- A European phase 2a trial of a novel inhibitor of cathepsin K, a protease that mediates bone resorption and cartilage degradation, found that reduced bone and cartilage thinning in osteoarthritis (OA), but not reduced pain, was the primary outcome.
Why this matters
- This trial is among the first to study a disease-modifying drug (MIV-711), as none is on the market.
- 26-week randomized, double-blind, placebo-controlled phase 2a trial at 6 European centers.
- 244 participants with OA of Kellgren-Lawrence grade 2 or 3 and Numerical Rating Scale (NRS) for pain of 4-10 (scale 0-10).
- 3 groups were tested: placebo, 100 mg daily group, and 200 mg daily group of the inhibitor.
- Primary outcome: NRS pain reduction.
- Bone and cartilage thinning were assessed by MRI.
- Funding: Medivir.
- NRS pain:
- No significant change from baseline in all groups at 26 weeks.
- Bone area:
- The inhibitor groups showed reduced thinning, with significant difference vs placebo in least-squares means in the 100-mg group (P=.002) and the 200-mg group (P=.004).
- Medial femoral joint cartilage:
- 1 inhibitor group showed reduced thinning, with a significant difference vs placebo in least-squares mean in the 100-mg group (P=.023) but not the 200-mg group (P=.125).
- Short duration.