Safety, Tolerability and Pharmacokinetics of MRG-106 in Patients With Mycosis Fungoides (MF), CLL, DLBCL or ATLL

Objectives of this clinical trial are to evaluate the safety, tolerability, pharmacokinetics and potential efficacy of the investigational drug, cobomarsen (MRG-106), in patients diagnosed with certain lymphomas and leukemias, including cutaneous T-cell lymphoma (CTCL) \[mycosis fungoides (MF) subtype\], chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL) \[activated B-cell (ABC) subtype\], and adult T-cell leukemia/lymphoma (ATLL). Cobomarsen is an inhibitor of a molecule called miR-155 that is found at high levels in these types of cancers and may be important in promoting the growth and survival of the cancer cells. Participants in the clinical trial will receive weekly doses of cobomarsen administered by injection under the skin or into a vein, or by injection directly into cancerous lesions in the skin (for CTCL only). Blood samples will be collected to measure how cobomarsen is processed by the body, and other measurements will be performed to study how normal and cancerous cells of the immune system respond when exposed to cobomarsen.

Study Design: * Part A: Cohorts of 3-6 patients diagnosed with MF will receive up to five intratumoral injections of cobomarsen over a period of up to 15 days with follow-up for an additional 20 days, beginning with the maximum deliverable intratumoral dose. Doses may be decreased in subsequent cohorts to determine the minimum pharmacodynamically active dose. * Parts B-F: Patients in these parts of the study will be diagnosed with MF (Parts B and C), CLL (Part D), DLBCL (Part E), or ATLL (Part F). All patients will receive subcutaneous or intravenous cobomarsen (or a combination of systemic and intratumoral administration for MF patients only) on Days 1, 3 and 5, and will continue dosing on a weekly schedule until the patient becomes intolerant, develops clinically significant side effects, progresses, or the trial is terminated. Doses administered will not exceed a dose level predicted to be safe based on all prior treatment experience with the drug. Patients in Part B may continue on a stable background therapy for their disease during their treatment with cobomarsen, while patients in Parts C-F will be treated with cobomarsen alone.