New Delhi: Concerns have been expressed about the appropriateness of current FDA-approved myelofibrosis treatments, primarily due to their negative associations with anemia. In response to these concerns, the FDA has significantly augmented the allocation of ODDs for drugs indicated for myelofibrosis in recent years. According to GlobalData, a total of 11 ODDs have been granted since 2014, with eight of them bestowed after 2020.
Myelofibrosis, an aggressive form of blood cancer characterised by the accumulation of scar tissue in the bone marrow, disrupts the normal production of blood cells. This condition is considered rare, with approximately 1.5 cases reported per 100,000 people annually in the US, as reported by the National Organisation for Rare Disorders (NORD).
Jasper Morley, Drugs Intelligence Analyst at GlobalData, said, “The high level of ODD awarding indicates the heightened focus by the FDA to explore alternative mechanisms of action, to tackle this unmet need within myelofibrosis. Currently, there are four FDA-approved innovator drugs for this condition, all of which are Janus kinase (JAK) inhibitors.
“Although effective in treating myelofibrosis, this mechanism of action is well known for myelosuppression, which can induce and worsen symptoms of anemia, reducing oxygen circulation throughout the body. As roughly half of patients are already anemic at diagnosis, there is a crucial need for approved myelofibrosis treatments that benefit this patient population.”
Since 2020, eight ODDs have been awarded by the FDA, which is more than double the number awarded over the preceding four years. 2022 saw a surge in the number of ODDs awarded by the FDA, with four being awarded, double the number of ODDs awarded in the previous peak years of 2019 and 2020, which both featured two.
“Only two out of the 12 myelofibrosis drugs that have received ODD from the FDA since 2014 act via JAK inhibition. This demonstrates the shift in regulatory focus from the FDA away from this anemia-inducing mechanism of action. The remaining 10 drugs feature a variety of treatment mechanisms, with no two drugs sharing similar mechanisms of action,” adds Morley.
Merck & Co’s Reblosyl (luspatercept) acts via growth/differentiation factor (GFD) 11 and 8 inhibition. This recombinant fusion protein was awarded ODD by the FDA in January 2020 and is currently in Phase III for anemia-associated myelofibrosis.
Morley concluded by stating, “The recent increase in the awarding of ODDs by the FDA highlights the enhanced effort to promote the development of novel myelofibrosis drugs that feature mechanisms of action that do not induce or worsen anemia. This increase in awarded designations should lead to a greater number of approved treatments that offer greater benefit regarding this unmet area of myelofibrosis therapy.”
