CD25 expression could be a prognostic marker of bexarotene monotherapy for cutaneous T-cell lymphomas.

Bexarotene is often administered to phototherapy-resistant early cutaneous T-cell lymphoma (CTCL) patients as one of the first-line therapies in real-world practice. Since bexarotene reduces the expression of CCR4 in CTCL cells and CCL22 to decrease serum CCL22 levels, bexarotene inhibits the migration of CTCL cells, as well as other CCR4+ cells, such as cytotoxic T cells and regulatory T cells, in the lesional skin of CTCL. In this report, the efficacy of bexarotene in 28 cases of CTCL, as well as its correlations with immunohistochemical profiles of tumour-infiltrating leucocytes (TILs), was retrospectively investigated. The overall response rate at 1 and 4 months for the total cohort was 70.8% (95% CI, 50.6%-86.3%) and 47.8% (95% CI, 29.2%-67.0%), respectively. The disease control rate for the total cohort at 4 months was 65.2% (95% CI, 44.8%-81.3%). The mean event-free survival for all patients was 4.1 months (0.3-68.5 months). In addition, the immunoreactive cells were calculated using digital microscopy, suggesting that the ratio of CD25+ cells among TILs was significantly increased in patients who responded to bexarotene (p = 0.0209), whereas there were no significant differences in the ratios of CD8+ cells, granulysin+ cells, and Foxp3+ cells among TILs between responder and non-responder patients. Collectively, the ratio of CD25 expression among TILs might be a predictive biomarker for the efficacy of bexarotene.

Quantitative Analysis of Immune-Reactive Cells among Leukocytes Is Useful for the Diagnosis of Drug Eruptions Caused by Bexarotene.

Bexarotene is a third-generation retinoid X receptor-selective retinoid that has been approved for use in the treatment of cutaneous T-cell lymphomas (CTCLs). Since the objective response rate of bexarotene is relatively high, with no racial differences, bexarotene can be administered to patients with phototherapy-resistant early CTCL as one of the first-line therapies in real-world clinical practice. Although various adverse events caused by bexarotene have been reported, there have been no reports of drug eruptions caused by bexarotene. One of the possible reasons is that it is difficult to distinguish a drug eruption from recurrence of CTCL, histologically. In this report, drug eruptions in 2 patients with CTCL treated with bexarotene diagnosed by quantitative analysis of immunohistochemical staining by digital microscopy are described.