GSK (LSE:GSK) has secured orphan drug designation from both the US Food and Drug Administration and the European Medicines Agency for momelotinib, its already-approved blood cancer treatment, in a rare and life-threatening inflammatory disorder called VEXAS syndrome.
VEXAS, which stands for vacuoles, E1 enzyme, X-linked, autoinflammatory and somatic, is a progressive condition in which the immune system attacks the body's own blood-forming cells, causing severe inflammation and blood abnormalities. It currently has no approved therapies and carries a five-year mortality rate of 30% to 40%.
Orphan drug designation is granted by regulators to medicines targeting rare diseases, giving developers financial incentives and an extended period of market exclusivity to encourage investment in conditions that would otherwise attract little commercial interest.
The designations were supported by retrospective case studies suggesting that JAK inhibitors, a class of drugs that block inflammatory signalling pathways, may be effective in VEXAS, as well as a case report showing clinical benefit from momelotinib specifically, including symptom improvement, reduced inflammation and better blood-related outcomes.
Momelotinib, sold under the brand names Ojjaara and Omjjara, is already approved in the US, European Union, UK and Japan for myelofibrosis, a bone marrow cancer, in patients with anaemia.
GSK said a planned clinical trial called ATLAS will evaluate momelotinib's efficacy and safety in VEXAS patients and will underpin planned regulatory submissions globally.
