Muscle Injury

Pluristem conducted a Phase II, randomized, double blind, placebo controlled trial in patients undergoing a total hip replacement (THR) due to osteoarthritis. The aim of the study was to evaluate the safety and efficacy of 2 doses of PLX-PAD for the regeneration of the gluteus medius muscle injured during the THR. Patients were assigned to receive either 150 or 300 million PLX-PAD cells, or placebo. PLX-PAD or placebo were administered directly to the injured muscle during the surgery.

Efficacy data were collected at clinic visits for up to 6 months, while safety data were collected during clinic visits for up to 1 year.

The primary efficacy endpoint was the change in the strength of the gluteus medius muscle 6 months after surgery, and the key secondary endpoint was the change in the muscle volume of the gluteus medius 6 months after surgery, as measured by magnetic resonance imaging (MRI).

The study met both the primary efficacy and key secondary endpoints. Both patient groups treated with PLX-PAD showed efficacy, as measured by a greater increase in the gluteus medius muscle strength than the patients receiving placebo, with the group receiving the 150 million cell dose displaying a statistically significant 500% improvement over the placebo group (p=0.0067). Patients treated with the 300 million cell dose showed a 300% improvement over the placebo (p=0.18).

Graph 1: Mean change in strength of the Gluteus Medius at Week 26 post surgery

Muscle Injury 1

MRI of the gluteus medius muscle indicated an increase in volume in those patients treated with PLX-PAD versus the placebo group. Those who received the 150 million cell dose showed a statistically significant improvement in muscle volume of approximately 300% over the placebo group (p=0.004). Patients treated with the 300 million cell dose showed an approximately 150% improvement approximately 150% over placebo (p=0.19).

Graph 2: Mean change in volume of the Gluteus Medius at Week 26 post surgery

Muscle Injury 2

Data also showed that, six months after surgery, the magnitude of improvement in the muscle force of the contralateral (non-operated) gluteus medius muscle was approximately 40 times larger in patients treated with 150 million PLX-PAD cells than in those who received placebo, and the difference was statistically significant (p=0.0114). Patients treated with 300 million PLX-PAD cells also showed a larger increase in muscle force than patients injected with placebo (p=0.227). These data on the force of the muscle in the contralateral leg suggest that PLX-PAD cells can exert a systemic as well as a local effect.