The status is given to treatments for rare diseases. It accelerates the regulatory approval process and provides the therapies’ developers with incentives to keep working on them.
T-cell lymphomas account for about 15 percent of all non-Hodgkin’s lymphomas in the United States. One of the most common is cutaneous T-cell lymphoma, a general term for T-cell lymphomas that involve the skin.
CTCL can also attack the blood, the lymph nodes, and other organs. Symptoms can include dry skin, itching, a red rash, and enlarged lymph nodes.
MRG-106 inhibits the small RNA molecule miR-155, which is found at high levels in the malignant T-cells of many CTCL patients. MiR-155 plays a role in various normal and malignant cell processes, and may enhance the progression and survival of CTCL cancer cells.
In preclinical-trial studies, MRG-106 restored normal function in lymphoma cells and reduced the proliferation of abnormal cells.
MiRagen is conducting a Phase 1 trial (NCT02580552) to assess the tolerability and safety of MRG-106 in patients with a type of CTCL known as mycosis fungoides.
The study will be conducted in two parts. In Part A, MRG-106 will be injected directly into CTCL skin lesions. In Part B, it will be injected to other parts of the skin or administered intravenously.
MiRagen said the measuring sticks for the primary trial goals of establishing MRG-106’s safety and tolerability will be physical exams, laboratory tests, electrocardiograms, and number and severity of adverse events.
Other goals are to see how well the blood absorbs and clears MRG-106, and to understand how CTCL skin lesion cells respond to MRG-106.
MiRagen will present the results of the trial at the American Society of Clinical Oncology Annual Meeting in Chicago, June 2-6.
In the presentation, titled “Phase 1 trial evaluating MRG-106, a synthetic inhibitor of microRNA-155, in patients with cutaneous t-cell lymphoma (CTCL),” researchers will report initial results from the first 15 patients. The treatment was well tolerated and did not cause adverse reactions, the team said.
All four of the trial patients who completed treatment experienced at least a 50 percent reduction in a lesion severity measurement known as the Composite Assessment of Index Lesion Severity. Patients’ response to the therapy lasted through the end of the evaluation, which in some cases was 28 days after treatment and in others 35.
The trend was for the lesions’ density and depth to decrease after treatment, examinations indicated. Gene expression analysis also showed a reduction in some disease biomarkers, or signs of a disease’s presence.
Among the eight patients injected with MRG-106 in locations outside lesions, three achieved a 39 percent decrease in the severity of their lesions — a maximum. That indicated a significant response, researchers said.
Earlier this year, the U.S. Food and Drug Administration granted orphan drug status to MRG-106 for the treatment of mycosis fungoides, the most common subtype of CTCL.
“The European orphan drug designation for MRG-106 is another regulatory milestone which we believe further validates the medical need for novel therapies in the treatment of CTCL,” Dr. William S. Marshall, miRage’sn president and chief executive officer, said in a press release. “MRG-106 has now been granted orphan drug designation from the FDA and the EC [European Commission], and we look forward to continuing to develop this product candidate as a potential therapy for patients suffering from this disease.”