Reader Responses: How would you treat a patient with aggressive systemic mastocytosis?

Here’s how readers responded to a You Make the Call question about treatment of bone manifestations and transplantation for systemic mastocytosis.

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Since she is young, I’d recommend prepping her for alloHCT (I would not wait more than 5 years). Zoledronic acid is a good choice for the bone pain.

Adel Al-Marzouki, MBBS
Jeddah, Saudi Arabia

I would initially treat the patient with cladribine or midostaurin, depending on her access to these medications. Then I would proceed to alloHCT with myeloablative conditioning, as the data are much more robust regarding long-term remission with myeloablative conditioning.

Suchitra Krishnamurthy, MBBS, MRCP, FRCPath
Whangarei, New Zealand

The role of alloHCT in patients with advanced systemic mastocytosis is based on case series. Transplant may be considered for patients whose disease fails to respond to, or relapses after, a tyrosine kinase inhibitor (TKI), who have an underlying hematological neoplasm that does not respond to a TKI, who have a high-risk karyotype including monosomy 7 or a complex karyotype or high-risk mutations including RUNX1, SRSF2, and ASXL1. Ideally, the patient should be young and fit with a matched related donor available, but these factors should not preclude transplant.

Hamza Hashmi, MD, MBBS
Charleston, SC

I would treat the patient with avapritinib, which has outstanding results compared to midostaurin. There are trials for both indolent and aggressive systemic mastocytosis in progress. I would definitely complete HLA typing, but I find my patients with ASM are very heterogeneous. It would be helpful to know about her cladribine exposure and whether she’s been maxed out on mast cell stabilizers.

Martina Trinkaus, MD, FRCPC
Toronto, Ontario, Canada

I would treat the patient with midostaurin until progression, then cladribine until progression, then alloHCT if a good donor is available.

Robert John Ellis, MD
Springfield, MO

Cromolyn sodium is not necessarily the best agent for controlling this patient’s bone pain due to mastocytosis. I would start her on a regimen of H1 and H2 blockers, in combination with a leukotriene inhibitor or mast cell stabilizer (montelukast, ketotifen, etc.), to see if reducing the activity of the mast cells reduces the pain. If she continues to be symptomatic, I would pursue a clinical trial with avapritinib long before considering alloHCT. I recommend bisphosphonate therapy for all patients with mastocytosis and osteoporosis, but the choice of which bisphosphonate usually depends on insurance coverage.

Laura W. Bickel, APRN
Salt Lake City, UT