While there have been some advancements in the management of mast cell leukemia (MCL), an advanced form of systemic mastocytosis (SM), expected outcomes remain poor, according to a study recently published in the Journal of Hematology.
MCL is an aggressive, cancerous form of SM that has long been associated with a poor prognosis, with average overall survival estimated to be about a year and a half. It accounts for less than 1% of all SM cases.
MCL is mostly seen in adults between 40 to 60 years old. The most common subtype is primary MCL, which is when MCL develops in patients who don’t have another mast cell disorder; this subtype accounts for up to 70% of cases, and is more aggressive. Secondary MCL describes when the disease develops from preexisting SM, or another mast cell disorder.
There are many possible signs and symptoms in MCL, depending largely on the organs affected. What are collectively known as “constitutional symptoms” are common, such as fatigue, fever, unintentional weight loss and night sweats. In acute MCL, when symptoms worsen suddenly, common signs are skin blisters, diarrhea and abdominal pain, bone weakness and pain, cognitive impairment and neuropsychiatric symptoms, an enlarged liver, enlarged spleen and lymph node disease.
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The authors’ review of available MCL therapies concluded that more treatment options are needed. “Currently, treatment options for MCL remain limited and the prognosis is generally poor, highlighting the need for further research into treatments targeting the underlying molecular mechanisms,” they noted.
The first-line treatments of MCL include a type of therapy known as tyrosine kinase inhibitors, such as midostaurin and avapritinib. Chemotherapy is typically prescribed in MCL, while immunomodulatory therapies are sometimes offered to support the immune system. A relatively small percentage of patients with high-risk disease may qualify for allogeneic hematopoietic stem cell transplantation, which may improve long-term survival but is associated with significant risks.
Experimental therapies have shown some promise in early studies. An example is bezuclastinib, which was developed to treat advanced SM; early studies show that it is well-tolerated and resulted in improved disease parameters. Ripretinib is another experimental therapy; it was initially designed to treat gastrointestinal cancers but is currently being studied for possible use in MCL.
“Much more research and advancements are necessary before developing treatments that could further improve median [overall survival],” the review study concluded.
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