Abstract

Wilson disease (WD) is a rare genetic disorder that can progress to either acute or chronic liver diseases due to excess copper accumulation in the liver derived from disruptive mutations affecting the ATP7B gene with consequent copper metabolism and trafficking disturbances. In current clinical practice, reduction of excess liver copper and amelioration of the subsequent liver pathology by the approved copper chelators is often inadequate. Our recent reports showed the potential of ARBM-101 as a drug candidate that promptly removes excess copper by increasing its fecal excretion through the bile in a WD rat model of severe (acute) liver damage. Here, we extend our studies on the effects of ARBM-101 to a mouse model of chronic liver damage due to spontaneous hepatic copper accumulation. Moreover, we present our evaluation of the ARBM-101 in vitro safety profile and further understanding of its mode of action have strengthened its therapeutic potential.

To test whether ARBM-101 can protect mice from developing advanced liver damage, a genetic mouse model of WD, the Atp7b^-/-mouse, was treated i.p. every other day for two weeks followed by maintenance injections every two weeks over 3 months. To test whether ARBM-101 protects animals from acute liver failure and death, LPP rats were treated with ARBM-101 at different disease stages, using several parameters including body weight loss and elevation of liver enzymes to determine disease severity. In vitro inhibitor assays were performed to understand entry/exit mechanisms of ARBM-101 in HepG2 cells in the presence or absence of copper. Ceruloplasmin activity assays were also performed using human serum samples.

Results:

Similar to WD rats, the Atp7b^-/- mice treated with ARBM-101 showed a pattern of predominant fecal copper excretion with improved parameters of liver damage. Further, we report the rescue of male WD rats, from severe disease stages by ARBM-101, showing normalization of liver enzymes and stabilization of body weight. Ceruloplasmin activity in human sera was not significantly affected by addition of excess ARBM-101 in vitro. Potential mechanisms of ARBM-101-mediated copper excretion have been unraveled with involved transporters, including MRP2, as organic anion transporters.

Conclusion:

Our data highlight the excellent therapeutic potential and safety profile of ARBM-101 for acute and chronic liver diseases in WD.