SAT0260 PENTOXYFILLINE GEL FOR ORAL ULCERS IN PATIENTS WITH BEHÇET’S SYNDROME

Background:

Oral ulcers, the hallmark lesion of Behçet’s syndrome (BS) can be disabling and impair eating, drinking and speaking. Despite recent advances in systemic medications for the treatment of oral ulcers, some patients do not achieve complete remission. Topical agents may help such patients by decreasing the pain and duration of oral ulcers. Pentoxyfilline (PTX) is a methylxanthine derivative that inhibits phosphodiesterase and is thought to have immunomodulatory effects in addition to improving blood flow which is its main reason for use in peripheral vascular disorders.

Objectives:

The aim of this study is to assess the efficacy and safety of PTX gel for oral ulcers in patients with BS. We also aimed to explore the best tools for the assessment of treatment response to topical agents in randomized controlled trials (Clinicaltrial.gov ID: NCT 03888846).

Methods:

This was an open-label, randomized, parallel group study comparing PTX gel in addition to colchicine (PTX-COL) with colchicine alone (COL). Patients with BS who were treated with colchicine and not using any other systemic medications for BS, having at least one oral ulcer that appeared during the last 48 hours were included. PTX 5% gel with a dose of 1000 mg/day was applied in 4 divided doses per day for 14 days. Patients were contacted daily for 14 consecutive days. Photographs were taken every 24 - 48 hours and graphical processing software was used to calculate the area of the index ulcer. Duration of the index ulcer, time to start of index ulcer shrinkage, time to 50% reduction in oral ulcer pain on a 10 mm visual analog scale (VAS), change from baseline in the area of the index ulcer over time, total number of oral ulcers and adverse events were evaluated.

Results:

A total of 41 patients were randomized, 39 patients (18 in the PTX-COL group and 21 in the COL group) completed the study and 2 patients in PTX-COL group withdrew from the study due to unacceptable dysgeusia and nausea. Mean duration of index ulcer, time to start of index ulcer shrinkage, time to 50% reduction in oral ulcer pain, and number of patients with no detectable ulcers on day 4 in each group were lower in the PTX-COL group as presented in the Table. Change from baseline in the area of index ulcer and pain score over time is shown in the Figure. There were no serious adverse events. Fifteen (75%) patients reported nausea, 11 (55%) reported dysgeusia and 2 reported vomitting in the PTX-COL group, while 2 patients (10%) reported nausea in the COL group.

Conclusion:

This pilot phase 2 open label, randomized controlled study supports the hypothesis that topical PTX in addition to colchicine accelerates the healing of BS oral ulcers compared to colchicine alone. A phase 3 controlled study with a higher number of patients is planned with improving the taste for tolerability of the product.

Disclosure of Interests:

Gulen Hatemi Grant/research support from: BMS, Celgene Corporation, Silk Road Therapeutics – grant/research support, Consultant of: Bayer, Eli Lilly – consultant, Speakers bureau: AbbVie, Mustafa Nevzat, Novartis, UCB – speaker, Berna Yurttas: None declared, Zekayi Kutlubay: None declared, Tim Cote Employee of: Silk Road Therapeutics is in Washington, DC, USA, Şemsi Burak Derkunt Employee of: Silk Road Therapeutics is in Washington, DC, USA, Yusuf Yazici: None declared, Hasan Yazici: None declared

Opioid-induced increase in [Ca2+]i in ND8-47 neuroblastoma x dorsal root ganglion hybrid cells is mediated through G protein-coupled delta-opioid receptors and desensitized by chronic exposure to opioid

delta-Receptor agonists induce a concentration-dependent increase in intracellular calcium concentration ([Ca2+]i) in ND8-47 cells by activating dihydropyridine-sensitive Ca2+ channels. The role of G proteins in transducing the opioid effect has been studied. Pretreatment of cells with pertussis toxin (100 ng/ml, 24 h) almost completely blocked [D-Ser2,Leu5]enkephalin-Thr (DSLET)-induced increase in [Ca2+]i. Cholera toxin (10 nM, 24 h) had no effect on DSLET-induced response. Pretreatment of the cells with 1 microM DSLET for 1 h resulted in a 30% inhibition of DSLET-induced increase in [Ca2+]i and a 78% inhibition after exposure for 24 h. After 1 h of exposure to DSLET, there was a decrease in agonist affinity with no significant changes in receptor density. Cells exposed to 1 microM DSLET for 24 h demonstrate a nearly 90% decrease in [3H]diprenorphine binding, with a decrease in affinity for agonist at the remaining binding sites. G protein subunits alpha i2, alpha i3, alpha s, and alpha q were detected in ND8-47 cell membranes by western blot; alpha o and alpha i1 were not present. Chronic DSLET treatment had no significant effect on the quantity of each of the alpha-subunits. These results suggest that the DSLET-induced increase in [Ca2+]i mediated through pertussis toxin-sensitive G proteins (probably Gi2 or Gi3) and the attenuation of this response in chronically treated cells is associated with a relatively rapid reduction in receptor affinity to DSLET and a slow reduction in receptor density.

Biochemical identification of the beta-adrenoceptor and evidence for the involvement of an adenosine 3',5'-monophosphate system in the beta-adrenergically induced release of alph-melanocyte-stimulating hormone in the intermediate lobe of the rat pituitary gland

The beta-adrenoceptor in the intermediate lobe (IL) of the hypophysis of the rat is characterized on the basis of the following: 1) the ability of beta-adrenergic agonists to increase adenylate cyclase activity in homogenates of the IL, and 2) the ability of drugs active upon the beta-adrenoceptor to compete with [125I]hydroxybenzylpindolol, a radiolabeled beta-adrenergic antagonist, for high affinity (Kd = 232 pM) binding sites. The values of the affinity of the beta-adrenoceptor for drugs obtained in either assay system are in good agreement. The relative potency among agonists, L-isoproterenol greater than L-epinephrine greater than L-norepinephrine, suggests that the receptor is of the beta-2 subcategory. cAMP, derivatives of cAMP, and a phosphodiesterase inhibitor, theophylline, mimic the ability of l-isoproterenol to enhance the release of alpha MSH from dispersed cells of the rat IL. The present results are in accord with the possibility that occupancy by agonists of the beta-adrenoceptor of the IL enhances adenylate cyclase activity, resulting in an accumulation of cAMP which initiates the intracellular events that are ultimately expressed as an enhanced release of alpha MSH. Pharmacological data suggest that stimulation of a dopamine receptor in the IL diminishes the response of the beta-adrenoceptor to agonists.

Lisuride hydrogen maleate: an ergoline with beta-adrenergic antagonist activity

Lisuride hydrogen maleate is identified as a potent beta-adrenergic antagonist using a hormone-sensitive adenylate cyclase system and [3H]dihydroalprenolol binding in cell free homogenates of rabbit cerebellum. Lisuride and two other ergolines, lergotrile and bromocriptine, and the phenothiazine, fluphenazine, all interact with spiroperidol binding sites (dopamine receptors) in the anterior pituitary; however, among these compounds lisuride is unique in its ability to antagonize the beta-adrenoceptor.