WOMAC

WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index)

WOMAC is a validated, patient-reported questionnaire used to assess the impact of knee or hip osteoarthritis on three domains: pain (5 items), stiffness (2 items), and physical function (17 items). It is one of the most widely used outcome measures in osteoarthritis clinical research and is recognized by regulators as a valid endpoint for evaluating therapies that target osteoarthritis-related disability.

Scores can be reported on different scales depending on the version used; the percent-change-from-baseline format is common for reporting treatment effects. A WOMAC pain reduction of approximately 50% or more is typically considered clinically meaningful.

In retatrutide’s Phase 3 program, WOMAC pain was a co-primary endpoint in TRIUMPH-4, which enrolled adults with obesity and knee osteoarthritis. The trial reported WOMAC pain reductions of 75.8% at the 9 mg dose and 74.3% at the 12 mg dose over 68 weeks, exceeding the effect sizes typically observed with weight loss alone or with conventional osteoarthritis therapies.