Effects of cyclosporine treatment on supranormal feline serum pancreatic lipase immunoreactivity concentrations

Chronic pancreatitis (CP) is a common disease in middle‐aged to older cats. Treatment with corticosteroids has been suggested, but clinical data on efficacy is lacking. In a study in mice, cyclosporine treatment significantly reduced the severity of experimentally‐induced autoimmune pancreatitis. Thus, cyclosporine is an interesting treatment option in feline CP. The aim of this retrospective study was to evaluate the efficacy of cyclosporine on supranormal serum specific feline pancreatic lipase immunoreactivity (s‐Spec fPL) concentrations in cats with suspected CP treated at Evidensia Specialist Animal Hospital Helsingborg, Sweden, during 2013‐2019. Inclusion criteria were a history and clinical findings suggestive of CP, s‐Spec fPL concentrations above 5.4 mg/L (reference 0‐3.5 mg/L) on at least two occasions and treatment with cyclosporine for at least three weeks. Exclusion criteria were incomplete clinical records. Spec fPL was analyzed at Idexx Laboratories, Ludwigsburg, Germany. Nineteen cats aged 6.9‐17.5 years (median 11.6) were included. The most common breed was Domestic Short Hair (n = 10). Sixteen cats were neutered males (84%) and three neutered females. Chronic enteropathy was confirmed with histopathology in 6/19 cats. In nine additional cats, chronic enteropathy was suspected based on ultrasonography and/or hypocobalaminemia. Other comorbidities were common, including but not limited to, hepatobiliary disease (n = 15) and diabetes mellitus (n = 7). Ultrasonography of the pancreas was performed in 18 cats. 13/18 had an ultrasonographically abnormal pancreas. Pancreatic biopsies were not collected from any of the cats. Median (range) s‐Spec fPL concentration at baseline was 14.2 mg/L (6.1‐43.3) and 6.7 mg/L (0.9‐23.6) at follow‐up. Cyclosporine treatment (5.0‐7.9 mg/kg orally SID) was associated with a significant reduction in s‐Spec fPL concentrations (P = 0.0008) at follow‐up after 23‐206 days (median 35) compared with baseline. In three cats, no reduction in s‐Spec fPL concentrations occurred. In cats responding to cyclosporine, dose tapering (n=7) or withdrawal (n = 4) was associated with a significant increase in s‐Spec fPL concentrations from median 4.5 mg/L (1.5‐8.8) to 9.3 mg/L (2.1‐27.0) (P=0.012). Adverse effects were reported for 12 cats. The most common was hypersalivation and poor drug palatability (n=6). This study has several limitations, including unstandardized treatment length and dose, no control group and lack of pancreatic biopsies. Despite the limitations, our results suggest that cyclosporine treatment reduces supranormal s‐Spec fPL concentrations in cats with CP and dose reduction can lead to increasing s‐Spec fPL concentrations. Future studies are warranted to investigate the effect of cyclosporine on chronic pancreatic inflammation and clinical outcome of cats with confirmed CP.