Use of amnion-derived cellular cytokine solution for the treatment of gingivitis: A 2-week safety, dose-ranging, proof-of-principle randomized trial

Abstract

Background: A 6-week Phase I clinical trial was performed to primarily evaluate the safety and secondarily determine the preliminary efficacy of a novel biological solution, ST266, comprised of a mixture of cytokines, growth factors, nucleic acids, and lipids secreted by cultured amnion-derived multipotent progenitor cells on gingival inflammation.

Methods: Fifty-four adults with gingivitis/periodontitis were randomly assigned to 1X ST266 or diluted 0.3X ST266 or saline topically applied on facial/lingual gingiva (20 µL/tooth). Safety was assessed through oral soft/hard tissue exam, adverse events, and routine laboratory tests. Efficacy was assessed by modified gingival index (MGI), bleeding on probing, plaque index, probing depth (PD), and clinical attachment level (CAL). Assessments were performed on day 0, 8, 12, and 42. ST266 and saline applied daily starting at day 0 through day 12 except weekend days. Plasma was analyzed for safety and proinflammatory cytokines, interleukin (IL)-1β, IL-6, tumor necrosis factor-alpha, and interferon gamma. Gingival crevicular fluid (GCF) was analyzed for the same cytokines. Subgingival plaque was primarily analyzed by checkerboard DNA-DNA hybridization. Comparisons with saline were modeled through a generalized estimating equations method adjusting for baseline.

Results: No safety concern was found related to ST266. Statistically significant reduction in MGI was noted at day 42 by 1X ST266 compared with saline (P = 0.044). PD and CAL were reduced by both doses of ST266 at day 42 (P <0.01) and by 1X ST266 at day 12 (P <0.05). GCF IL-1β and IL-6 levels were reduced by both doses of ST266 at day 12 (P <0.05, P <0.01, respectively). IL-6 was also significantly reduced in plasma of both ST266 groups (P <0.05). Significant reductions in red complex bacteria were detected in both ST266 doses.

Conclusions: In this "first in human oral cavity" study, topical ST266 was safe and effective in reducing gingival inflammation in 6 weeks. Longitudinal studies with large sample sizes are warranted to assess the therapeutic value of this novel host modulatory compound in the treatment of periodontal diseases.

Keywords: cytokines; gingival crevicular fluid; gingivitis; host modulation; inflammation; periodontal disease.

FIGURE 1

Change in primary outcome, gingival index, at day 42. Differences were detected in gingival index (MGI) between placebo and both doses of ST266 at all time points; day 8, 12, and 42 (analysis adjusted for baseline differences). Statistically significant differences were noted for primary efficacy end point MGI at day 42 with 1X ST266 compared with placebo. *Significant difference at P <0.05

FIGURE 2

Change in bacterial counts of periodontal species. Fourteen periodontal bacteria were semi‐quantitively analyzed using DNA‐DNA hybridization checkerboard assay at baseline and at day 10 after treatments. Mean differences of change from baseline in ST266‐treated groups were compared with the change from baseline in place group. Both red and orange complex species known to be strongly associated with periodontal disease showed significant reductions on day 10 after treatment with ST266. Mean differences, 95% confidence intervals, and P values comparing 0.3X ST266 and 1X ST266 to placebo using GEE analysis. *Significant difference at P <0.05

FIGURE 3

Change in levels of proinflammatory cytokines in gingival crevicular fluid. Levels of proinflammatory cytokines including IL‐1β, IL‐6, and TNF‐α in GCF were determined using a multiplexing platform. Mean differences of change from baseline in ST266‐treated groups were compared with the change from baseline in place group. Significant reductions were found in the levels of IL‐1β and IL‐6 in the GCF of subjects assigned to both 0.3X ST266 and 1X ST266 compared with placebo at day 12 after the tenth treatment (IL‐1β, P = 0.02, P = 0.015; and IL‐6, P = 0.005, P = 0.002, respectively). Mean differences, 95% confidence intervals, and P values comparing 0.3X ST266 and 1X ST266 to placebo using GEE analysis. *Significant difference at P <0.05