A Phase 1, Multicenter, Open-label, Prospective, First-in-human Dose-escalation Clinical Trial of Domain Therapeutics' Anti-CCR8 Monoclonal Antibody (DT-7012) in Patients With Relapsed or Refractory Cutaneous T-cell Lymphomas (CTCL)

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of lymphomas characterized by a primary involvement of the skin. Among them, mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes. SS is defined as erythroderma (erythema of the entire skin surface), and circulating tumor blood cells. The circulating tumor T cells express CD4 and may lose expression of CD7 and CD26, while exhibiting in most cases aberrant expression of CD158k (KIR3DL2), which is a surface marker of Sézary cells. CCR8 is a surface marker of tumor-infiltrating regulatory T cells. It has recently be observed that CCR8 was expressed by tumor cells in CTCL and other peripheral T-cell lymphomas. CCR8 is expressed by skin resident-memory T cells which are believed to be the tumor cell-of-origin in mycosis fungoides. Domain Therapeutics (DT) showed the in vitro efficacy of their proprietary anti-CCR8 mAb DT7012 in the depletion of CTCL cells. Therapeutic depletion of CCR8-expressing cells by DT-7012 could eliminate tumor cells and activate the anti-tumor immunity in CTCL. We hypothesize that treatment with DT-7012 is effective in the treatment of relapsed or refractory (R/R) CTCL as advanced MF and SS.