In a press release on the company website, biopharmaceutical company AbbVie shared that preliminary data was available regarding navitoclax, an investigational therapy, for individuals with primary myelofibrosis. The data comes from the Phase 2 REFINE clinical trial. Within the trial, researchers evaluated the safety, efficacy, and tolerability of navitoclax alongside ruxolitinib in patients who had not previously been treated with JAK inhibitors.
According to AbbVie, navitoclax is a small-molecule BCL-XL/BCL-2 inhibitor. It is administered orally. The treatment works by blocking enzymes which help protect the survival of cancer cells.
The newly available trial data comes from the 3rd cohort within the REFINE trial, which consisted of 32 patients. Navitoclax and ruxolitinib treatment helped to reduce spleen volume in 78% of individuals, symptoms, and bone marrow fibrosis. Additionally, the therapeutic combination also helped address and improve anemia in some patients.
Altogether, navitoclax was found to be relatively safe and well-tolerated. However, some adverse reactions did occur. These included anemia (low red blood cell count), thrombocytopenia (low platelet count), and neutropenia (low neutrophils).
Currently, there are specific genes indicated in the development of a rare leukemia and bone marrow disorder called (primary) myelofibrosis: JAK2, CALR, and MPL. In fact, about 50%, 20%, and 10% of individuals with myelofibrosis respectively have mutations in these genes. A single hematopoietic stem cell’s DNA is changed, causing the creation of continuous copies. As healthy cells are pushed out of the bone marrow, and scarring (fibrosis) occurs, the bone marrow is unable to produce enough blood cells. Myelofibrosis is more common in individuals aged 50+. However, in children, myelofibrosis often occurs before age 3, and occurs 2x more often in girls than boys. When symptoms manifest, they can include:
- Anemia (low red blood cell count)
- Fever and night sweats
- Pallor (pale skin)
- Headaches and/or lightheadedness
- Excessive bruising and bleeding
- Fatigue and general weakness
- Enlarged spleen and liver
- Shortness of breath
- Bone and joint pain
- Frequent infections