A multi-centre, open label, long-term follow-up study to evaluate the benefits of a new viscoelastic hydrogel (HYMOVIS^®) in the treatment of knee osteoarthritis**

F. Benazzo, L. Perticarini, A. Padolino, A. Castelli, P. Gifuni, M. Lovato, C. Manzini, N. Giordan

Viscosupplementation with intra-articular injection of hyaluronic acid (HA) is widely used for the treatment of pain in osteoarthritis (OA) of the knee in patients who have failed to respond adequately to conservative non-pharmacologic therapy or simple analgesics.

HYMOVIS^® is a newly marketed HA manufactured by Fidia Farmaceutici S.p.A., Abano Italy, and distributed by its wholly owned subsidiary, Fidia Pharma USA Inc., Parsippany, NJ. HYMOVIS^® consists of an 8mg/mL hydrogel formulation of HYADD®4, a unique molecule, which is not chemically crosslinked and has a low degree of modification that increases viscosity, elasticity and joint residence time* (HYMOVIS package insert).

This is a prospective, multicentre, open label, 12 months follow-up, clinical study to evaluate the long-term benefits of 2 cycles of treatment with 2x3 ml intra-articular injections of 8 mg/ml of HYMOVIS^® in the treatment of knee OA (n=49 outpatients). Each injection cycle was given at weekly intervals for two weeks, repeated at 6 months.

• Primary objective: pain measured by WOMAC pain (A) subscore over 12 months.
• Secondary objectives: pain stiffness and physical function; radiological progression of knee OA; patient’s response to therapy (OMERACT-OARSI); Quality of Life.

Results

• WOMAC pain (A) subscore: a statistically significant improvement from baseline was evidenced at each time point.
• WOMAC A1 score (pain on walking): significant improvement vs baseline (p<0.001) at 12-month follow-up.
• WOMAC pain stiffness, physical function and total score: significant improvement by 3 months and 6 months after one intra-articular injection cycle, and up to 12 months after repeat treatment with HYMOVIS (p<0.001).
• OMERACT-OARSI criteria: 86% responder rate reported in this study after 6 months, and 88% responder rate reported in the study at 12 months after one repeat cycle of treatment.
• JSW reduction of 0.2mm: Study criteria defined disease progression as ≥ 0.5mm; the mean baseline in the target knee was 4.6mm and progressed to a mean value of 4.2mm at the end of the study.
• EQ5D (Quality of Life index): significant increase vs baseline at each time point (p<0.001).

Clinical performance and safety of HYMOVIS^® in the treatment of pain due to knee OA, demonstrated in previous studies has been confirmed by the results of this study.