Comparative efficacy and safety of Verbascox® − a proprietary herbal extract capable of inhibiting human cyclooxygenase-2 − and celecoxib for knee osteoarthritis

The aim of this randomized, single-blind, active-controlled pilot study was to investigate the clinical efficacy of oral supplementation with Verbascox®, a proprietary herbal extract capable of inhibiting human cyclooxygenase-2 (COX-2), in patients with mild-to-moderate osteoarthritis (OA) of the knee. Patients in the control group (n = 50) did not undergo any treatment (watchful waiting). Patients in the Verbascox® group (n = 50) received oral supplementation (800 mg/day) with the herbal extract for 2 weeks. The final study group consisted of patients (n = 50) who received celecoxib, a known pharmacological inhibitor of COX-2, 200 mg/day for 2 weeks. Examining physicians and laboratory personnel were blinded to group assignment, whereas patients were unblinded. All participants were evaluated using standard measures of pain relief and improvement in functional capacity at baseline, after 1 week, and at the end of the 2-week treatment course. Moreover, serum levels of substance P (SP), a member of the tachykinin family of neuropeptides involved in pain perception, were measured at the three time points. Both Verbascox® and celecoxib reduced pain, improved functional capacity, and lowered serum SP levels at 2 weeks compared with baseline, without significant inter-arm differences. Both Verbascox® and celecoxib showed a limited number of treatment-emergent adverse events. In summary, oral supplementation with Verbascox® (800 mg/day) in patients with mild-to-moderate OA of the knee is as effective and safe as a standard therapeutic dose of celecoxib in terms of pain relief and improvement in functional capacity after a 2-week treatment course.