- On Thursday, the Food and Drug Administration approved a new treatment for certain adults with a type of bone marrow cancer called myelofibrosis.
- An uncommon cancer, myelofibrosis causes scarring in the bone marrow that often leads to severe anemia, among other health problems. The new treatment, known scientifically as momelotinib, is now the only medicine approved by the FDA to address the main hallmarks of myelofibrosis in both recently diagnosed and previously treated patients with anemia.
- GSK, which acquired momelotinib through the nearly $2 billion purchase of Sierra Oncology last year, plans to sell the drug under the brand name Ojjaara. GSK has said it sees “significant growth potential” in Ojjaara, though some analysts have questioned how impactful the drug will be to rival therapies sold by Incyte and Bristol Myers Squibb.
In buying Sierra, GSK made a bet that Ojjaara would be a more attractive treatment option than the other, currently available myelofibrosis therapies.
Incyte’s Jakafi and Bristol Myers’ more recently approved Inrebic have been on the market for years. Clinical trials have shown that both drugs can improve the symptoms associated with myelofibrosis. Yet, they sometimes also worsen anemia. Myelofibrosis patients with severe anemia often experience fatigue, weakness and shortness of breath, and may require frequent blood transfusions or, in some cases, stem cell transplants.
Ojjaara works in a somewhat similar way to Jakafi and Inrebic. All three medicines act on “JAKs,” or Janus kinases — enzymes that perform a variety of important roles in the body, including the regulation of cell growth and immune system activity.
However, Ojjaara also inhibits a protein called ACVR1, which itself has several biological functions and is found, among other places, in the bones. GSK believes this blocking of the ACVR1 protein is what leads its drug to have an effect on anemia.
A key late-stage clinical trial found that a significantly greater percentage of myelofibrosis patients who received Ojjaara rather than an older drug experienced a 50% or greater reduction in symptoms related to their disease. Ojjaara also appeared to improve other health measures, such as reducing the size of patients’ spleens and their need for blood transfusions.
“With momelotinib we have the potential to establish a new standard of care for myelofibrosis patients with anemia,” said Ruben Mesa, executive director at the Atrium Health Wake Forest Baptist Comprehensive Cancer Center, in a Thursday statement from GSK.
The FDA initially agreed to review the approval application for Ojjaara in August 2022, and expected to issue a verdict no later than June 16. But the agency pushed back its approval deadline by three months — a decision that, according to GSK, was made to review additional data the company had submitted.
GSK didn’t specify what kind of data were added, but at least one Wall Street analyst speculated that the new information may have been meant to support broader use of the drug if approval were granted. Notably, the FDA cleared Ojjaara for use in myelofibrosis patients with anemia regardless of whether they had received prior therapies for their disease.
Andrew Berens, an analyst at Leerink Partners who covers Incyte, wrote in a note to clients Monday that Ojjaara, with its broad labeling and apparent effects on anemia, “could represent meaningful competition” to Jakafi.
Last year, Incyte recorded $2.4 billion in net revenue from Jakafi, which is also approved to treat two other diseases.