Thirteen-week dose-intensifying simultaneous combination chemotherapy protocol for malignant lymphoma in dogs

Review of Canine Lymphoma Treated with Chemotherapy-Outcomes and Prognostic Factors

While canine lymphoma is a relatively common and important disease seen by veterinarians, there are limited comprehensive reviews of the literature regarding the remission and survival times following chemotherapy, and the associated prognostic factors. This comprehensive thematic review covers the available veterinary literature covering treatment outcomes and identified prognostic factors. A lack of standardised approaches to evaluate and report the outcomes was identified, including factors that would alter the duration of responses by weeks, or occasionally months. After publication of the suggested reporting criteria, this has improved but is still not uniformly applied. The prognostic factors included for evaluation varied from as few as three to seventeen, with over 50 studies using only univariate analysis. Individual papers reported much longer outcomes than others, but assessing the outcomes overall, there has been minimal change over the last 40 years. This supports the belief that novel approaches for lymphoma therapy will be required to substantively improve outcomes.

Efficacy and tolerability of a 12-week combination chemotherapy followed by lomustine consolidation treatment in canine B- and T-cell lymphoma

BACKGROUND

High-grade lymphoma in dogs is a chemotherapy-responsive neoplasia with remission rates exceeding 80% under combination chemotherapy protocols. Usually these protocols are intensive and 24 + weeks. The objective of the present study was to investigate if a shorter protocol combined with an oral lomustine maintenance treatment (3 × in 8 weeks) would present an acceptable result, both for B- and T-cell lymphomas, and for the different types of lymphomas normally encountered in private veterinary practice.

RESULTS

144 dogs entered the study. Lymphoma types included multicentric (n = 123), alimentary (n = 13), miscellaneous (n = 7), and mediastinal lymphoma (n = 1). Overall response rate was 83.3% (B-cell: 86.6%, T-cell: 79.4%). Complete remission (CR) was achieved in 72.2% (B-cell: 77.3%, T-cell: 67.6%) and partial remission (PR) in 11.1% (B-cell: 9.3%, T-cell: 11.8%) of the dogs. Median duration of first CR amounted to 242 days (B-cell: 263 d, T-cell: 161 d). Median survival in dogs with CR was 374 days (B-cell: 436 d, T-cell: 252 d), and median overall survival time was 291 days (B-cell: 357d, T-cell: 210d). Immunophenotype demonstrated an independent significant influence on duration of remission and survival in the whole group. Findings of splenic and hepatic cytology were not significant associated with patient outcome. Treatment was well tolerated; the majority of adverse events were classified as grade 1 or 2.

CONCLUSIONS

Short-term chemotherapy followed by lomustine consolidation leads to compara-ble remission and survival times compared to conventional protocols with cyclophosphamide, doxorubicin, vincristine and prednisolone with acceptable toxicosis in dogs with both B-cell and T-cell lymphoma.

Bacterial urinary tract infection and subclinical bacteriuria in dogs receiving antineoplastic chemotherapy

Background

Immunosuppressive treatment with glucocorticoids and cyclosporine increases the risk for positive urine cultures (PUCs) in dogs.

Objective

To investigate the prevalence and incidence of PUC in dogs diagnosed with cancer and treated with antineoplastic chemotherapy while distinguishing between subclinical bacteriuria (SB) and urinary tract infection (UTI).

Animals

Forty‐six client‐owned dogs with nonurogenital cancer treated with antineoplastic chemotherapy.

Methods

Prospective observational longitudinal clinical study. Dogs in which a urine culture was performed before the start of and at least once during antineoplastic chemotherapy were included. A McNemar's test was used to investigate if the prevalence of PUC increased during antineoplastic chemotherapy. Positive urine cultures were categorized into SB and UTI and multiple PUCs from the same dog and category were grouped together as 1 episode of PUC.

Results

Urine culture was positive in 21/185 urine samples in 8/46 dogs. Antineoplastic chemotherapy did not influence the prevalence of PUC (P = 1.00), which was 11% (5/46 dogs; 95% confidence interval: 5‐23%) before the start of and 13% (6/46 dogs; 95% confidence interval: 6‐26%) during antineoplastic chemotherapy. Eight dogs had 10 episodes of PUC; 7/10 episodes were classified as SB, and in 3/10 episodes UTI (chronic prostatitis, prostatic abscess, and emphysematous cystitis) was diagnosed. Escherichia coli was the most common pathogen, isolated in 9/10 episodes.

Conclusions and Clinical Importance

We did not find evidence that antineoplastic chemotherapy is a major predisposing factor for the development of PUC. Most dogs with PUC had SB.

Incidence of Sterile Hemorrhagic Cystitis in Dogs Treated with Cyclophosphamide and Low-Dose Furosemide

Cyclophosphamide is a commonly used chemotherapy in the treatment of lymphoma. It can cause sterile hemorrhagic cystitis (SHC), and furosemide is used to decrease the incidence of SHC. The aim of this study is to evaluate the incidence of SHC in dogs treated with a bolus maximum tolerated dose of oral cyclophosphamide and oral furosemide at a dose of 1 mg/kg. Medical records were reviewed to determine the incidence of SHC, dose and number of oral cyclophosphamide treatments, and the dose of furosemide. Other side effects from cyclophosphamide were also recorded. Eighty-one client-owned dogs that received a single oral maximum tolerated dose of cyclophosphamide concurrent with oral furosemide as part of a chemotherapy protocol for lymphoma were included in the study. A total of 252 doses of cyclophosphamide were administered to 81 dogs. The median dose of cyclophosphamide was 239.3 mg/m2. The median dose of furosemide was 1.08 mg/kg. SHC was suspected in 2 dogs (2.46%). Concurrent use of furosemide at a dose of 1 mg/kg with cyclophosphamide yields a similar incidence of SHC than using a higher dose of furosemide as previously reported.

Maintenance treatment in relapsed canine lymphoma after a short L-CHOP protocol

OBJECTIVE

A number of different rescue protocols for relapsed canine multicentric large-cell lymphoma have been described. The aim of this pilot study was to evaluate the efficacy of a maintenance treatment in dogs that experienced a second complete remission after a short L-CHOP-rescue protocol.

MATERIAL AND METHODS

Included in the study were dogs experiencing the first lymphoma relapse during a treatment-free period which were treated with a short L-CHOP protocol, achieved a complete remission and were afterwards treated with a continuous maintenance phase (MP) protocol. The L-CHOP protocol consisted of weekly treatments, with at least 3 additional treatments following complete remission. Thereafter the MP protocol with 2-week treatment intervals was conducted. It consisted of alternating oral home administration of different alkylating agents and one intravenously administered cytotoxic agent of a different mechanism of action. The dogs were presented either every 4 or 6 weeks for intravenous treatment and at this time a complete blood count was performed. The durations of the first remission, disease-free interval and overall survival time were evaluated.

RESULTS

A total of 20 dogs were included in the study. A median of 7 weekly applications were given before the treatment was switched to the MP protocol. During MP, 14 dogs were treated intravenously every 6 weeks and 6 dogs every 4 weeks. Haematological adverse events were mainly mild. During the L-CHOP-protocol, one septic event occurred, and 2 dogs were hospitalized due to gastrointestinal adverse events. No patient required hospitalization during the MP. Fifteen dogs completed at least one cycle in the MP and a median of 8.5 chemotherapeutic treatments were administered. The median disease-free interval was 264 days and the median overall survival time was 737 days.

CONCLUSION AND CLINICAL RELEVANCE

The protocol was generally well tolerated. Since 5 patients showed disease progression during the first cycle of the MP, dogs should ideally be evaluated for minimal residual disease before being switched to the MP. The case number in the presented study was low and the treatment relatively heterogeneous. Therefore, more dogs have to be treated with the proposed protocol before general recommendations can be made.

Treatment of feline intermediate- to high-grade lymphoma with a modified university of Wisconsin-Madison protocol: 119 cases (2004-2012)

CHOP-based (cyclophosphamide, doxorubicin, vinca alkaloid, prednisolone) chemotherapy protocols are often recommended for treatment of feline lymphoma. While maintenance-free CHOP-based protocols have been published and readily used in dogs, there is limited literature regarding similar maintenance-free protocols in cats. The purpose of this study was to describe the outcome of cats with intermediate- to high-grade lymphoma that were prescribed a modified 25-week University of Wisconsin-Madison (UW-25) chemotherapy protocol. A secondary objective was examination of potential prognostic factors. One hundred and nineteen cats from five institutions treated with a UW-25-based protocol were included. The Kaplan-Meier median progression-free interval (PFI) and survival time (MST) were 56 and 97 (range 2-2019) days, respectively. Cats assessed as having a complete response (CR) to therapy had significantly longer PFI and MST than those with partial or no response (PFI 205 versus 54 versus 21 days, respectively, P < 0.0001 and MST 318 versus 85 versus 27 days, respectively, P < 0.0001).

Phase I/II clinical trial of encapsulated, cytochrome P450 expressing cells as local activators of cyclophosphamide to treat spontaneous canine tumours

Based upon promising preclinical studies, a clinical trial was performed in which encapsulated cells overexpressing cytochrome P450 enzyme isoform 2B1 were implanted around malignant mammary tumours arising spontaneously in dogs. The dogs were then given cyclophosphamide, one of the standard chemotherapeutic agents used for the treatment of mammary tumours. The dogs were assessed for a number of clinical parameters as well as for reduction in tumour size. The treatment was well tolerated with no evidence of adverse reactions or side effects being associated with the administration of the encapsulated cells. Reductions in tumour size of more than 50% were observed for 6 out of the 11 tumours analysed while 5 tumours showing minor responses, i.e. stable disease. In contrast, the tumours that received cyclophosphamide alone showed only stable disease. Taken together, this data suggests that encapsulated cytochrome P450 expressing cells combined with chemotherapy may be useful in the local treatment of a number of dog mammary tumours and support the performance of further clinical studies to evaluate this new treatment.