The BENeFiTS Trial in Beta Thalassemia Intermedia

Overview

Beta-thalassemias and hemoglobinopathies are serious inherited blood diseases caused by abnormal or deficiency of beta A chains of hemoglobin, the protein in red blood cells which delivers oxygen throughout the body.The diseases are characterized by hemolytic anemia, organ damage, and early mortality without treatment. Increases in another type of (normal) hemoglobin, fetal globin (HbF), which is normally silenced in infancy, reduces anemia and morbidity. Even incremental augmentation of fetal globin is established to reduce red blood cell pathology, anemia, certain complications, and to improve survival. This trial will evaluate an oral drug discovered in a high throughput screen, which increases fetal globin protein (HbF and red blood cells expressing HbF)and messenger ribonucleic acid (mRNA) to high levels in anemic nonhuman primates and in transgenic mice. The study drug acts by suppressing 4 repressors of the fetal globin gene promoter in progenitor cells from patients. The drug has been used for 50 years in a combination product for different actions - to enhance half-life and reduce side effects of a different active drug- and is considered safe for long-term use. This trial will first evaluate 3 dose levels in small cohorts of nontransfused patients with beta thalassemia intermedia. The most active dose will then be evaluated in larger subject groups with beta thalassemia and other hemoglobinopathies, such as sickle cell disease.

The study will first evaluate 3 doses of the investigational drug which are considered safe with chronic use in a combination therapeutic used widely for a different disease in Europe and Canada. The doses to be studied are human equivalent doses of doses that are active in nonhuman primates in inducing high level fetal globin messenger ribonucleic acid (mRNA), protein, and proportions of red blood cells expressing fetal globin protein (F-cells). Additive effects are observed with hydroxyurea in sickle cell patients' cells in vitro. The study will first evaluate the study therapeutic in male and female patients who are 18 years and older. After a screening period to obtain baseline medical and laboratory data, the study drug will be taken by mouth once per day, every other day. The first dose will be taken in a clinical unit, and thereafter will be taken at home for 12 weeks. Laboratory tests, physical exams, and tolerability will be assessed 6 times over 4 months, including for one month after completion of dosing. The cohorts will be enrolled sequentially. Each new cohort will begin after the prior lower dose cohort has received 2 weeks of treatment without serious adverse events related to the study drug. The dose that increases fetal globin assays to the highest degree will be evaluated in a larger group of subjects with beta thalassemia intermedia and a groups with sickle cell disease. Other regimens or test doses may be added as needed to identify an active dose and regimen. The study drug is expected to be safe when added to most other medications used to treat thalassemia.