Preliminary Results of a Phase 1 Trial Evaluating MRG-106, a Synthetic microRNA Antagonist (LNA antimiR) of microRNA-155, in Patients with CTCL

• Published in: Blood 2016-12, Vol.128 (22), p.1829-1829
• Main Authors: Querfeld, Christiane, Pacheco, Theresa, Foss, Francine M., Halwani, Ahmad S., Porcu, Pierluigi, Seto, Anita G, Ruckman, Judy, Landry, Michele L, Jackson, Aimee L, Pestano, Linda A, Dickinson, Brent A, Sanseverino, Mark, Rodman, David M, Gordon, Gilad, Marshall, William
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V128.22.1829.1829

Introduction and Objectives: microRNAs are small, non-coding RNAs that regulate expression of multiple genes which impact physiological processes and cellular phenotypes. miR-155-5p is a well-described onco-miR with a strong mechanistic link to cutaneous T-cell lymphoma (CTCL). A LNA-modified oligonucleotide inhibitor of miR-155-5p, MRG-106, was selected based on its ability to de-repress canonical miR-155-5p targets in multiple mycosis fungoides (MF) cell lines in vitro. In preclinical models, MRG-106 showed significant pharmacodynamic activity without requiring additional formulation. The objective of this first-in-human study is to evaluate the safety, tolerability, pharmacokinetics and preliminary efficacy of MRG-106 in patients with mycosis fungoides (MF). Methodology: This Phase 1 trial employs a dose-escalation design to evaluate both intratumoral and subcutaneous administration of MRG-106 at doses of 75 mg and up to 900 mg per injection, respectively. Patients were required to be ≥ 18 years old, have a confirmed diagnosis of MF, be clinical stage I-III with plaques or tumors, be on a stable treatment regimen or without any concomitant therapy for MF, and have no other major illness. The first 6 patients were dosed with four or five 75 mg intratumoral injections of MRG-106 over 2 weeks. In addition, 4 patients received saline injections in a second lesion on the same schedule. Skin biopsies were taken from MRG-106 and saline treated lesions for molecular, bioanalytical, and histological analyses, before the first dose and after the last dose. Results: Six patients (5M/1F, median age 61 years, 5 Caucasian/ 1 African-American) were dosed intratumorally. All tolerated the administrations well with only minimal erythema at the site of injection noted in one patient. One patient was discontinued from the trial due to rapid progression of disease, which was considered not related to the study drug. There were no clinically significant adverse events or laboratory abnormalities. To date, the first cohort of 6 patients has either completed the dosing period (5 patients) or discontinued due to progressive disease (1 patient). All patients showed a reduction in the baseline Composite Assessment of Index Lesion Severity (CAILS) score in both MRG-106-treated and saline-treated lesions. The maximal reduction was on average 55% [range: 33% to 77%] in the MRG-106 treated lesion and 39% [range:13% to 75%] in the saline treated lesions). In all the subjects that com