This is a single-centre, open-label, non-randomised, period fixed sequence study designed to investigate the PK and safety of Firibastat (QGC001) modified release (MR) prototype tablet formulations and compare this to a reference Firibastat (QGC001) immediate release (IR) capsule formulation in healthy male subjects.

It is planned to enrol 12 subjects to receive single oral doses of investigational medicinal product (IMP).

Subjects will be screened for eligibility to participate in the study up to 28 days before dosing and for each treatment period they will be admitted to the clinical unit on the evening prior to IMP administration (Day -1). On the morning of Day 1, subjects will receive IMP in the fasted state (or following a FDA standard high-fat breakfast, if applicable) and will remain on site until 48 h post-dose. Between the periods, an interim analysis and review of safety and PK data from dosed regimens will be performed in order to determine which Firibastat (QGC001) MR prototype tablet formulation and dose to administer in subsequent periods. A follow-up phone call will take place 7 to 10 days post-final dose to ensure the ongoing wellbeing of the subjects.

Inclusion Criteria:

• Body mass index of 18.0 to 32.0 kg/m2
• Must adhere to the contraception requirements

Exclusion Criteria:

• Subjects who have received any IMP in a clinical research study within the previous 3 months
• Subjects with pregnant partners
• History of any drug or alcohol abuse in the past 2 years
• Clinically significant abnormal biochemistry, haematology or urinalysis
• Subjects with BP <90/50 mmHg at screening