SOLAR: Efficacy and Safety of Cobomarsen (MRG-106) vs. Active Comparator in Subjects With Mycosis Fungoides

SOLAR: A Phase 2, Randomized, Open-label, Parallel-group, Active Comparator, Multi-center Study to Investigate the Efficacy and Safety of Cobomarsen (MRG-106) in Subjects With Cutaneous T-Cell Lymphoma (CTCL), Mycosis Fungoides (MF) Subtype

The main objective of this clinical trial is to study the efficacy and safety of cobomarsen (also known as MRG-106) for the treatment of cutaneous T-cell lymphoma (CTCL), mycosis fungoides (MF) subtype. Cobomarsen is designed to inhibit the activity of a molecule called miR-155 that may be important to the growth and survival of MF cancer cells. The study will compare the effects of cobomarsen to vorinostat, a drug that has been approved for the treatment of CTCL in the United States and several other countries.

Participants in the clinical trial will be randomly assigned to receive either weekly doses of cobomarsen by injection into a vein or daily oral doses of vorinostat. Participants will continue on their assigned treatment as long as there is no evidence of progression of their cancer. The effects of treatment will be measured based on changes in skin lesion severity, as well as the length of time that the subject's disease remains stable or improved, without evidence of disease progression. The safety and tolerability of cobomarsen will be assessed based on the frequency and severity of observed side effects.

Participants assigned to receive vorinostat who experience progression of their disease during their participation in this study may have the option to be treated with cobomarsen in an open-label, crossover arm of the same study if they meet the entry criteria for that part of the study.

Study Design:

Subjects will be randomly assigned in a 1:1 ratio to receive either cobomarsen or vorinostat. Approximately 126 subjects (63 per arm) are expected to be enrolled. Cobomarsen will be administered in the clinic by 2-hr intravenous infusion on Days 1, 3, 5 and 8, and weekly thereafter. Vorinostat will be dispensed to study subjects and taken as a daily oral dose according to the manufacturer's labeled dosing instructions. Treatment will continue until the subject becomes intolerant, develops clinically significant side effects, progresses, or the trial is terminated. An interim analysis will be conducted after approximately 40 subjects have been followed for a minimum of approximately 6 months. Enrollment will be suspended until the completion of the interim analysis.

Key Inclusion Criteria:

• Biopsy-proven CTCL, MF subtype
• Clinical stage IB, II, or III, with staging based on screening assessments
• Minimum mSWAT score of 10 at screening
• Receipt of at least one prior therapy for CTCL

Key Exclusion Criteria:

• Previous enrollment in a cobomarsen study
• Prior therapy with vorinostat or other HDAC inhibitors, or contraindication to an HDAC inhibitor
• Sézary syndrome or mycosis fungoides with B2 involvement, defined as documented history of B2 and/or B2 staging at screening
• Evidence of large cell transformation
• Lymph node involvement at screening, unless radiologically or histologically confirmed to be nonmalignant
• Visceral involvement related to MF at screening