Some patients with aggressive leukemic nonnodal mantle cell lymphoma (L-NN-MCL) respond very well to combination therapy with rituximab and ibrutinib, according to two case reports.
Both patients, who had aggressive L-NN-MCL and P53 abnormalities, remain free of disease 18 months after treatment with rituximab/ibrutinib and autologous stem cell transplantation (ASCT), reported Shahram Mori, MD, PhD, of the Florida Hospital Cancer Institute in Orlando, and his colleagues.
The findings suggest that P53 gene status in L-NN-MCL may have a significant impact on prognosis and treatment planning. There are currently no guidelines for risk stratifying L-NN-MCL patients.
“Although the recognition of L-NN-MCL is important to avoid overtreatment, there appears to be a subset of patients who either have a more aggressive form or disease that has transformed to a more aggressive form who present with symptomatic disease and/or cytopenias,” the investigators wrote in Clinical Lymphoma, Myeloma & Leukemia.
The investigators described two such cases in their report. Both patients had leukocytosis with various other blood cell derangements and splenomegaly without lymphadenopathy.
The first patient was a 53-year-old African American man with L-NN-MCL and a number of genetic aberrations, including loss of the P53 gene. After two cycles of rituximab with bendamustine proved ineffective, he was switched to rituxan with cyclophosphamide, vincristine, adriamycin, and dexamethasone with high-dose methotrexate and cytarabine. This regimen was also ineffective and his white blood cell count kept rising.
His story changed for the better when the patient was switched to ibrutinib 560 mg daily and rituximab 375 mg/m2 monthly. Within 2 months of starting therapy, his blood abnormalities normalized, and bone marrow biopsy at the end of treatment revealed complete remission without evidence of minimal residual disease. The patient remains in complete remission 18 months after ASCT.
The second patient was a 49-year-old Hispanic man with L-NN-MCL. He had missense mutations in TP53 and KMT2A (MLL), a frameshift mutation in BCOR, and a t(11;14) translocation. Ibrutinib/rituximab was started immediately. After 1 month, his blood levels began to normalize. After five cycles, bone marrow biopsy showed complete remission with no evidence of minimal residual disease. Like the first patient, the second patient remains in complete remission 18 months after ASCT.
“To our knowledge, these are the first two cases of L-NN-MCL with P53 gene mutations/alterations that were successfully treated with a combination of rituximab and ibrutinib,” the investigators wrote. “Our two cases confirm the previous studies by Chapman-Fredricks et al, who also noted P53 gene mutation or deletion is associated with the aggressive course.”
The researchers reported having no financial disclosures.
SOURCE: Mori S et al. Clin Lymphoma Myeloma Leuk. 2019 Feb;19(2):e93-7.