The purpose of this study is to evaluate the clinical response in subjects with symptomatic OA of the knee following a single 50 mg anakinra, 150 mg anakinra or placebo intra-articular (IA) injection.

Inclusion Criteria: - Diagnosed with knee OA as determined by American College of Rheumatology (ACR) criteria - Pain defined by a level of greater than 30 mm on a 100 mm Visual Analogue Scale (VAS) - No evidence of active effusion or inflammatory flare, confirmed by investigator - Must exhibit radiographic evidence of tibio-femoral compartment knee OA within 12 months of screening - Stable doses of any non-prescribed supplements (e.g. glucosamine or chondroitin sulphate, shark cartilage, diacerhein, soya extract) for at least 2 months prior to screening - Unchanged use of physical therapy, biomechanical devices or orthotic support within at least 2 months of screening - Subjects on nonsteroidal anti-inflammatory drug (NSAID) therapy must discontinue NSAIDs 3 days prior to baseline (Day 1) - Before any study-specific procedure is performed, the appropriate written informed consent for participation in the study must be obtained Exclusion Criteria: - Malignancy within the previous 5 years, except for basal cell or in situ cancer - Significant hematologic disease - Active infection or history of recurrent or chronic infections - Known diagnosis of HIV, hepatitis B, or hepatitis C infection - Uncontrolled diabetes or cardiovascular disease and hypertension - Inflammatory arthropathy including secondary OA - Isolated OA of the patellofemoral joint (bi or tri-compartmental involvement are not exclusions) - End-stage ("bone-on-bone") OA (Kellgren Lawrence score of 4) - OA of the hip ipsilateral to the index knee - Total white cell count less than 2.0 x 109/L and/or platelet count less than 100 x 109/L observed within 1 month preceding screening - Prior IA injection of anakinra or experimental interleukin-1 (IL-1) inhibitor therapy - Concurrent treatment with subcutaneous (SC) anakinra - Concurrent or recent (less than or equal to 1 month) use of experimental therapy - Prior IA corticosteroid injection within 1 month of study - Prior viscosupplement therapy within 3 months of study - Contraindication(s) to IA injections - Subjects who are pregnant or breast-feeding, or plan to become pregnant during the study - Subject is not using adequate contraception - Known allergy to E coli-derived products - Unable to understand informed consent - Concerns regarding subject's compliance with the protocol procedures - Subject will not be available for follow-up assessment - Active substance abuse