“From a clinical perspective, there have been a vast array of clinical trials looking at different types of MSCs and different types of administration,” Dr. Hunter noted. Pooled data suggest that stem cell therapy does help to improve pain and function. However, the quality of trials has been called into question, with a positive publication bias suggested. There’s no clear evidence of any structural benefits, Dr. Hunter stated. “There’s a lot of stem cells being used for clinical purposes without the evidence to support their efficacy,” he cautioned. “We need much better regulation.”
There are several PRP agents, which deliver growth factors, cytokines, adhesive proteins, and other plasma proteins, such as clotting factors. It’s unknown how PRP therapy works in OA, whether it is just pain relieving or could affect the progression of joint damage. So far, studies have been done only in knee OA, so data in other joints need to be obtained.
“Whilst they have great potential, the literature on the use of PRP is conflicting,” Dr. Hunter said. “There are a lot of positive trials out there, but their quality in general is quite low.”
Better data are perhaps available for the recombinant human fibroblast growth factor–18 sprifermin, with recent 3-year data from an ongoing 5-year randomized, placebo-controlled, phase 2 study showing increased total cartilage thickness in the tibiofemoral joint relative to placebo. “There does appear to be a structure benefit,” Dr. Hunter said of sprifermin’s effects in the study versus intra-articular saline.