Multicentre, retrospective study to assess long-term outcomes of chelator based treatment with trientine in Wilson disease patients withdrawn from therapy with d -penicillamine.

OBJECTIVES: Trientine dihydrochloride (TETA-2HCl) has been used for the treatment of Wilson disease for over 30 years. The current study was designed to systematically evaluate existing data to further define the long-term outcome of the efficacy and tolerability of TETA-2HCl in Wilson disease patients. METHODS: Medical records of 77 Wilson disease patients were reviewed to collect data on hepatic and neurologic symptoms, copper (Cu) homeostasis and adverse events. Data were collected for 48 months after initiation of TETA-2HCl after withdrawal of D-penicillamine treatment. RESULTS: Mean duration of TETA-2HCl treatment was 8 years (range 5 months-32.5 years). Over the course of TETA-2HCl treatment, 35% of patients had no hepatic symptoms whereas in 49.4% of patients, hepatic symptoms improved. They remained unchanged in 10.4% of patients and worsened in 5.2% of patients. No patients progressed to acute hepatic failure or necessity of a liver transplant. During TETA-2HCl treatment, 46.7% of patients had no neurologic symptoms; in 14.3% of patients, neurologic symptoms improved whereas in 36.4% of patients, they remained stable and worsened in 2.6% of patients. During the evaluation period, 12 patients discontinued TETA-2HCl treatment due to: anemia ( N = 1), inadequate hepatic response ( N = 2), switch to zinc treatment ( N = 8) and patient's decision to withdraw from treatment ( N = 1). Treatment-emergent adverse events were reported by 24.7% of the patients of which gastrointestinal disorders (9.1%) and nervous system disorders (5.2%) were most reported. CONCLUSIONS: TETA-2HCl is well-tolerated and effective in Wilson disease patients following the withdrawal of treatment with D-penicillamine. ClinicalTrials.govIdentifier : NCT02426905.

Characterization and small-molecule stabilization of the multisite tandem binding between 14-3-3 and the R domain of CFTR.

Cystic fibrosis is a fatal genetic disease, most frequently caused by the retention of the CFTR (cystic fibrosis transmembrane conductance regulator) mutant protein in the endoplasmic reticulum (ER). The binding of the 14-3-3 protein to the CFTR regulatory (R) domain has been found to enhance CFTR trafficking to the plasma membrane. To define the mechanism of action of this protein-protein interaction, we have examined the interaction in vitro. The disordered multiphosphorylated R domain contains nine different 14-3-3 binding motifs. Furthermore, the 14-3-3 protein forms a dimer containing two amphipathic grooves that can potentially bind these phosphorylated motifs. This results in a number of possible binding mechanisms between these two proteins. Using multiple biochemical assays and crystal structures, we show that the interaction between them is governed by two binding sites: The key binding site of CFTR (pS768) occupies one groove of the 14-3-3 dimer, and a weaker, secondary binding site occupies the other binding groove. We show that fusicoccin-A, a natural-product tool compound used in studies of 14-3-3 biology, can stabilize the interaction between 14-3-3 and CFTR by selectively interacting with a secondary binding motif of CFTR (pS753). The stabilization of this interaction stimulates the trafficking of mutant CFTR to the plasma membrane. This definition of the druggability of the 14-3-3-CFTR interface might offer an approach for cystic fibrosis therapeutics.