Mechanistic Insights and Real-World Evidence of Autologous Protein Solution (APS) in Clinical Use

Autologous therapies are currently being studied to determine if they can modulate the course of knee osteoarthritis symptoms and/or disease progression. One potential therapeutic target is the polarization of pro-inflammatory M1 macrophages to pro-healing M2 macrophages. The autologous therapy, Autologous Protein Solution (APS), was incubated with donor-matched human peripheral-derived macrophages for 10 days. M1 pro-inflammatory macrophages were determined by the percentage of CD80+ and M2 pro-healing macrophages were determined by CD68+ and CD163+ by epifluorescent microscopy. To determine clinical effectiveness, an APS-specific minimal clinically important improvement (MCII) using an anchor-based method was calculated in a randomized controlled trial of APS (n = 46) and then applied to a real-world registry study (n = 78) to determine the percentage of pain responders. Compared to control media, APS statistically increased the percentage of M2 macrophages and decreased the percentage of M1 macrophages, while platelet-poor plasma had no effect on polarization. In the randomized controlled trial (RCT), the MCII at the 12-month follow-up visit was calculated as 2.0 points on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale and 7.5 points on the WOMAC function scale. Applying this MCII to the real-world registry data, 62.5% of patients met the MCII with an average of 4.7 ± 2.5 points of improvement in pain. Autologous therapies can influence macrophage polarization and have demonstrated clinical effectiveness in a real-world patient setting.