitro/in vivo use of TKIs in domestic cats. We identify and discuss knowledge gaps and speculate on the further research and potential indications for TKI use in cats. A comprehensive search of three electronic databases and relevant paper reference lists identified 139 studies meeting the inclusion criteria. The most commonly identified tumors were mast cell tumors (MCTs), mammary and squamous cell carcinomas and injection-site sarcomas. Based on the current literature, toceranib phosphate appears to be the most efficacious TKI in cats, especially against MCTs. Exploring the clinical use of TKIs in mammary carcinomas holds promise. Despite the progress, currently, the evidence falls short, underscoring the need for further research to discover new indications in feline oncology and to bridge the knowledge gaps between human and feline medicine.

Feline restrictive orbital myofibroblastic sarcoma treated with toceranib phosphate (Palladia) as adjuvant chemotherapy: A case study of one cat

Key Clinical Message

This is the first case report of treatment with toceranib phosphate as postsurgical adjuvant chemotherapy for advanced FROMS. This reported case highlights the need for further studies on the efficacy of toceranib phosphate as adjuvant chemotherapy for FROMS.

Abstract

Feline restrictive orbital myofibroblastic sarcoma (FROMS) is a rare aggressive tumor in cats. We explored the effectiveness of using toceranib phosphate as postsurgical adjuvant chemotherapy for advanced FROMS in a 7-year-old cat. Despite treatment, the cat died 4 months after surgery. This report highlights the need for further studies on the efficacy of toceranib phosphate as adjuvant chemotherapy for FROMS.

Low dose meloxicam is safe and tolerable when combined with toceranib phosphate in cancer-bearing cats

OBJECTIVES

Non-steroidal anti-inflammatory drugs (NSAIDs) are infrequently utilized in cats due to concern for renal compromise; however, recent studies demonstrate tolerability of low dose meloxicam. Toceranib phosphate is used to treat several feline cancers and is well tolerated. This study aimed to determine the tolerability and adverse event profile of combined toceranib and low dose meloxicam in cancer-bearing cats. Secondary goals involved assessing anticancer tumor efficacy and impact upon quality of life and analgesia.

METHODS

Cats with any cancer not involving the kidneys were eligible. The study adopted a conventional 3 + 3 dose escalation design. Toceranib was administered every other day at a standard dose with meloxicam administered in an escalating fashion in subsequent cohorts, at a starting dose of 0.01 mg/kg on opposite days to toceranib, up to a maximum of 0.02 mg/kg daily, based upon previous safety studies. Laboratory work, blood pressure, tumor measurements, pain score and client-completed quality-of-life surveys were recorded every 2-4 weeks during the 12-week study period.

RESULTS

Twenty-one cats were enrolled. When combined with toceranib, a meloxicam dose of 0.02 mg/kg q24h was safe and well tolerated, with no cats being withdrawn due to adverse events from the drug combination. The majority of cats demonstrated clinical benefit with stable to mildly improved tumor measurements, quality of life and pain scores.

CONCLUSIONS AND RELEVANCE

Low dose meloxicam combined with toceranib is safe and well tolerated in cancer-bearing cats. Continued patient recruitment and data collection are needed to determine the maximum tolerated dose of meloxicam. The results of our study will guide further phase II/III trials.

Successful Treatment of Vertebral Osteosarcoma in a Cat Using Marginal Surgical Excision and Chemotherapy

A three-year-old male neutered Norwegian Forest cat was referred for bilateral ambulatory paraparesis and spinal pain. On magnetic resonance imaging (MRI), a mass involving the right epaxial muscles with vertebral canal invasion and causing marked extradural spinal cord compression was identified. At surgery, the mass was debulked and a right hemilaminectomy was performed. Histopathology was diagnostic of fibroblastic osteosarcoma. Residual osteolytic lesions of the osteosarcoma were present at the level of the spinous process of the second lumbar vertebra. Four cycles of adjuvant doxorubicin chemotherapy were administered followed by oral toceranib phosphate. Neurological signs improved gradually over weeks to months and the lesion in the spinous process was no longer visible on radiographs. At one year from diagnosis, an MRI of the T3-L3 (3rd thoracic vertebra to the 3rd lumbar vertebra) spinal region and a whole-body computer tomography (CT) scan found no evidence of the osteosarcoma in the spine or of any metastasis. All medications were stopped and, at the time of writing 16 months later, the patient is neurologically normal with no signs of cancer recurrence. This is the first case report documenting the complete resolution of vertebral osteosarcoma lesions after treatment with doxorubicin followed by toceranib phosphate. The treatment also prevented tumor recurrence and was associated with an exceptionally long-term survival time.

The role of toceranib phosphate in dogs with non-mast cell neoplasia: A systematic review

The use of tyrosine kinase inhibitors (TKI) has gained significant importance in veterinary cancer patients over the last decade. Toceranib phosphate has been licensed for the treatment of dogs with mast cell tumours. Its molecular similarity to sunitinib, a TKI used in human medicine, has led many veterinary oncologists to use this agent for multiple neoplastic diseases. The aim of the current study was to perform a systematic review of the evidence for the use of toceranib in dogs with non-mast cell neoplasia. Two electronic databases were searched. Publications were included if toceranib was used as a treatment option in canine patients. Studies and case reports were excluded if toceranib was used as part of a multi-modal treatment plan and response or outcome data related to toceranib therapy were not described. A total of 28 studies were included from 122 references. The most common types of neoplasias identified were neuroendocrine tumours, anal gland sac adenocarcinoma, and osteosarcoma. Multiple other neoplasias had one or two studies identified to describe the use of toceranib. Results of the study support that toceranib phosphate may have efficacy against certain types of neoplasia under certain conditions, such as neuroendocrine tumours, gastrointestinal stromal tumours and anal sac adenocarcinomas, while it is probably not effective for the management of metastatic osteosarcoma based on the findings of the review.

Gastrointestinal stromal tumour lacking mutations in the KIT and PDGFRA genes in a cat

Molecular subtyping in gastrointestinal stromal tumours is a useful method for predicting the efficacy of treatment using tyrosine kinase inhibitors in humans. However, owing to the paucity of reports on mutational analyses, the association between genetic mutations and the therapeutic response to tyrosine kinase inhibitors remains unclear in feline gastrointestinal stromal tumours. In this report, we describe the case of a cat with a gastrointestinal stromal tumour which was unresponsive to tyrosine kinase inhibitors. A mutational analysis revealed that the cat lacked mutations in both the KIT and platelet-derived growth factor receptor-alpha (PDGFRA) genes. Our findings are consistent with the fact that KIT/PDGFRA wild-type gastrointestinal stromal tumours are less responsive to tyrosine kinase inhibitors in humans. This signifies the need for further evaluation and possibly individualised treatment for gastrointestinal stromal tumours in cats on the basis of mutational analyses.

Management of a feline gastric stromal cell tumour with toceranib phosphate: a case study

BACKGROUND

A fifteen-year old, female spayed domestic longhaired cat was presented for a routine vaccination during which an incidental abdominal mass was palpated. After further inquiry, occasional vomiting was reported to occur once every few weeks to months, associated with no other gastrointestinal signs.

CASE REPORT

Ultrasonography revealed a gastric mass. Histopathology and immunohistochemistry confirmed a CD117 positive, smooth muscle actin and desmin negative neoplasm, consistent with a gastrointestinal stromal cell tumour (GIST). Treatment was initiated with toceranib phosphate resulting in stable disease for over eighteen months, and the patient was still alive at the time of writing.

CONCLUSION

GISTs are rare in cats and this is the first report of medical management of feline GIST using toceranib.

Role of nuclear factor-kappa B in feline injection site sarcoma

Background

Chronic inflammation has been implicated in sarcomagenesis. Among various factors, activation of nuclear factor-kappa B (NF-κB) signaling pathway has been documented being able to target genes associated with tumor progression and up-regulate the expression of tumor-promoting cytokines and survival genes in several human solid tumors. Feline injection sites sarcomas (FISS) are malignant entities derived from the mesenchymal origin. The disease has been considered to be associated with vaccine adjuvant, aluminum, which serves as a stimulus continuously inducing overzealous inflammatory and immunologic reactions. To understand the contribution of NF-κB in FISS, detection of activated NF-κB in paraffin-embedded specimens, in vitro establishment of primary cells derived from FISS, and evaluation of the effects of the NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on primary tumor cells were conducted.

Results

In this study, nuclear expression of NF-κB p65 was detected in 83.3% of FISS cases and not correlated with tumor grading, sex, and age. Primary cells derived from FISS in three cats exhibiting same immunohistochemical characteristics as their original tumor were successfully established. The NF-κB inhibitor, DHMEQ, was able to prevent nuclear translocation of NF-κB p65, inhibit cell proliferation, migration, and colonization in dosage-dependent manners, and induce cell apoptosis in these primary FISS cells.

Conclusions

High expression rate of nuclear NF-κB p65 in FISS cases and dose-dependent inhibitory effects on the growth of FISS primary cells treated with NF-κB inhibitor suggested that NF-κB might be a potential molecular therapeutic target for FISS.

Targeted Therapies in Veterinary Oncology

Advances in molecular biology have permitted a much more detailed understanding of cellular dysfunction at the molecular and genetic levels in cancer cells. This has resulted in the identification of novel targets for therapeutic intervention, including proteins that regulate signal transduction, gene expression, and protein turnover. In many instances, small molecules are used to disrupt the function of these targets, often through competitive inhibition of ATP binding or the prevention of necessary protein-protein interactions. More than 40 small molecule inhibitors are now approved to treat a variety of human cancers, substantially impacting patient outcomes.

Update on Cancer Treatment in Exotics

Treatment options for animals with cancer are rapidly expanding, including in exotic animal medicine. Limited information is available about treatment effects in exotic pet species beyond individual case reports. Most cancer treatment protocols in exotic animals are extrapolated from those described in humans, dogs, and cats. This review provides an update on cancer treatment in exotic animal species. The Exotic Species Cancer Research Alliance accumulates clinical cases in a central location with standardized clinical information, with resources to help clinicians find and enter their cases for the collective good of exotic clinicians and their patients.

Retrospective evaluation of toceranib phosphate (Palladia) use in cats with mast cell neoplasia

Objectives The purpose of this study was to solicit and compile data from practicing veterinary specialists regarding their use of toceranib in cats with mast cell neoplasia and to provide initial assessment of possible clinical benefit and adverse events. Methods The American College of Veterinary Internal Medicine and Oncology listservs were used to solicit data pertaining to cases in which toceranib was used in the treatment of feline mast cell neoplasia. Cases were included if the following data were received: signalment (age, sex, breed), diagnosis of mast cell neoplasia by either cytology or histopathology, anatomic classification of disease (cutaneous, splenic/hepatic, gastrointestinal, other), previous and concurrent treatment, toceranib dose (mg/kg) and schedule, duration of therapy, best response and documentation of adverse events. Results Case data from 50 cats with cutaneous (n = 22), splenic/hepatic (visceral) (n = 10), gastrointestinal (n = 17) or other (n = 1) mast cell neoplasia were received. Clinical benefit was seen in 80% (40/50), including 86% (19/22) with cutaneous, 80% (8/10) with visceral and 76% (13/17) with gastrointestinal involvement. A majority of cats (n = 35) received glucocorticoids during toceranib treatment. Median duration of treatment in cats experiencing clinical benefit was 36 weeks (range 4-106 weeks), 48 weeks (range 12-199 weeks) and 23 weeks (range 13-81 weeks) for cutaneous, visceral and gastrointestinal cases, respectively. Toceranib was administered at a median dose of 2.5 mg/kg (range 1.6-3.5 mg/kg); in 90% (45/50) the drug was given three times per week. Treatment was generally well tolerated with 60% (30/50) of cats experiencing adverse events. The majority of these events were low-grade (grade 1 or 2) gastrointestinal or hematologic events that resolved with treatment break and/or dose adjustment. Conclusions and relevance Toceranib appears to be well tolerated in feline patients with mast cell neoplasia. Biologic activity of this drug is evident in the studied cats; however, further prospective studies are needed to elucidate fully its role in treatment of this disease.

Current knowledge on feline injection-site sarcoma treatment

Feline injection-site sarcomas (FISS) are malignant skin tumours of mesenchymal origin, the treatment of which is a challenge for veterinary surgeons. The role of surgery, radiotherapy and chemotherapy in FISS treatment has been studied, and a correlation between “clean” surgical margins and disease-free survival has been shown. In addition, clean surgical margins are one of the most important factors for achieving a low recurrence rate. The most effective method of FISS treatment includes combining radical surgery with pre- or postoperative radiotherapy. Chemotherapy may be used as a palliative method of treatment or may be considered an adjunctive therapy for surgery and radiotherapy. In cats with FISS without metastasis, the use of immunostimulant treatment with Oncept IL-2, intended as a complementary immunotherapy in association with surgery and brachytherapy, may also be considered to reduce the risk of relapse and increase the time to relapse. Additionally, this review focuses on recent advances in FISS treatment, including the use of novel compounds, such as doxorubicin conjugated to glutathione-stabilized gold nanoparticles, liposomal doxorubicin or tyrosine kinase inhibitors.

Medical management of gastrinoma in a cat

Case summary

A 7-year-old male castrated domestic short-haired cat was evaluated for a 4 week history of intermittent vomiting, ptyalism, lethargy and weight loss. Serum biochemistry revealed mild mixed hepatopathy. Abdominal ultrasonography identified multiple heterogeneous hepatic masses and a linear, hyperechoic focus with associated reverberation artifact in the wall of the stomach consistent with a gastric ulcer. Serum gastrin concentrations were markedly increased. Cytologic interpretation of a fine-needle aspirate of the hepatic masses was consistent with neuroendocrine neoplasia, and a diagnosis of gastrinoma was established. Deterioration of the cat’s condition, despite at-home acid-suppressant therapy, led to hospitalization. The cat was initially stabilized with intravenous crystalloid fluid therapy, maropitant, pantoprazole and octreotide. A continuous radiotelemetric intragastric pH monitoring system was used to monitor the response of intragastric pH to therapy. Long-term therapy was continued with omeprazole (orally q12h), octreotide (subcutaneously q8h) and thrice-weekly toceranib administered orally. Toceranib therapy led to gastrointestinal upset and was discontinued. Gastric ulceration resolved within 8 weeks, and palliation of clinical signs was achieved for approximately 5 months.

Relevance and novel information

Including this report, only six cases of feline gastrinoma have been reported in the veterinary literature. Little is known regarding non-surgical therapy, and octreotide has not been previously reported for medical management of feline gastrinoma. Results of intragastric pH monitoring and clinical improvement suggest that medical therapy using octreotide and proton pump inhibitors represents a novel therapeutic option for cats with gastrinoma where surgical excision is not feasible.

Injection-Site Sarcoma in a Dog: Clinical and Pathological Findings

This case report documents the clinical and pathological findings in a dog that rapidly developed a high-grade sarcoma at the site of multiple vaccinations and follows the response to surgery and adjunct treatment with toceranib. An 11-year-old female spayed Labrador Retriever presented with dorsocervical subcutaneous masses at the injection site three weeks after receiving DA₂PP-Lepto, Rabies, and Bordetella vaccinations. A high-grade soft tissue sarcoma was diagnosed microscopically and immunohistochemistry revealed positive expression of VEGFr, PDGFr, SCF, and EGFR. Repeat surgical resections and targeted treatment with toceranib resulted in a stable remission for nearly two years.