At that time only the 12-month primary endpoint data were available, which showed that TissueGene-C improved IKDC scores from baseline by a significantly greater amount than a saline placebo, with changes in scores of 15.1 and 5 points, respectively, versus baseline values. Improvements in IKDC scores were seen as early as 3 months but only became significantly better than placebo at 6 months.
Similarly, visual analog scale pain scores had improved from baseline as early as 3 months but were only significantly different from placebo at 6 months (–23.4 change from baseline for TissueGene-C vs. –14.6 for placebo) and out to 12 months (–24.5 vs. –10.3). WOMAC scores with TissueGene-C were only significantly different from placebo at 12 months (–13.5 vs. –6.2 from baseline, respectively).
The 12-month OMERACT-OARSI responder rate was 84% for TissueGene-C and 45% for placebo. The most common adverse events seen with TissueGene-C were related to the injection site, with peripheral edema (9%), arthralgia (8%), joint swelling (6%), and injection-site pain (5%) reported.
A total of 163 patients were recruited into the study, all had Kellgren-Lawrence grade 3 knee OA, which was also graded as 3 or 4 on the International Cartilage Regeneration & Joint Preservation Society scale. Major lesions had be 6 cm2 or smaller. Active treatment was given to 78 patients, and 81 received placebo. The primary assessment period was at 12 months, but patients continued to be followed out to 5 years.