Frozen Shoulder syndrome is a disorder of diminished shoulder motion, characterized by restriction in both active and passive range of motion of the shoulder joint. Frozen Shoulder usually affects patients aged 40-70 years. It is estimated that 3% of people develop Frozen Shoulder over their lifetime and that women tend to be affected more frequently than men. The condition may affect both shoulders, either simultaneously or in sequence. Recurrence of Frozen Shoulder is common within five years of disease onset. The most common treatments for Frozen Shoulder are extensive physical therapy, corticosteroids, and/or arthroscopy. Drugs are used to control pain, but none have been demonstrated to have an impact on the underlying disease process. Likewise, medications have not been shown to affect the duration of disease or the severity or duration of joint contracture. Intralesional injections of Xiaflex have been evaluated in phase II studies.

Clinical Trial Results

These early phase II trials showed efficacy and tolerability. The study was a randomized, placebo-controlled, and double-blind dose-response study. There were 60 patients enrolled in the protocol: 47 women and 13 men. All patients received a randomized, placebo-controlled first injection of 0.5 mL of placebo or 0.145 mg, 0.29 mg, or 0.58 mg collagenase diluted in physiologic saline. Outcome measures were conducted using a form by the American Society of Shoulder and Elbow Surgeons. Function score, pain score, strength, and stability were measured. Results demonstrated that there was a clinically meaningful difference in return to normal shoulder motion and function with drug treatment compared with placebo. Patients who received additional open-label 0.58 mg collagenase injections had improvements in shoulder motion, function, and pain. These improvements occurred one day post-injection and at one month, improvements were comparable to normal values. Ongoing trials are planned to assess dosing and dosing regimen.