Experimental Growth Factor May Aid Knee Osteoarthritis

However, clinical significance uncertain as patients did not report symptom improvement

THURSDAY, Oct. 17, 2019 (HealthDay News) -- An experimental growth factor therapy, sprifermin, may prevent a worsening of osteoarthritis by increasing the thickness of cartilage in the knee, according to a study published in the Oct. 8 issue of the Journal of the American Medical Association.

Marc C. Hochberg, M.D., from the University of Maryland in Baltimore, and colleagues randomly assigned participants in the FGF-18 Osteoarthritis Randomized Trial with Administration of Repeated Doses (median age, 65 years; 69 percent female) with symptomatic, radiographic knee osteoarthritis to five groups: intra-articular injections of 100 µg of sprifermin administered every six months (110 patients) or every 12 months (110 patients), 30 µg of sprifermin every six months (111 patients) or every 12 months (110 patients), or placebo every six months (108 patients).

The researchers found that compared with placebo, the changes from baseline to two years in total femorotibial joint cartilage thickness were 0.05 mm for 100 µg of sprifermin administered every six months, 0.04 mm for 100 µg of sprifermin every 12 months, 0.02 mm for 30 µg of sprifermin every six months, and 0.01 mm for 30 µg of sprifermin every 12 months. There were no statistically significant differences in mean absolute change from baseline in total Western Ontario and McMaster Universities Osteoarthritis Index scores for any dose or time frame compared with placebo. The most common treatment-emergent adverse event was arthralgia.

"While the increase in cartilage thickness is a positive sign, we do not know at this point whether it has any clinical significance," Hochberg said in a statement. "It is not known whether those who experience increased cartilage thickness over time will be able to avoid or delay knee replacement surgery."

Several authors disclosed financial ties to pharmaceutical companies, including Merck, which funded the study.

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