The principal aim of this study is to obtain safety and tolerability data when PXT002331 is administered orally as single and multiple doses to healthy subjects.

Inclusion Criteria:

1. Subjects will be; 1.1. males or females of non childbearing potential 1.2. For females, non childbearing potential is defined as follows:

   • permanently sterile following hysterectomy, bilateral salpingectomy, bilateral oophorectomy, or confirmed tubal occlusion (not tubal ligation)
   • postmenopausal, defined as at least 1 year post cessation of menses (without an alternative medical cause) 1.3. of any ethnic origin 1.4. between 18 and 60 years of age, inclusive

2. Subjects will have a 2.1. body mass index (BMI) between 18.0 kg/m2 and 32.0 kg/m2, inclusive 2.2. body weight between 50 kg and 100 kg, inclusive

3. Subjects will be in good health, as determined by; 3.1. medical history 3.2. physical examination 3.3. vital signs assessment 3.4. 12 lead ECG and 24 hour Holter Monitoring 3.5. clinical laboratory evaluations (congenital non haemolytic hyperbilirubinaemia is not acceptable)

4. Subjects will have given their written informed consent to participate in the study and to abide by the study restrictions