ObjectiveTo explore the safety, and efficacy of a proprietary hydrolyzed oil extract from seeds of Biota orientalis (hBO/Epiitalis®, Interpath Pty Ltd) in patients with knee pain due to osteoarthritis (OA).MethodsPatients aged 40–65 with X-ray diagnosed knee OA and knee pain ≥ 60 on a 100-point VAS (visual analog scale) were enrolled and randomized into four groups to receive daily hBO for 56 days as high (hBO-HD, 640 mg), mid (hBO-MD, 320 mg) or low (hBO-LD, 160 mg) doses, or a matched placebo oil. The primary outcome was change in VAS knee pain from baseline to 56 days in the mITT (modified intention to treat) population. Exploratory outcomes were the mWOMAC (modified Western Ontario and McMaster Universities Arthritis Index), and the SF-36 QoL (quality of life) questionnaire. The OMERACT-OARSI (Outcome Measures in Arthritis Clinical Trials–Osteoarthritis Research Society International) responder index was also calculated.Results223 patients were included in the mITT population. Reductions in VAS scores between baseline and day 56 [Least square mean (LS mean) and 95% confidence interval (CI) of LS mean] were 36.4 (31.7–41.0), 37.9 (33.2–42.7), 35.7 (31.2–40.1) and 9.8 (14.5–15.2) for the hBO-HD, hBO-MD, hBO-LD, and placebo groups respectively. The VAS changes in all hBO groups were significantly different (p < 0.0001) vs. changes in the placebo group. hBO treatment led to similar quantitative beneficial changes in mWOMAC, SF-36 and OMERACT-OARSI responder index. There were no SAEs and no adverse events ascribed to the intervention.ConclusionIn a 56-day trial, hBO was safe, and was efficacious at reducing symptoms in patients with knee OA. Registration: NCT04117490; Oct 7, 2019.