A Single Ascending and Repeated Dose Study of Oral ZF874 in Healthy Volunteers and PiXZ Subjects

This study is composed of two parts. Part A: will test single doses of ZF874 in a double-blind, randomised, placebo-controlled and dose-escalating design (except Group 7, which will be open-label and without placebo). Up to 7 groups of 6-8 healthy volunteers will receive an oral dose of ZF874 or matching placebo (6 active: 2 placebo in Groups 1-6; 6 active in Group 7). The dosing of the first 2 subjects (1 active and 1 placebo) will take place before dosing of the remainder of the group in Groups 1-6, with morning doses given in the fasted state. The dose will be escalated only if the safety and tolerability of the previous highest dose are acceptable, and the plasma concentrations of ZF874 are predicted to remain below the toxicokinetic exposure limit, as determined by the Safety Review Group. Group 7 will consist of 6 subjects, all of whom will receive ZF874 after consuming a standard high-fat breakfast. Dosing of the first 2 subjects before the rest of the group is not required in Group 7, as 6 subjects have already safely received ZF874 at this dose in Group 3 and 12 subjects have already safely received higher doses in Groups 4 and 5. The dose selected for Part A, Group 7 was chosen as the dose has previously been given to subjects fasted in Group 3, and it was safe and well tolerated, allowing for comparison for the food effect, and higher doses have been tested in Part A with no safety concerns. Part B: Multiple Ascending Doses in subjects carrying at least one Z mutated alpha-1-antitrypsin (Z-A1AT) allele (PiXZ subjects): Up to 4 groups of up to 5 PiXZ subjects will be enrolled in Part B (Groups 1-4). In Group 1, up to 4 subjects will receive twice daily doses of either ZF874 or placebo on 28 consecutive days. The dose level (dose and dose regimen) selected for Part B Group 1 will be based on review of the available results from Part A. In Groups 2-4, up to 5 PiXZ subjects will receive ZF874 twice daily by mouth for 28 days; no subjects will receive placeb