Effect of E-PR-01 on Activity-Induced Acute Knee Joint Discomfort in Healthy Individuals: A Randomized, Placebo-Controlled, Double-Blind, Cross-Over Study

PURPOSE: A randomized, double-blind, placebo-controlled cross-over study was conducted to investigate the efficacy and safety of E-PR-01, a proprietary formula containing Vitex negundo and Zingiber officinale, on knee joint discomfort due to pain. PATIENTS AND METHODS: Forty adults aged 20–60 years with self-reported pain score of ≤30 mm at rest and ≥60 mm post-exertion on a 100-mm visual analog scale (VAS) were randomized in a 1:1 ratio to receive either the E-PR-01 (200 mg twice daily) or placebo for 5 days. The primary outcome was time to achieve meaningful pain relief (MPR) (≥40% reduction in post-exertion pain VAS score from baseline) post-single dose of intervention on day 1 compared to placebo. The secondary outcomes were post-exertion pain intensity difference (PID) at 2-, 3- and 4-hours and time-weighted sum of pain intensity difference (SPID) over 4 hours post single dose on day 1; post-exertion VAS score at 4 hours’ post-intervention on day 5; percentage of responders on day 1; and physical efficiency as assessed by the total duration of exercise sessions completed after single dose of IP compared to placebo. RESULTS: The average time to achieve MPR was 3.38 hours, 32.50% of participants achieved it in the E-PR-01 group post single-dose administration on day 1 as opposed to the placebo where no participant achieved MPR. There were significant intergroup differences in PID (−23.58 vs 2.45 mm) and SPID (−67.48 vs −0.08 mm) at 4 hours of E-PR-01 and placebo administration on day 1. 95% of participants in the IP group experienced some degree of pain relief within 2 hours compared to 37.5% in the placebo group. CONCLUSION: A single dose of E-PR-01 provided a statistically significant as well as clinically meaningful reduction in exercise-induced knee joint discomfort within 4 hours of administration.