Cushing’s syndrome: drug targets and therapeutic options

Cushing's disease in dogs: cabergoline treatment

The treatment of pituitary-dependent hyperadrenocorticism (PDH) in dogs has for a long time been focused on inhibiting the adrenal gland using drugs such as o-p'-DDD, Ketoconazole and Trilostane, without attacking the primary cause: the corticotrophinoma. Corticotroph cells can express the D2 dopaminergic receptor; therefore cabergoline (Cbg) could be effective as a treatment. Follow-up over 4 years was carried out in 40 dogs with PDH that were treated with Cbg (0.07 mg/kg/week. Out of the 40 dogs, 17 responded to Cbg (42.5%). A year after the treatment, there was a significant decrease in ACTH (p<0.0001), alpha-MSH (p<0.01), urinary cortisol/creatinine ratio (p<0.001), and of the tumor size (p<0.0001) evaluated by nuclear magnetic resonance. Dogs responding to Cbg lived significantly longer (p<0.001) than those in the control group. To conclude, Cbg is useful in 42.5% of dogs with PDH, justifying its use as a treatment.

An orally active corticotropin releasing factor 1 receptor antagonist from 8-aryl-1,3a,7,8-tetraaza-cyclopenta[a]indenes

8-Aryl-1,3a,7,8-tetraaza-cyclopenta[a]indenes represent a novel series of high-affinity corticotropin-releasing factor-1 receptor (CRF1R) antagonists. Herein we report the synthesis and SAR around the tricyclic core and the anxiolytic activity of an orally dosed exemplary compound 9d (K(i)=8.0 nM) in a mouse canopy model.

Synthesis and structure–activity relationship of imidazo[1,2-a]benzimidazoles as corticotropin-releasing factor 1 receptor antagonists

8-Aryl-1,3a,8-triaza-cyclopenta[a]indenes represent a novel series of high binding affinity corticotropin-releasing factor 1 receptor antagonists. Here, we report their synthesis, SAR, and pharmacokinetic properties of compound 8e (K(i) = 23 nM).

Update on the medical management of pituitary adenomas

The medical treatment of pituitary adenomas has changed significantly over the past decade. Pharmacologic therapy for prolactinomas in the form of dopamine agonists has been available since the 1970s, and somatostatin analogues for treatment of growth hormone (GH)-secreting adenomas were introduced in the 1980s. However, the recent introduction of long-acting forms of these agents has markedly improved efficacy. Furthermore, long-acting somatostatin analogues also have utility in treating thyrotropin adenomas and a subset of adrenocorticotroph tumors. Limited clinical studies with long-acting dopamine agonists suggest that a subset of patients with GH, adrenocorticotroph, and gonadotropin/nonsecreting adenomas may also benefit from therapy with these agents. The introduction of a GH receptor antagonist in the 1990s has added to the pharmacologic armamentarium for treatment of acromegaly. In parallel with improved medical therapy, hormonal assays for assessing tumor activity have improved in sensitivity, necessitating new standards for treatment optimization. This article highlights some of these evolving new ideas and approaches to the pharmacologic management of pituitary adenomas.