A case study published in Leukemia and Lymphoma described a patient with a diagnosis of Waldenstrm Macroglobulinemia (WM) that had subsequently undergone histological transformation to refractory high grade B-cell lymphoma and was successfully treated with CD19-targeted chimeric antigen receptor (CAR)-T cell therapy.1

WMis a type of B-cell non-Hodgkin lymphoma(NHL), typically characterized by overproduction of monoclonal immunoglobulinM, as well as infiltration of malignant lymphoplasmacytic cells into the bonemarrow.

Although considered incurable, WM often follows an indolent course andsome patients can be asymptomatic for long periods. Rarely, the diseasetransforms into a more aggressive form of NHL that has been associated with apoor prognosis.

The patient described in the case studywas a 71-year-old man who was first diagnosed with WM in 1998. The patient wasmonitored without undergoing active treatment for a period of 12 years, atwhich time he developed anemia and splenomegaly. At that time, he underwenttreatment with 6 cycles of fludarabine and rituximab and achieved a partial response totreatment. Following a worsening of symptoms 4 years later, the patient wastreated with 6 cycles of bendamustine and rituximab.

Biopsyof an enlarged cervical lymph node performed at that time revealed high-gradeB-cell lymphoma that was clonally related to the previously seenlymphoplasmacytic infiltrate, consistent with transformation.

Thepatient subsequently achieved a complete response to 6 cycles of rituximab,cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) plus ibrutinibfollowed by 6 months of ibrutinib maintenance therapy that lasted for 18months.

Salvagetherapy included 2 cycles of rituximab, dexamethasone, cytarabine, cisplatin(R-DHAP) followed by 1 cycle of rituximab plus high-dose cytarabine, followedby autologous stem cell transplantation several months later.

Asthe patients disease was considered to be chemorefractory based on subsequent imagingand pathological analyses, he was treated with axicabtagene ciloleucel, aCD19-targeted CAR-T cell therapy currently approved for the treatment of adultpatients with relapsed or refractory large B-cell lymphoma, including high gradeB-cell lymphoma, after 2 or more lines of systemic therapy.2

Althoughthe patient experienced pancytopenia, grade 1 cytokine release syndrome, andgrade 1 neurotoxicity following CAR-T therapy, he achieved a complete response1 month following treatment.

Notably,there was no evidence of either underlying WM or transformed disease at 6 and 12months follow-up.

Thestudy authors noted that longer term follow up in this patient will beinformative, as late relapses have occurred even in patients who achieve a deepresponse after transplant. CAR-T cell therapy may be an effective treatment forrelapsed or refractory WM that has not yet undergone histologicaltransformation, as CD19 is almost universally expressed on lymphoplasmacyticlymphoma cells. The researchers concluded that further analysis of this iswarranted in the context of clinical trials.

References

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Benefit of CD19-Targeted CAR-T Therapy in Patients With Transformed Waldenstrm Macroglobulinemia - Cancer Therapy Advisor