Bosutinib shows low cross intolerance, in chronic myeloid leukemia patients treated in fourth line. Results of the Spanish compassionate use program

The role of bosutinib as rescue treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) patients after failing three previous tyrosine kinase inhibitors (TKIs) is currently unknown. We report here the largest series (to our knowledge) of patients treated with bosutinib in fourth-line, after retrospectively reviewing 30 patients in chronic phase, and pretreated with imatinib, nilotinib, and dasatinib. With a median follow up of 11.1 months, the probability to either maintain or improve their CCyR response was 56.6% (17/30) and 11 patients (36.7%) achieved or maintained their baseline MMR. In patients not having baseline CCyR, the probabilities of obtaining CCyR, MMR, and MR4.5 were 13, 11, and 14%, respectively. The probabilities of obtaining MMR and deep molecular response MR4.5 in patients with baseline CCyR were 40.0% (6/15) and 20.0% (3/15). At 20 months, progression-free survival was 73%. Grade 3-4 hematological toxicities were more frequent in resistant than intolerant patients (45.4 vs. 0.0%). Nonhematological toxicities were also more frequent in resistant patients, being diarrhea the most conspicuous one. Bosutinib seems to be an appropriate treatment option for patients resistant or intolerant to three prior TKI's.

Myelofibrosis: an update on current pharmacotherapy and future directions

INTRODUCTION

Myelofibrosis (MF) is a myeloproliferative neoplasm characterized by symptoms mainly derived from anemia and splenomegaly and constitutional symptoms and associated with a median survival around 6 years. Allogeneic stem cell transplantation (allo-SCT) remains the only curative therapy of MF but is applicable to a minority of patients. Discovery of the JAK2 mutation has provided the basis for the introduction of a new class of drugs, the JAK inhibitors, in the treatment of MF.

AREAS COVERED

A literature review on the therapy of MF has been performed through a PubMed search, with special attention being paid to the available data on transplantation, the JAK inhibitors, and other new drugs.

EXPERT OPINION

Conventional therapy of MF is usually adjusted to the predominant clinical symptoms in each patient, and its impact on survival is limited. Reduced-intensity conditioning regimens have increased the number of patients eligible for allo-SCT, but this procedure is still associated with substantial morbidity and mortality. The JAK inhibitors, such as ruxolitinib, can achieve profound symptomatic relief of the splenomegaly and the constitutional symptoms. However, they often accentuate the anemia and do not reduce the JAK2 allele burden, therefore lacking the potential to modify the natural history of MF.

Retreatment with purine analogs in patients with chronic lymphocytic leukemia

We evaluated the efficacy and toxicity of retreatment with purine analogs (PA) in 62 patients with relapsed chronic lymphocytic leukemia. Median OS and PFS after retreatment were 60 and 26 months, respectively. By multivariate analysis, minimal residual disease status, ZAP-70 expression and age had independent predictive power in terms of OS. Toxicity was mainly neutropenia (21%) and infections (39%). Second malignancies were observed in 10 (16%) patients. Our results outline that retreatment with PA is remarkably effective in patients with relapsed CLL, but with a significant toxicity.

Molecular subsets of mantle cell lymphoma defined by the IGHV mutational status and SOX11 expression have distinct biologic and clinical features

Mantle cell lymphoma (MCL) is a heterogeneous disease with most patients following an aggressive clinical course, whereas others having an indolent behavior. We conducted an integrative and multidisciplinary analysis of 177 MCL to determine whether the immunogenetic features of the clonotypic B-cell receptors (BcR) may identify different subsets of tumors. Truly unmutated (100% identity) IGHV genes were found in 24% cases, 40% were minimally/borderline mutated (99.9%-97%), 19% significantly mutated (96.9%-95%), and 17% hypermutated (<95%). Tumors with high or low mutational load used different IGHV genes, and their gene expression profiles were also different for several gene pathways. A gene set enrichment analysis showed that MCL with high and low IGHV mutations were enriched in memory and naive B-cell signatures, respectively. Furthermore, the highly mutated tumors had less genomic complexity, were preferentially SOX11-negative, and showed more frequent nonnodal disease. The best cut-off of germline identity of IGHV genes to predict survival was 97%. Patients with high and low mutational load had significant different outcome with 5-year overall survival (OS) of 59% and 40%, respectively (P = 0.004). Nodal presentation and SOX11 expression also predicted for poor OS. In a multivariate analysis, IGHV gene status and SOX11 expression were independent risk factors. In conclusion, these observations suggest the idea that MCL with mutated IGHV, SOX11-negativity, and nonnodal presentation correspond to a subtype of the disease with more indolent behavior.