∙ Healthy Volunteers

• Healthy male and female subjects aged 18-55 years inclusive, at the Screening visit

• Participant must provide written informed consent to participate in the study

• Participant must be able and willing to comply with the requirements of the protocol (including dietary restrictions and exclusion of grapefruit juice)

• Male participants (and their female partners) / female participants must be willing to adhere to contraception requirements as detailed in the protocol

• Non-smokers or ex-smokers who have not smoked within the previous 6 months, as determined at the Screening visit

• Participant with a Body Mass Index (BMI) of 19-30. Body Mass Index = Body weight (kg) / \[Height (m)\]2

∙ AxSpA Participants

• Male or female, 18-65 years of age

• Participants diagnosed with Axial Spondyloarthritis, also fulfilling ASAS classification criteria including:

‣ HLA-B27 +ve (local testing)

⁃ Objective evidence of inflammation at screening, specifically active sacroiliac joint inflammation on MRI fulfilling the ASAS MRI criteria (MRI+), assessed by the Principal Investigator or appropriately trained delegate, and/or elevated C-reactive protein (CRP+) ≥5.0mg/L.

• Symptom duration of ≥3 months

• Age at onset of active disease of \<40 years

• A score of ≥ 2.1 on the Ankylosing Spondylitis Disease Activity Score (ASDAS) on current treatment.

• At least one of the following:

‣ Current treatment with a NSAID, at a sufficient dose and following an appropriate dosing duration per local clinical guidelines, with inadequate clinical response OR

⁃ Intolerance to ≥1 NSAID or contraindication(s) to NSAIDs

• Participants may have received 1 prior/(Australia only) 2 prior b/ts DMARD and discontinued due to intolerance or inadequate efficacy.

• Participants who have received 1/(Australia only) 2 prior treatments are required to undergo a washout at minimum:

‣ Biologic DMARDs 4 weeks or 5 half-lives prior to Day 1, whichever is longer.

⁃ JAK inhibitor DMARDs 2 weeks prior to Day 1