Preetesh Jain

Ibrutinib is a Bruton tyrosine kinase inhibitor approved for the treatment of patients with relapsed refractory chronic lymphocytic leukemia (RR-CLL). We describe the characteristics, causes of discontinuation, and outcomes in patients who discontinued treatment with ibrutinib. One hundred twenty-seven patients were enrolled in various clinical trials of ibrutinib, with or without rituximab, at our center. Thirty-three (26%) patients have discontinued ibrutinib to date. The majority of those patients had high-risk features: 94% with unmutated immunoglobulin heavy chain variable gene rearrangement, 58% with del(17p) by fluorescence in situ hybridization, and 54% with a complex karyotype. Causes of discontinuation were disease transformation (7), progressive CLL (7), stem cell transplantation (3), adverse events (11), serious adverse events/deaths (3), and miscellaneous reasons (2). Twenty five patients (76%) died after discontinuing ibrutinib; the median overall survival was 3.1 months after discontinuation. Most patients with RR-CLL who discontinued ibrutinib early were difficult to treat and had poor outcomes.

Unprecedented advances in our understanding of the pathobiology, prognostication, and therapeutic options in mantle cell lymphoma (MCL) have taken place in the last few years. Heterogeneity in the clinical course of MCL-indolent vs aggressive-is further delineated by a correlation with the mutational status of the variable region of immunoglobulin heavy chain, methylation status, and SOX-11 expression. Cyclin-D1 negative MCL, in situ MCL neoplasia, and impact of the karyotype on prognosis are distinguished. Apart from Ki-67% and morphology pattern (classic vs blastoid/pleomorphic), the proliferation gene signature has helped to further refine prognostication. Studies focusing on mutational dynamics and clonal evolution on Bruton's tyrosine kinase (BTK) inhibitors (ibrutinib, acalabrutinib) and/or Bcl2 antagonists (venetoclax) have further clarified the prognostic impact of somatic mutations in TP53, BIRC3, CDKN2A, MAP3K14, NOTCH2, NSD2, and SMARCA4 genes. In therapy, long-term follow-up on chemo-immunotherapy studies has demonstrated durable remissions in some patients; however, long-term toxicities, especially from second cancers, are a serious concern with chemotherapy. The therapeutic options in MCL are constantly evolving, with dramatic responses from nonchemotherapeutic agents (ibrutinib, acalabrutinib, and venetoclax). Chimeric antigen receptor therapy and combinations of nonchemotherapeutic agents are actively being studied and our focus is shifting toward making the treatment of MCL chemotherapy-free. Still, MCL remains incurable. The following aspects of MCL continue to pose a challenge: disease transformation, role of the cytokine-microenvironmental milieu, incorporation of positron emission tomography-computerized tomography imaging, minimal residual disease in the prognosis, circulating tumor DNA testing for clonal evolution, predicting resistance to BTK inhibitors, and optimal management of patients who progress on BTK/Bcl2 inhibitors. Next-generation clinical trials should incorporate nonchemotherapeutic agents and personalize the treatment based upon the genomic profile of individual patient. Recent advances in the field of MCL are reviewed.

BACKGROUND: Mutations in the tumor protein 53 (TP53) gene predict a poor prognosis in patients with acute myeloid leukemia (AML). METHODS: Peripheral blood or bone marrow samples from 293 patients with newly diagnosed AML were analyzed with targeted, amplicon-based, next-generation sequencing-based mutation analysis. RESULTS: TP53 mutations were identified in 53 patients (18%; 45 were missense mutations). In 13 of the 53 patients, the most common pattern of amino acid substitution was a substitution of arginine to histidine on different codons. The clinical characteristics, pattern of mutations, response to different therapies, and outcomes of patients with AML-TP53-mutated (n = 53) versus wild-type TP53 (n = 240) were compared. TP53 mutations were significantly more likely in patients who had a complex karyotype; abnormalities of chromosome 5, 7, and 17; and therapy-related AML. Patients who had TP53-mutated AML had significantly lower incidence of mutations in Fms-like tyrosine kinase 3 (FLT3), rat sarcoma (RAS), and nucleophosmin (NPM1) and higher incidence of coexisting MPL mutations compared with those who had wild type TP53. The distribution of TP53 mutations was equal for both age groups (ages <60 years vs ≥60 years). TP53-mutated AML was associated with a lower complete remission rate (41% vs 57%; P = .04), a significantly inferior complete remission duration (at 2 years: 30% vs 55%; P = .001), and overall survival (at 2 years: 9% vs 24%; P ≤ .0001) irrespective of age or the type of treatment received (high-intensity vs low-intensity chemotherapy). CONCLUSIONS: The type of treatment received did not improve outcomes in younger or older patients with TP53-mutated AML. These data suggest that novel therapies are needed to improve the outcome of patients with AML who have TP53 mutations. Cancer 2016;122:3484-3491. © 2016 American Cancer Society.