Baseline tumor gene expression signatures correlate with chemoimmunotherapy treatment responsiveness in canine B cell lymphoma

Abstract

Pet dogs develop spontaneous diffuse large B cell lymphoma (DLBCL), and veterinary clinical trials have been employed to treat canine DLBCL and to inform clinical trials for their human companions. A challenge that remains is selection of treatment to improve outcomes. The dogs in this study were part of a larger clinical trial evaluating the use of combinations of doxorubicin chemotherapy, anti-CD20 monoclonal antibody, and one of three small molecule inhibitors: KPT-9274, TAK-981, or RV1001. We hypothesized that significant differential expression of genes (DEGs) in the tumors at baseline could help predict which dogs would respond better to each treatment based on the molecular pathways targeted by each drug. To this end, we evaluated gene expression in lymph node aspirates from 18 trial dogs using the NanoString nCounter Canine Immuno-oncology (IO) Panel. We defined good responders as those who relapsed after 90 days, and poor responders as those who relapsed prior to 90 days. We analyzed all dogs at baseline and compared poor responders to good responders, and found increased CCND3 correlated with poor prognosis and increased CD36 correlated with good prognosis, as is observed in humans. There was minimal DEG overlap between treatment arms, prompting separate analyses for each treatment cohort. Increased CREBBP and CDKN1A for KPT-9274, increased TLR3 for TAK-981, and increased PI3Kδ, AKT3, and PTEN, and decreased NRAS for RV1001 were associated with better prognoses. Trends for selected candidate biomarker genes were confirmed via qPCR. Our findings emphasize the heterogeneity in DLBCL, similarities and differences between canine and human DLBCL, and ultimately identify biomarkers that may help guide the choice of chemoimmunotherapy treatment in dogs.

Safety and biologic activity of a canine anti‐CD20 monoclonal antibody in dogs with diffuse large B‐cell lymphoma

“…It is likely that the small sample size per cohort and use of several different immunomodulatory drugs in combination made it challenging to explicitly link the use of 1E4‐cIgGB to progression free survival (PFS) and OST. In support of this, we have recently demonstrated that baseline tumor gene expression was linked to response and outcome to the chemoimmunotherapy protocols used to treat dogs with DLBCL in this study 24 . Specific associations included increased expression of CREBBP and CDKN1A for response to KPT‐9274, increased TLR3 for response to TAK‐981, and increased PI3Kδ , AKT3 , and PTEN , and decreased NRAS for response to RV1001 24 .…”

“…All dogs received 1E4‐cIgGB, the canine chimeric monoclonal anti‐CD20 antibody, 20 along with varying combinations of doxorubicin and immunomodulatory study medications defined by the study cohort (Table 1) and detailed in a previous publication 24 . The antibody was supplied by Elanco Animal Health as a 30.7 mg/mL solution and stored at 4°C.…”

“…The TAK‐981 was diluted in 0.9% NaCl to 1.8‐2.0 mg/mL and administered over 30 minutes. Additional information regarding immunomodulatory study medications used in this study and their mechanisms of action is provided in Table S1 and is detailed elsewhere 24 . Doxorubicin was supplied as a 2 mg/mL solution and was administered at a dose of 20‐25 mg/m 2 , or 0.8‐0.9 mg/kg for dogs 10 kg or less.…”

“…All dogs received 1E4-cIgGB, the canine chimeric monoclonal anti-CD20 antibody, 20 along with varying combinations of doxorubicin and immunomodulatory study medications defined by the study cohort (Table 1) and detailed in a previous publication. 24 The antibody was supplied by Elanco Animal Health as a 30.7 mg/mL solution and stored at 4 C. Before administration, dogs were administered diphenhydramine (2 mg/kg SC) and dexamethasone sodium phosphate (0.2 mg/kg IV) to prevent possible infusion related reactions as these are a well-established complication associated with rituximab administration and a similar premedication strategy is employed in humans. 25 The antibody was diluted to 4 mg/mL in 0.9% NaCl before IV administration over 90 minutes.…”

“…Additional information regarding immunomodulatory study medications used in this study and their mechanisms of action is provided in Table S1 and is detailed elsewhere. 24 Doxorubicin was supplied as a 2 mg/mL solution and was administered at a dose of 20-25 mg/m 2 , or 0.8-0.9 mg/kg for dogs 10 kg or less. The dose was set intentionally low as part of the chemotherapy-light regimen designed to mitigate cytotoxic drug toxicosis by leveraging unique combinations of immunomodulatory agents.…”