Development of prednisone resistance in naïve canine lymphoma: Longitudinal evaluation of NR3C1α, ABCB1, and 11β-HSD mRNA expression

Pilot Study of a Novel First-Line Protocol (THOP) for Intermediate-Large B-Cell Lymphoma in Dogs

The current standard of care for treatment of intermediate-large B-cell lymphoma in dogs is a CHOP-based chemotherapy protocol. On-protocol disease progression is reported to be temporally associated with cyclophosphamide administration. The objectives of this prospective pilot clinical trial were to describe the adverse event profile and identify early signal of efficacy of a novel cyclophosphamide-free chemotherapy protocol consisting of temozolomide, doxorubicin, vincristine, and prednisone (THOP) as first-line treatment in dogs with diffuse large cell B-cell lymphoma. Treatment-naïve dogs with intermediate-large B-cell lymphoma were enrolled. THOP was administered as a three-week cycle for five cycles. Fourteen dogs were enrolled. All dogs achieved complete remission with a median time to progression (TTP) of 269 days and a median survival of 433 days. There were five grade III and four grade IV hematologic toxicities reported; one grade III gastrointestinal toxicity was observed. THOP appears to be well tolerated and an effective first-line protocol for the treatment of intermediate-large B-cell lymphoma in dogs.

Pharmacology of drugs used in autoimmune dermatopathies in cats and dogs: A narrative review

Immunosuppressive drugs are the mainstay of treatment for many feline and canine autoimmune skin diseases, either as monotherapy or in combination with other drugs. Treatment with these drugs is often lifelong and may have long-term consequences on the affected animal's overall quality-of-life. Clinicians need to understand the pharmacology of immunosuppressants in planning and executing the treatment regimen for the best possible clinical outcome, as well as reducing the risk of adverse effects. This review paper will focus on the mechanism of action, pharmacokinetics and pharmacodynamics, clinical uses and adverse effects of immunosuppressive drugs used to treat autoimmune dermatoses in cats and dogs. These include glucocorticoids, ciclosporin A, azathioprine, chlorambucil, mycophenolate mofetil, oclacitinib and Bruton's tyrosine kinase inhibitors.

Evaluation of clinical response and prognostic factors in canine multicentric lymphoma treated with first rescue therapy

Despite an initial strong response in most dogs with multicentric lymphoma treated with chemotherapy, relapse remains common. There is no clearly superior first rescue protocol described either for resistant or relapsed canine multicentric lymphoma. The objectives of this study were to assess clinical response and outcomes for canine multicentric lymphoma treated with first rescue protocols. The secondary objective was to assess prognostic variables for dogs undergoing these protocols. This was a bi-institutional retrospective cohort study. Two hundred and sixty-five dogs were treated with first rescue chemotherapy, including anthracycline-based combination chemotherapy (CHOP-like, n = 50), nitrosourea alkylating agent-rich chemotherapy (n = 45), anthracycline-based or related compound chemotherapy (n = 34), or nitrosourea single-agent chemotherapy (n = 136). The overall median progression free survival time of first rescue protocol was 56.0 days (0-455 days). Important prognostic factors identified for first rescue protocol included the attainment of a complete response to the first rescue chemotherapy (p < .001), the use of a CHOP-like first rescue protocol (p = .009), duration of first remission (HR 0.997, p = .028), and if prednisolone was included in the first rescue protocol (HR 0.41, p = .003). Adverse events (AE) were common, with 81.1% of dogs experiencing at least one AE during first rescue chemotherapy. This study highlights the need for improved first rescue therapies to provide durable remission in canine resistant or relapsed lymphoma.

Comparison of chemotherapy outcomes between normal and high serum cortisol concentration in dogs with lymphoma

BACKGROUND

Increased serum cortisol (COR) concentrations may induce glucocorticoid resistance by down-regulation of glucocorticoid receptor (GCR), resulting in decreased chemotherapy efficacy in dogs with lymphoma.

HYPOTHESIS

Investigate the relationship between serum COR concentrations and chemotherapy outcomes in dogs with lymphoma.

ANIMALS

Thirty client-owned dogs with lymphoma, with serum COR concentration measured using serum samples collected at diagnosis.

METHODS

Retrospective study. Dogs were divided into 2 groups based on serum COR concentrations: a normal group (n = 16) with COR concentrations <6 μg/dL and a high group (14) with COR concentrations ≥6 μg/dL. We compared signalment, clinical signs, stage, type of lymphoma, adrenal gland size, alkaline phosphatase (ALP) activity, response to chemotherapy, progression-free survival (PFS), overall survival (OS), and rate of P-glycoprotein (P-gp)- and GCR-positive cells between the 2 groups.

RESULTS

No significant differences were found in the demographic characteristics between the 2 groups. However, the high COR group exhibited a significantly lower response to chemotherapy, PFS, and OS compared with the normal COR group. Serum ALP activity was significantly higher in the high COR group than in the normal COR group. Adrenal gland size was also significantly larger in the high COR group. Although no significant differences were found in the rate of P-gp-positive cells between the 2 groups, the rate of GCR-positive cells was significantly lower in the high COR group.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our data suggests that measurement of serum COR concentrations may serve as a potential prognostic factor and evaluation index.

Survival time for dogs with previously untreated, peripheral nodal, intermediate- or large-cell lymphoma treated with prednisone alone: the Canine Lymphoma Steroid Only trial

OBJECTIVE

To evaluate survival times for dogs with previously untreated, peripheral nodal, intermediate- or large-cell lymphoma treated with prednisone alone.

ANIMALS

109 client-owned dogs recruited from 15 institutions in the United States.

PROCEDURES

Dogs were treated with prednisone at a dosage of 40 mg/m², PO, once daily for 7 days and at a dosage of 20 mg/m², PO, once daily thereafter. Quality of life (QOL) was assessed by owners with a visual analog scale when treatment was started (day 0), 1 and 2 weeks after treatment was started, and every 4 weeks thereafter. The primary outcome of interest was survival time as determined by the Kaplan-Meier method. Factors potentially associated with survival time were examined.

RESULTS

Median overall survival time was 50 days (95% CI, 41 to 59 days). Factors associated with survival time included substage (a vs b) and immunophenotype (B cell vs T cell). Owner-assigned QOL scores on days 0 and 14 were significantly positively correlated with survival time. When QOL score was dichotomized, dogs with day 0 or day 14 QOL scores ≥ 50 had significantly longer survival times, compared with dogs with day 0 or day 14 QOL scores < 50. No variables were predictive of long-term (> 120 days) survival.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that survival times were short for dogs with previously untreated, peripheral nodal, intermediate- or large-cell lymphoma treated with prednisone alone. Owner-perceived QOL and clinician-assigned substage were both associated with survival time. Findings provide potentially important information for clinicians to discuss with owners of dogs with lymphoma at the time treatment decisions are made.