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 mastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults., 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 activationMast cell activation Describes when mast cells release histamine and other mediators into the blood stream in response to an allergen or other trigger. This leads to symptoms like fatigue, rash and, in severe cases, anaphylaxis.,” 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 tryptaseTryptase A protein enzyme that is primarily produced by mast cells and stored in small pockets within the cells, known as granules. High levels of tryptase are a key indicator of SM. 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 cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. 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 biopsyBone marrow biopsy A procedure to collect a sample of bone marrow using a needle. Often used to examine the characteristics of mast cells and diagnose SM. fulfilled the diagnostic criteria for SM. The patient began treatment with antihistaminesAntihistamines Medications that block the effects of histamine, the chemical found in mast cells that is responsible for many of the symptoms of SM, as well as many allergic reactions. ketotifen, omalizumab for anaphylaxisAnaphylaxis A severe allergic reaction that can turn fatal without treatment. Patients with SM are at a higher risk of developing 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.
