A hematologist detailed several cases of systemic mastocytosis (SM) that highlighted the need for diligence in diagnosing and managing the treatment of patients with indolent SM, according to a paper published recently in Blood.
“A detailed history and examination is the cornerstone of good clinical practice,” said Deepti H. Radia, a consultant hematologist at Guys & St Thomas’ NHS Foundation Trust in London. “Systemic mastocytosis with associated hematologic neoplasm (SM-AHN) patients are heterogenous with complex dual pathologies and unpredictable clinical outcomes. Each patient is unique, needing personalized management plans.”
Radia’s paper presented several real-life cases in which indolent SM progressed to SM-AHN, highlighting the need for regular monitoring after an indolent SM diagnosis. Common manifestations of disease progression included weight loss, anemia and low platelet counts (thrombocytopenia), Radia said.
In some cases, performing genetic testing through next-generation sequencing (NGS) earlier could have led to earlier diagnosis and treatment. At the time, NGS was not routinely done after diagnosis of indolent SM, but Radia said she would now perform it in cases with features suggestive of SM-AHN, such as persistent monocytosis.
In two of the five presented cases, avapritinib led to significant clinical improvement. Avapritinib targets the KIT D816V mutation, and its efficacy and safety for patients with SM has been demonstrated in multiple trials. Two patients required treatment with experimental drugs (bezuclastinib and midostaurin) in clinical trials, leading to clinical improvement.
Two patients underwent a hematopoietic stem-cell transplant (HSCT) and were doing well 15 months post-transplant; Radia was still evaluating a third patient who may have needed an HSCT at the time she wrote her paper. She highlighted the potential of new tyrosine kinase inhibitors to enable HSCT as a curative option.
“The new, potent TKIs and potential of combination or sequential targeted therapies demonstrating deeper and complete responses may enable some patients to proceed to allogeneic transplantation as a curative option,” Radia said. ”Embedding prognostic scores and mutational monitoring, utilizing objective response assessment criteria applicable in daily practice will facilitate improved outcomes.”
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