Cabergoline is a dopamine 2 receptor (D2R) agonist which is a second line medical therapy for human acromegalic patients. Pasireotide, a somatostatin analogue, is the only effective medical management option for feline acromegaly but its cost is a limiting factor for many owners. Our work has demonstrated dopamine receptors within the feline acromegalic pituitary and we hypothesised that cabergoline would improve diabetic control and IGF-1 concentrations of diabetic acromegalic cats.

This was a prospective cohort study of client-owned diabetic acromegalic cats, Ethics approval URN 2016 1604. Enrolment criteria were: a diagnosis of diabetes mellitus, an IGF-1 concentration >1000 ng/ml and owners declining alternative treatment options for acromegaly. Patients were admitted to the hospital on day 0, underwent pituitary imaging and started cabergoline therapy (Kelactin, Kela N.V.) on day 1. Cats were monitored in hospital until day 4 and were discharged to continue treatment at home. Serum IGF-1 and fructosamine were measured on day 0, day 4 and month 1. Any possible medication side effects were recorded. Descriptive statistics and non-parametric tests were used to analyse the data.

Six cats were enrolled. The first three cats received 5 µg/kg q24h PO and the second three cats received 10 µg/kg q24h PO of cabergoline. The median IGF-1 concentration at day 0 was 1797 ng/ml (range 890–>2000) which was not statistically different to day 4 and month 1 (1884 ng/ml and 1754 ng/ml, respectively). The median fructosamine concentration on day 0 was 551 μmol/l (range 454–887) which was not statistically different from day 4 and month 1 (551 to 569, respectively). All cats were receiving PZI insulin (ProZinc, Boehringer) and the median dose on day 0 (1.1 units/kg q12h) was not different to day 4 and month 1 (1.1 and 1.2, respectively). Three patients experienced a single gastrointestinal upset event (inappetence, diarrhoea) which resolved within three days. One of the six cats experienced an improvement of diabetic control (fructosamine day 0 was 454 μmol/l and month 1 was 288 μmol/l while insulin dose on day 0 was 1 unit/kg q12h and month 1 was 0.2 units/kg q12h) although there was no decrease of IGF-1 concentration (day 0: 890 ng/ml; month 1:929 ng/ml).

Cabergoline therapy, using the investigated dose and duration, was not associated with a reduction in IGF-1 concentration in the tested diabetic acromegalic cats; glycaemic control improved in one. Additional cases, alternative dosing regimens and longer-term follow-up are being assessed.

Disclosures

Disclosures to report:

The diabetic remission clinic is supported by Nestle Purina and Boehringer Ingelheim.