A Four-Week Multicenter Study Evaluating the Safety and Efficacy of AF-219 in Subjects With Osteoarthritis of the Knee

Subjects who satisfy entry criteria at Screening will enter the Washout Phase, discontinuing
their current nonsteroidal anti-inflammatory drug (NSAID) therapy.

Up to 220 subjects who fulfill flare (and other entry) criteria will be randomized to AF-219
or placebo.

Subjects will complete Treatment Visits 1, 2, 3, and 4 weeks after starting study drug. At
each Treatment Visit, subjects will undergo efficacy assessments and safety procedures.
During the Washout and Treatment Phases subjects will complete the 'average pain' Numeric
Pain Rating Scale (NPRS) and count of rescue medication used for the preceding 24 hours.

Subjects will return 2 weeks after their last Treatment Visit (for a Follow-Up Visit).

Inclusion Criteria:

- Men or women

- Women of child bearing potential must not be pregnant during the study and must use
two forms of birth control

- Men and their female partners must use two forms of birth control

- Clinical and radiographic evidence of chronic knee osteoarthritis

- Minimum pain at Screening and during Washout

- Ambulatory

- Have provided written informed consent