A new case study reported promising results for a man who started experimental therapy for persistent severe systemic mastocytosis (SM) symptoms that did not respond well to other treatment, according to a report in Frontiers in Allergy.
The patient enrolled in a clinical trial for avapritinib and has significantly improved after his symptoms persisted despite undergoing other treatment options.
“When we started the trial drug for mastocytosis, I was nervous about side effects but have been thankful for it ever since,” the patient stated. “Things are not perfect, but I feel like I am getting my life back, which is a great thing.”
What is SM?
Systemic mastocytosis (SM) is a rare hematological disease characterized by mast cells that are overactive and accumulate in different parts of the body such as the bone marrow, liver, spleen, gastrointestinal tract and lymph nodes.
“Eighty percent of all cases of SM are indolent, and the clinical case presented focuses on challenging diagnostic and treatment considerations indolent systemic mastocytosis (ISM) may present with a range of signs and symptoms, including life-threatening acute episodes of mast cell activation,” the researchers stated.
Read more about SM treatment and care
The case involved a 44-year-old man with a history of a previous lumbar fracture, recurrent loose stools and acid reflux, who presented with persistent lumbar pain after a fall at work. The patient sought assistance at a specialized spine center where a neurologist diagnosed a compression fracture in the third thoracic vertebrae. Additional studies determined that the patient had osteoporosis, a rare diagnosis in men under 60.
Endocrinologic consultation ruled out other causes of osteoporosis such as celiac disease and parathyroid disease. An elevated tryptase level raised the suspicion of SM, and the patient was referred to a mastocytosis center.
Further interrogation revealed that the patient had a history of severe anaphylactic reactions after hornet sting episodes, as well as recurrent flushing episodes due to heat and exercise. Persons with SM are at increased risk of developing severe allergic reactions after insect stings, and flushing is a common consequence of increased mast cell activity. Other SM-suggestive symptoms included difficulty concentrating (mental fog), depression and anxiety.
Genetic testing was positive for a KIT D816V mutation, and a bone marrow biopsy fulfilled the diagnostic criteria for SM. The patient began treatment with antihistamines ketotifen, omalizumab for anaphylaxis prevention and zoledronic acid to treat osteoporosis. The patient also received psychiatric assistance for depression and anxiety.
The patient returned to work two years after the fracture, but his lumbar pain, flushing and mental fog persisted. Shortly after, he had a child, leading the family to seek other alternatives to improve his quality of life. The patient enrolled in a clinical trial for avapritinib and improved.
