Retrospective evaluation of toceranib phosphate (Palladia®) toxicity in cats

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.

Metastatic feline mammary cancer: prognostic factors, outcome and comparison of different treatment modalities - a retrospective multicentre study

OBJECTIVES

Although feline mammary carcinomas (FMCs) are highly metastatic, the literature and treatment options pertaining to advanced tumours are scarce. This study aimed to investigate the clinical outcome of metastatic FMC with or without adjuvant treatment.

METHODS

The medical records of 73 cats with metastatic FMC (stage IV) were reviewed and included in this study. Metastatic disease was detected by distinct imaging techniques (radiography, ultrasound and CT) and confirmed by cytology and/or histopathology. Cats with adjuvant chemotherapy treatment (n = 34) were divided into three groups: group 1 (n = 9) cats receiving maximum tolerated dose chemotherapy; group 2 (n = 15) cats receiving metronomic chemotherapy; and group 3 (n = 10) cats treated with toceranib phosphate. The study endpoints were time to progression (TTP) and tumour-specific survival (TSS). Treatment-related toxicity was evaluated according to the Veterinary Co-operative Oncology Group's Common Terminology Criteria for Adverse Events version 1.1 (VCOG-CTCAE).

RESULTS

Overall mean TTP and TSS were 23 and 44 days, respectively. Cats with clinical signs at the time of diagnosis had a lower TSS (14 days) than asymptomatic cats (128 days; P <0.001). Cats with pleural effusion had a lower TSS (16 days) than cats without (P <0.001). Median TSS was 58, 75 and 63 days in groups 1, 2 and 3, respectively (P = 0.197). Toxicity was observed in 66.7%, 20% and 30% of cats in groups 1, 2 and 3, respectively.

CONCLUSIONS AND RELEVANCE

To the best of our knowledge, this study includes the highest number of patients with metastatic FMC assessed. Despite the overall poor prognosis, some cats survived >6 months, indicating that adjuvant treatment may be an option to consider in metastatic disease. More studies are warranted for better understanding and management of stage IV patients.

Rare-Earth-Doped Cerium Oxide Nanocubes for Biomedical Near-Infrared and Magnetic Resonance Imaging

Near-infrared (NIR) fluorescence provides a new avenue for biomedical fluorescence imaging that allows for the tracking of fluorophore through several centimeters of biological tissue. However, such fluorophores are rare and, due to accumulation-derived toxicity, are often restricted from clinical applications. Deep tissue imaging not only provided by near-infrared fluorophores but also conventionally carried out by magnetic resonance imaging (MRI) or computed tomography (CT) is also hampered by the toxicity of the contrast agents. This work offers a biocompatible imaging solution: cerium oxide (CeO₂) nanocubes doped with ytterbium or neodymium, and co-doped with gadolinium, showing simultaneous potential for near-infrared (NIR) fluorescence and magnetic resonance imaging (MRI) applications. A synthetic process described in this work allows for the stable incorporation of ytterbium or neodymium, both possessing emissive transitions in the NIR. As a biocompatible nanomaterial, the CeO₂ nanocubes act as an ideal host material for doping, minimizing lanthanide fluorescence self-quenching as well as any potential toxicity associated with the dopants. The uptake of nanocubes by HeLa cells maximized at 12 h was monitored by hyperspectral imaging of the ytterbium or neodymium NIR emission, indicating the capacity of the lanthanide-doped nanocubes for in vitro and a potential for in vivo fluorescence imaging. The co-doped nanocubes demonstrate no significant loss of NIR emission intensity upon co-doping with 2 atomic % gadolinium and exhibit magnetic susceptibilities in the range of known negative contrast agents. However, a small increase to 6 atomic % gadolinium significantly affects the magnetic susceptibility ratio (r₂/r₁), shifting closer to the positive contrast range and suggesting the potential use of the CeO₂ nanocube matrix doped with selected rare-earth ions as a tunable MRI contrast agent with NIR imaging capabilities.

Canine and Feline Cutaneous Mast Cell Tumor: A Comprehensive Review of Treatments and Outcomes

Mast cell tumor (MCT) or mastocytoma is one of the most frequent malignant cutaneous tumors in the dog, and the second most frequent in the cat. Several mast cell tumor therapeutic approaches have been proposed in the past years for dogs and cats, resulting in very distinct outcomes. The current comprehensive literature review presents a critical approach to the scientific information published about the MCTs treatments and the subsequent prognosis and survival times, in dogs and in cats diagnosed with MCTs. A systematic review of the literature following the Cochrane principles and methodology was performed. The authors resorted to MEDLINE, Scopus, Google Scholar and Web of Science databases to select the 133 publications with evidence-based treatments for MCTs in companion animals. Results of the review suggest that the recommended treatment, prognosis and survival times for dogs and cats with MCTs depends at all times on the clinical staging, histological grade and location of the tumor.

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.

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.

External beam radiotherapy for the treatment of feline salivary gland carcinoma: six new cases and a review of the literature

CASE SERIES SUMMARY

Salivary gland carcinoma is uncommon in cats. We report the outcome of radiation therapy in six cases (four salivary gland adenocarcinomas, one tubulopapillary adenocarcinoma, one carcinoma). Five were treated after surgical excision of the primary tumour, but four had gross disease (primary or metastatic) at the time of starting radiotherapy. Exact progression-free interval from the start of radiotherapy in the two cats where this was known was 120 and 144 days, respectively. One cat was signed off at 766 days with no evidence of recurrence. Another cat was in remission at 202 days (when last seen by the referring practice) but subsequently developed recurrence (date uncertain). Survival time was known for three cats (55 days, 258 days and 570 days from initiation of radiotherapy, respectively). In two cases, locoregional progressive disease (PD) was confirmed, and the other presumed as the cause of death. Two cats, known to have developed PD, were alive at the time of writing (at 206 and 549 days, respectively). No cat died as a result of distant metastatic disease.

RELEVANCE AND NOVEL INFORMATION

There is a paucity of information on the treatment of salivary gland tumours. In humans, as in cats, there is no optimised standard of care for malignant tumours. It is accepted that, for surgical candidates (even with large tumours), surgery and radiotherapy is superior to radiotherapy alone. However, the benefits of postoperative radiotherapy compared with surgery alone are only clear in patients with high-risk tumours (ie, those with large and invasive primary tumours, close or incomplete margins, high histopathological grade, histological evidence of neural or vascular invasion, or positive lymph nodes). This population is analogous to the population reported here, and likely to most cats presented in practice. Thus, radiation therapy may help improve locoregional control and survival in cats.

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.

Multimodal non-surgical treatment of a feline tracheal adenocarcinoma

CASE SUMMARY

A 10-year-old, castrated male domestic shorthair cat presented with a 2-3 month history of weight loss, lethargy and coughing. Thoracic radiographs revealed a soft tissue opacity overlying the dorsal trachea from the first rib to second rib and the ventral aspect of the trachea extending from the second rib to approximately the fourth rib. CT confirmed a mass involving the dorsal, right lateral and ventral aspects of the trachea narrowing the lumen and extending from vertebra C7 through T4. Bronchoscopy revealed a partially circumferential irregular and multilobulated tracheal mass, which was biopsied. The histopathological diagnosis was tracheal adenocarcinoma. The cat was treated with a definitive course of external beam radiation therapy (RT; 3 Gy × 18), cytotoxic chemotherapy, a tyrosine kinase inhibitor and palliative RT. The cat remained asymptomatic for 2 months and the mass remained stable radiographically for 11 months after RT.

RELEVANCE AND NOVEL INFORMATION

With multimodal treatment the cat had a survival time of 755 days. Initial treatment included definitive RT, carboplatin and piroxicam, followed by toceranib phosphate and palliative RT when the mass recurred. This case report describes the first documented use of non-surgical treatment and long-term outcome of tracheal adenocarcinoma in a cat. This case report is an indication that prolonged survival can be achieved with multimodal therapy.