EAST-1 (ERAP-inhibition in Axial Spondyloarthritis Trial - 1)

Parts A, B and C: Incidence of treatment emergent (TEAE) and treatment related adverse events (TRAEs)

Any adverse event AE reported or observed after the start of dosing with any study treatment until completion of the last study related procedure (includes follow-up for safety assessments) will be recorded as a treatment-emergent AE (TEAE). If the TEAE is considered related to the study drug as per the definitions of relatedness listed in ('possibly', 'probably' or 'definitely' related) it will be considered a treatment-related AE (TRAE).

Parts A and B: Incidence and nature of dose limiting events (DLEs).

DLEs are on Grade 2 (moderate) events that are classified as related to study drug and are not resolved within 7 days. Any Grade 2 events lasting longer than 7 days, events of a higher grade, events that require study drug discontinuation or which meet the criteria for Seriousness and are related to study drug are counted as DLEs.

Analysis of clinical response per Assessment of SpondyloArthritis International Society (ASAS) core outcome set compared to placebo. Higher scores mean worse outcome: Continuous Calculated Scores

The ASAS core outcome set (COS) will be conducted in participants and includes the following questionnaires which use Continuous Calculated Scores: Ankylosing Spondylitis Disease Activity Score (ASDAS)- A specific mathematically weighted index that combines patient-reported outcomes and blood inflammatory markers. Bath Ankylosing Spondylitis Function Index (BASFI) - A mean score derived from 10 individual visual/numeric questions regarding physical function. Assessment of SpondyloArthritis (ASAS) Health Index - A composite health and functioning score calculated from a specific 17-item questionnaire.

Analysis of clinical response per Assessment of SpondyloArthritis International Society (ASAS) core outcome set compared to placebo. Higher scores mean worse outcome: Numeric Rating Scales

The ASAS core outcome set (COS) will be conducted in participants and includes the following questionnaires which use numeric rating scales (0-10): NRS Patient Global Assessment of Disease Activity (PGA-DA): A single 0-10 scale rating overall disease impact. NRS total back pain (BASDAI Q2): A single 0-10 scale rating spinal pain. NRS fatigue (BASDAI Q1): A single 0-10 scale rating tiredness levels. NRS average duration and severity of morning stiffness (BASDAI \[Q5+Q6\]/2): An average calculation derived from two separate 0-10 numeric rating scales.

Parts A, B and C: PK - trough concentrations (Cmin)

PK samples will be collected during the study to measure the to measure how the study drug moves into, through, and out of the body over time, and how its concentration in the body changes over time. Whole blood will be collected for the determination of GRWD0715 levels in plasma. The trough is the lowest concentration of a drug reached in the body, it is collected from a blood sample drawn immediately before administering the next scheduled dose.

Parts A, B and C: PK - maximum observed concentration (Cmax)

The Cmax is the highest measured drug concentration in the blood or plasma after a dose and is measured or identified directly as the highest peak data point on the experimental concentration-time graph.

Parts A, B and C: PK - time to Cmax (Tmax)

This is the exact time elapsed from drug administration until the peak concentration (Cmax) is reached and is found by looking at the time value on the x-axis that corresponds directly to the peak concentration of the drug in the blood.

Parts A, B and C: PK - area under the concentration-time curve (AUC0-t)

A measure of the total drug exposure in the body from time zero up to the timepoints specified below for each study Part.