12. December 2011 16:07
Myleofibrosis is a rare bone-marrow disease that leads to anemia and thrombocytopenia. As the disease progresses, bone marrow is replaced by scar tissue, which gets to be stored elsewhere in the body, notably, in the spleen and in the liver. Spleen and liver enlargement result as a consequence.
Myleofibrosis results from the ineffective regulation of two enzymes, namely, JAK-1 (Janus-Associated Kinase - 1) and JAK 2. Ruxolitinib, a new medicine to treat the disease, inhibits JAK-1 and JAK-2, and is the first JAK inhibitor to be approved by the US Food and Drug Administration (FDA). Designated an orphan drug (a drug to treat a disease that fewer than 200,000 people in the US suffer from), Ruxolitinib was cleared on a priority basis under a special review programme that provides for priority review of drugs that are (i) significantly superior to other existing therapies or (ii) provide treatment when other therapies are absent. Ruxolitinib has been approved for treating patients who have intermediate or high-risk myelofibrosis, according to its manufacturer, who says also that 80% to 90% of myelofibrosis patients fall in this category.
Reduction of spleen size by more than 35% occurred in a greater proportion of test subjects who were on Ruxolitnib as compared to those on placebos or on best-available therapies (hydroxyurea or glucocorticoids). A 50% abatement of other symptoms associated with the disease - abdominal discomfort, night sweats, itching or bone and muscle pain, was similarly more prevalent among the Ruxolitnib-ingesting test subjects.
In most cases of patients on Ruxolitnib, spleen size decreased and symptoms abated within a month of treatment. By contrast, most of those on placebos experienced worsening of symptoms and enlargement of the spleen, according to the principal investigator in one of the two trials - Srdan Verstovsek, MD, PhD, of the University of Texas M.D. Anderson Cancer Center in Houston. Another analyst, Richard Pazdur, M.D. - the FDA’s Director of Oncology, said that the drug represents an instance of how better scientific understanding makes possible a more focused intervention.