Clinical responders to belumosudil had reductions in OM IL-17 cells, immune cells, and local type I collagen that were not observed in nonresponders. (A) Pie chart showing the percentage of total patients (n = 20) with overall clinical response of MX, PD, UN, or PR. (B) Overall clinical response classification of changes in OM collagen type I and IL-17⁺ cells between responders and nonresponders with belumosudil (n = 16). Responders included PR, and nonresponders included MX, PD, and UN. (C) Pie chart showing percentage of total patients (n = 20) with clinical mouth response of UN, PD, PR, and CR. (D) Clinical mouth response classification of differences in percentage area of collagen type I, IL-17⁺, CD3⁺ T, CD4⁺, and CD3⁺CD4⁺ T cells before and after treatment in the cohort (n = 16) of responders and non-responders in the OM. Responders included PR and CR, and nonresponders included UN and PD. P value <.05 is considered significant. Wilcoxon signed-rank test was performed. MX, mixed response.