Risk factors for development of sterile haemorrhagic cystitis in canine lymphoma patients receiving oral cyclophosphamide: a case-control study

Individualized chemotherapy drug dose escalation in dogs with multicentric lymphoma

BACKGROUND

This study was performed to determine the ability to escalate drug doses in a 15-week CHOP protocol in dogs with multicentric lymphoma.

HYPOTHESIS

We hypothesized that at least 50% of dogs could successfully be escalated in at least 1 drug. Secondary aims were to establish objective response rate (ORR), progression-free interval (PFI), and overall survival time (OST).

ANIMALS

Thirty dogs with newly diagnosed multicentric lymphoma were prospectively treated with a 15-week CHOP protocol.

METHODS

This was a prospective cohort study. Drug doses that did not cause dose-limiting adverse effects (AEs) were increased using a standardized escalation protocol. AEs and response were assessed using VCOG criteria. Serial blood samples were collected after the first dose of each drug for pharmacokinetic analysis.

RESULTS

Of the 23 dogs with the opportunity to dose escalate, at least 1 drug was successfully escalated in 18 (78%). Vincristine was successfully escalated to 0.8 mg/m2 or higher in 11 dogs, cyclophosphamide to 300 mg/m2 or higher in 16 dogs, and doxorubicin to 35 mg/m2 or 1.4 mg/kg or higher in 9 dogs. Three of the 23 dogs (13%) were hospitalized at least once because of drug-induced AEs. Neutropenia was the most common dose-limiting toxicosis for all drugs. Peak doxorubicin concentrations were significantly lower in dogs where doxorubicin was successfully escalated. The objective response rate was 100%. The median progression free interval was 171 days. The median overall survival time was 254 days.

CONCLUSIONS

Drugs in the CHOP protocol can often be escalated safely with manageable AEs.

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.

Outcome of Canine Multicentric Lymphoma after Single or Divided Treatment with Cyclophosphamide in Multidrug Chemotherapy

Cyclophosphamide is commonly used in combination chemotherapy to treat dogs with lymphoma. The metabolite of cyclophosphamide, acrolein, can irritate urinary bladder and cause sterile hemorrhagic cystitis. Dividing the administration of cyclophosphamide across multiple days may reduce the concentration of this metabolite in urinary bladder and reduce the possibility of cystitis. However, the impact of the therapeutic effect of this modification is not evaluated and compared to traditional single maximum-tolerated dose regimen. Seventy-two dogs with multicentric lymphoma received either bolus doses or divided doses of cyclophosphamide were included in this study. The incidence of hemorrhagic cystitis between 2 cyclophosphamide treatment groups was not significantly different (P = .357). There was no statistical difference in progression-free survival and survival time between 2 groups (P = .267 and P = .346). This modification of cyclophosphamide administration did not reduce the side effect of cystitis or affect remission and survival times in lymphoma dogs.

Synthesis, quality control, and bio-evaluation of 99m Tc-cyclophosphamide

Cancer is found to be the leading cause of death worldwide characterized by uncontrolled cell division. Nuclear medicines imaging using radiopharmaceuticals have pronounced potential for the diagnosis and treatment of cancers. Cyclophosphamide (CPH) is an antineoplastic drug which targets selectively cancer cells. In the present work, labeling of CPH with Tc-99m is performed for diagnostic purpose, which gave labeling yield as high as 99% using 20 μg SnCl₂ ·2H₂ O, 200 μg of ligand at pH 7 for 10 min reaction time at room temperature. The characterization of the prepared complex was performed using ITLC, electrophoresis, and HPLC. In vitro stability was analyzed in the presence of human serum at 37°C which has maximum value of 94 ± 0.5. The biodistribution studies of ^99m Tc-CPH were performed in normal and tumor bearing Swiss Webster mice. The high accumulation of ^99m Tc-CPH was observed in liver and tumours respectively at 4 hr after injection. Biodistribution results revealed that ^99m Tc-CPH may be a potential tumour diagnostic agent simultaneously with chemotherapy.

Adjuvant Doxorubicin with or without Metronomic Cyclophosphamide for Canine Splenic Hemangiosarcoma

This retrospective study investigated the outcome of 33 dogs with splenic hemangiosarcoma treated with surgery followed by adjuvant dose-intensified doxorubicin (DOX) with or without low-dose metronomic cyclophosphamide (LDM-C) maintenance therapy. Among the 33 dogs, 18 dogs received LDM-C. Clinical stage was available for all dogs (5 stage I, 18 stage II, and 10 stage III). Nine dogs had macroscopic, and 24 dogs had microscopic disease at the start of DOX treatment. Median progression-free survival (PFS) and overall survival were 125 and 133 days, respectively. Clinical stage and tumor burden (microscopic versus macroscopic) at the start of chemotherapy was prognostic for PFS. No significant difference was observed in PFS or overall survival for the addition of LDM-C after a completed DOX protocol (P = .563 and P = .148, respectively). Based on the results of this retrospective study, the addition of LDM-C therapy as a maintenance regimen following a completed protocol of DOX adjuvant treatment of canine hemangiosarcoma may not improve outcome.

Impact of Toceranib/Piroxicam/Cyclophosphamide Maintenance Therapy on Outcome of Dogs with Appendicular Osteosarcoma following Amputation and Carboplatin Chemotherapy: A Multi-Institutional Study

Background

We hypothesized that the addition of toceranib to metronomic cyclophosphamide/piroxicam therapy would significantly improve disease-free interval (DFI) and overall survival (OS) in dogs with appendicular osteosarcoma (OSA) following amputation and carboplatin chemotherapy.

Methods and Findings

This was a randomized, prospective clinical trial in which dogs with OSA free of gross metastatic disease (n = 126) received carboplatin chemotherapy (4 doses) following amputation. On study entry, dogs were randomized to receive piroxicam/cyclophosphamide with or without toceranib (n = 63 each) after completing chemotherapy. Patient demographics were not significantly different between both groups. During or immediately following carboplatin chemotherapy, 32 dogs (n = 13 toceranib; n = 19 control) developed metastatic disease, and 13 dogs left the study due to other medical conditions or owner preference. Following carboplatin chemotherapy, 81 dogs (n = 46 toceranib; n = 35 control) received the metronomic treatment; 35 dogs (n = 20 toceranib; n = 15 control) developed metastatic disease during the maintenance therapy, and 26 dogs left the study due to other medical conditions or owner preference. Nine toceranib-treated and 11 control dogs completed the study without evidence of metastatic disease 1-year following amputation. Toceranib-treated dogs experienced more episodes of diarrhea, neutropenia and weight loss than control dogs, although these toxicities were low-grade and typically resolved with supportive care. More toceranib-treated dogs (n = 8) were removed from the study for therapy-associated adverse events compared to control dogs (n = 1). The median DFI for control and toceranib treated dogs was 215 and 233 days, respectively (p = 0.274); the median OS for control and toceranib treated dogs was 242 and 318 days, respectively (p = 0.08). The one year survival rate for control dogs was 35% compared to 38% for dogs receiving toceranib.

Conclusions

The addition of toceranib to metronomic piroxicam/cyclophosphamide therapy following amputation and carboplatin chemotherapy did not improve median DFI, OS or the 1-year survival rate in dogs with OSA.