Mogamulizumab efficacy on the skin compartment of cutaneous T-cell lymphomas based on longitudinal analysis

Cutaneous T-cell lymphoma is staged by the degree of skin, lymph node, viscera and blood involvement. Skin response is a determinant of treatment decisions. Mogamulizumab, an anti-CC chemokine receptor 4 antibody, is approved for mycosis fungoides and Sézary syndrome after ≥1 systemic therapy. Longitudinal changes in modified Severity-Weighted Assessment Tool (mSWAT) score, and cluster of differentiation (CD)4⁺CD7^-/CD26^- cell subsets during mogamulizumab treatment were investigated as an exploratory post-hoc analysis. While chronological differences in mSWAT scores were not interpreted by a linear mixed model (LMM) due to a statistically significant interaction term, significant differences based on responses in CD7^- (-690.5/μL; 95% confidence interval [CI], -1195 to -186.2; p = 0.0076) and CD26^- (-1029/μL; 95% CI, -1705 to -353.7; p = 0.0030) cell counts were identified. Actual values of mSWAT scores decreased for responders at Week (W) 12 and 24 from baseline (BL) (mean ± standard error: BL: 97.57 ± 6.52; W12: 52.34 ± 6.16; W24: 34.89 ± 4.93) following a rapid decrease of CD7^- cells in blood at W4 (BL: 2809 ± 650.3/μL; W4: 204.4 ± 50.76/μL; W12: 101.9 ± 28.81/μL; W24: 152.8 ± 54.98/μL). Monitoring both blood and skin improvements is important for effective mogamulizumab treatment in patients with advanced stage disease.