A new treatment option for malignant blood cancers of T lymphocytes, such as LGL leukemia and cytotoxic lymphomas

Malignant diseases of T lymphocytes, a subtype of white blood cells, are rare overall. At the same time, this term encompasses a relatively large group of very diverse diseases. In addition to T cells, these diseases also affect, for example, so-called natural killer cells (NK cells). While the cause of LGL leukemia is not fully understood—genetic changes are suspected—cytotoxic lymphomas may be associated with previous infections. The course of the disease also varies among the different conditions: LGL leukemia is usually chronic and progresses slowly, while cytotoxic lymphomas are often aggressive and respond less well to treatment. In general, unlike other blood disorders, there are currently few targeted therapies available. Standard treatments include chemotherapy, radiation therapy, and stem cell transplantation. DR-01 is a novel antibody that specifically binds to the surface marker CD94 on diseased cells. Once bound, it is intended to destroy the diseased cells.

This study investigates whether the new drug DR-01 is effective in patients with malignant T-cell disorders. The study is structured in two phases: In Phase 1 (dose escalation), DR-01 is first administered at a low dose and then at a higher dose, while its safety and efficacy are evaluated. In Phase 2 (dose expansion), the determined optimal dose will be tested in additional participants to gather further data on efficacy and tolerability. DR-01 is an experimental drug and is not available outside of clinical trials. All patients will receive the study medication—in specific groups depending on their type of disease. Once the optimal dose has been determined, the treatment automatically moves to Phase 2. The total duration of the study is approximately 26 months.

Eligible participants include women and men aged 18 and older with LGL leukemia or cytotoxic lymphomas. Due to the many subtypes, here is a list: Primary cutaneous gamma-delta T-cell lymphoma; Primary cutaneous CD8⁺ aggressive epidermotropic T-cell lymphoma; Hepatosplenic T-cell lymphoma; Subcutaneous panniculitis-like T-cell lymphoma; Aggressive NK-cell leukemia; Systemic EBV-positive T-cell lymphoma (in cases of CD8 positivity); Hydroa vacciniformis-like lymphoproliferative disorder; Extranodal NK/T-cell lymphoma, nasal type; Enteropathy-associated T-cell lymphoma; Monomorphic epitheliotropic intestinal T-cell lymphoma; Cytotoxic peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), with CD8⁺ or CD56⁺ and cytotoxic markers; Cutaneous peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), with CD8⁺ or CD56⁺ and cytotoxic markers. To be eligible for participation, patients must have received at least one prior systemic therapy; for cytotoxic lymphomas, at least two. Prior to the start of the study, no corticosteroid treatment may be administered for a specific period of time—depending on the dosage. Additionally, participants must not have any active infection or central nervous system involvement. A history of stem cell therapy is not an exclusion criterion, but it should have occurred sufficiently long ago.