A Dose-Finding Study to Evaluate the Efficacy and Safety of GSK3858279 in Adults With Knee Osteoarthritis (OA) Pain

Inclusion Criteria:

• Participant must be 40 to 80 years of age inclusive

• OA of the index knee as defined by symptomatic for ≥ 6 months with a clinicaldiagnosis of OA as per American College of Rheumatology (ACR) clinical diagnosiscriteria.

• Kellgren and Lawrence (KL) score ≥ 2 on X-ray in the index knee

• An average of the average daily pain score of ≥4 and less than or equal to (≤) 9 bythe 11-point NRS (0-10)

• Body mass index (BMI) of < 40 kilogram per meter square (kg/m^2) (inclusive).

• Capable of giving signed informed consent.

Exclusion Criteria:

• History or presence of cardiovascular, renal, gastrointestinal, lymphatic disorderswhich in the opinion of the investigator would interfere with the study proceduresand/or assessments.

• History or current evidence of any inflammatory arthritis such as rheumatoidarthritis, infective arthritis, Paget's disease, osteonecrosis, osteoporoticfracture, or any other joint disease that in the Investigator's opinion wouldinterfere with the assessment of pain and other symptoms of osteoarthritis.

• History of significant trauma or surgery to a knee or hip within the last 6 months.

• Current immunodeficiency diseases including but not limited to acquiredimmunodeficiency disorder or immunoglobulin deficiency.

• Current or previous active Mycobacterium tuberculosis

• History or evidence of clinically significant multiple or severe drug allergies

• History of malignancy within the last 5 years, except for basal cell or squamousepithelial carcinomas of the skin that have been resected with no evidence ofmetastatic disease for 3 years.

• Alanine transaminase (ALT) >1.5 times upper limit of normal (ULN).

• Bilirubin >1.5 times ULN (isolated bilirubin >1.5 times ULN is acceptable ifbilirubin is fractionated and direct bilirubin < 35 percent (%)

• Current or chronic history of liver disease, or known hepatic or biliaryabnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones)

• Evidence of renal insufficiency, indicated by estimated creatinine clearance < 60milliliter/ minute (mL/min)/1.73 square meter (m^2) at screening.

• Sensitivity to any of the study interventions, or components thereof, or drug orother allergy that, in the opinion of the investigator or medical monitor,contraindicates participation in the study.