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Introduction: Acute myeloblastic leukemia (AML) is the most frequent type of acute leukemia in adults with an incidence of 4.2 cases per 100,000 inhabitants and poor 5-year survival. Patients with mutations in the FMS-like tyrosine kinase 3 ( FLT3) gene have poor survival and higher relapse rates compared with wild-type cases. Areas covered: Several FLT3 inhibitors have been proved in FLT3 mut AML patients, with differences in their pharmacokinetics, kinase inhibitory and adverse events profiles. First-generation multi-kinase inhibitors (midostaurin, sorafenib, lestaurtinib) target multiple proteins, whereassecond-generation inhibitors (crenolanib, quizartinib, gilteritinib) are more specific and potent inhibitors of FLT3, so they are associated with less off-target toxic effects. All of these drugs have primary and acquired mechanisms of resistance, and therefore their combinations with other drugs (checkpoint inhibitors, hypomethylating agents, standard chemotherapy) and its application in different clinical settings are under study. Expert opinion: The recent clinical development of various FLT3 inhibitors for the treatment of FLT3 mut AML is an effective therapeutic strategy. However, there are unique toxicities and drug-drug interactions that need to be resolved. It is necessary to understand the mechanisms of toxicity in order to recognize and manage them adequately.

Thrombosis and neoplasms are strictly linked, and the diagnosis of a malignancy is a relevant risk factor for venous thromboembolism (VTE). In particular, between gammopathies, the VTE risk is known to be increased in both monoclonal gammopathy of uncertain significance and in multiple myeloma, with a 3- and 9-fold increase respectively, when compared to the general population. The risk appears to be further increased in patients treated with immunomodulating drugs, such as thalidomide, especially when in combination with dexamethasone or conventional cytotoxic chemotherapies, and lenalidomide. In 2008 the International Myeloma Working Group put out thrombosis prophylaxis recommendations for myeloma patients treated with IMiDs. Current recommendations for thromboprophylaxis suggest the use of low-dose acetylsalicylic acid in patients with low risk for thrombosis and therapeutic dose anticoagulation with LMWH or warfarin for high-risk patients. However, these recommendations have been frequently not followed in the clinical practice, due to various reasons that involve the patients' will, the level of evidence of the recommendations and some selection biases in the studies that were taken as basis for writing down the indications. The new direct oral anticoagulants have been preliminarily evaluated for the prophylaxis of thrombotic events in IMiDs-treated myelomas, being promising, even if more expensive. Currently, the most reliable tool for a correct thrombotic risk stratification appears to be the complete clinical and anamnestic evaluation of the myeloma patients added to a strong physician awareness of the evidences that the literature contains until now.

Introduction: Over the last two decades, the outcomes of patients with multiple myeloma (MM), a malignant plasma cells dyscrasia, have dramatically improved. The development and the introduction of the immunomodulatory drugs (IMiDs) which include thalidomide, lenalidomide, and pomalidomide, have contributed significantly to these improvements., Evidence Acquisition: The IMiDs have been shown a multitude of mechanisms of action, including antiangiogenic, cytotoxic and immunomodulatory. The more recent discoveries that the IMiDs bind to cereblon and thus regulate the ubiquitination of key transcription factors including IKZF1 and IKZF3, have provided new insight about their activities., Evidence Synthesis: The IMIDs are widely used in the treatment of the different setting of MM patients and particularly lenalidomide represents the backbone in the therapy of newly diagnosed transplant eligible and transplant ineligible patients, in the maintenance setting post-transplant and in the relapsed/refractory setting, while pomalidomide is currently utilized in the relapsed/refractory setting., Conclusions: Here the mechanisms of action, the clinical efficacy and the management of side effects are reviewed as well as the new classes of cereblon E3 ligase modulator (CELMoD) and their promising clinical data are described.

While the outcome of patients with multiple myeloma has significantly improved over the last two decades, the disease remains incurable for the majority of patients. With the advent of novel agents, there has been a shift towards prolonged therapy as opposed to fixed-duration therapy, aimed at improving progression-free survival and overall survival. Evidence favoring continuous therapy has emerged over the last 2 decades and in the context of maintenance after proteasome inhibitor plus immunomodulatory drug induction followed by high dose melphalan and stem cell transplantation, this leads to >80% overall survival at 5 years. Maintenance therapy specifically has been demonstrated to correlate with increasing depth of disease response with a significant proportion of patients who remain minimal residual disease positive at the end of induction therapy achieving minimal residual disease negativity with maintenance therapy both in clinical trials and selected real world populations. As the survival improves, it is crucial to identify patients who are projected to have better survival and spare them toxicities arising from indefinite maintenance therapy. The role of minimal residual disease in this context is being investigated in numerous clinical trials and in the next few years the goal should be to use this in a rational way to achieve the ability to identify patients who would require continuation or escalation of therapy to improve their projected survival as well as to identify the group of patients in whom maintenance therapy could perhaps be time-limited without compromising their survival. Here we review the evidence for maintenance therapy from the key trials in the past years, present an overview of the current landscape and our perspective of maintenance therapy in the future.

Proteasome inhibitors (PIs) represent a recently developed drug class that inhibit the ubiquitin-proteasome system, thus interfering with the intracellular machinery who has the duty of misfolded proteins disposal. Myeloma plasma cells are structurally aimed at the production of large quantities of immunoglobulins. This explains their vulnerability to any perturbation of intracellular protein homeostasis. Bortezomib is the first-in-class PI and nowadays, in combination with other compounds, is the cornerstone of multiple myeloma (MM) treatment in several settings. Bortezomib has several attractive features for its inclusion in the induction phase of therapy: high efficacy, rapid cytoreduction, absence of nephrotoxicity, fast reduction of plasmacytomas, and fast pain control. However, the safety profile of bortezomib is characterized by a not negligible peripheral neuropathy. Newer PIs, such as carfilzomib and ixazomib, have been developed and each offers specific advantages. Carfilzomib is extremely efficient in proteasome inhibition. This results in high efficacy but suffers from a significant cardiotoxicity. Ixazomib is the first oral PI with a proteasome inhibition profile similar to bortezomib, with lower neurotoxicity. PIs mechanism of action is complementary with other drug classes, and this explains the synergism between PIs and other drugs, in particular steroids and immunomodulators. PIs are frequently used in doublets and triplets. Also, they can be associated with anti-CD38 monoclonal antibodies. This review summarizes the principal biological and clinical features of PIs in the MM treatment.

The isocitrate dehydrogenases enzymes, IDH1 and IDH2, catalyze the conversion of isocitrate to α-ketoglutarate (αKG) in the cell cytoplasm and mitochondria, respectively, and contribute to generating the dihydronicotinamide-adenine dinucleotide phosphate (NADPH) as reductive potential in different cellular processes. Mutations in IDH1 and IDH2 genes are found collectively in about 20-25% of acute myeloid leukemia (AML) patients. Mutant IDH enzymes have neomorphic activity and convert αKG to the oncometabolite R-2-hydroxyglutarate (R-2-HG) which accumulates at high levels in the cell and hampers the function of αKG-dependent enzymes, including epigenetic regulators, thus leading to altered gene expression and block of differentiation and contributing to leukemia development. Inhibition of the neomorphic mutants induces marked decrease in R-2-HG levels and restores myeloid differentiation. Enasidenib and ivosidenib are potent and selective inhibitors of mutant IDH2 and IDH1, respectively, act as differentiating agents and showed clinical activity in relapsed/refractory (R/R) AML harboring the specific mutation. As single agents, both drugs have been approved by the Food and Drug Administration (FDA) for the treatment of R/R AML. The relevance of IDH targeting within either single agent approach or, most importantly, combinatorial treatments in AML will be discussed.

Mutations in the FMS-like tyrosine kinase 3 (FLT3) gene arise in 25-30% of all acute myeloid leukemia (AML) patients. These mutations lead to constitutive activation of the protein product and are divided in two broad types: internal tandem duplication (ITD) of the juxtamembrane domain (25% of cases) and point mutations in the tyrosine kinase domain (TKD). Patients with FLT3 ITD mutations have a high relapse risk and inferior cure rates, whereas the role of FLT3 TKD mutations still remains to be clarified. Additionally, growing research indicates that FLT3 status evolves through a disease continuum (clonal evolution), where AML cases can acquire FLT3 mutations at relapse - not present in the moment of diagnosis. Several FLT3 inhibitors have been tested in patients with FLT3-mutated AML. These drugs exhibit different kinase inhibitory profiles, pharmacokinetics and adverse events. First-generation multi-kinase inhibitors (sorafenib, midostaurin, lestaurtinib) are characterized by a broad-spectrum of drug targets, whereas second-generation inhibitors (quizartinib, crenolanib, gilteritinib) show more potent and specific FLT3 inhibition, and are thereby accompanied by less toxic effects. Notwithstanding, all FLT3 inhibitors face primary and acquired mechanisms of resistance, and therefore the combinations with other drugs (standard chemotherapy, hypomethylating agents, checkpoint inhibitors) and its application in different clinical settings (upfront therapy, maintenance, relapsed or refractory disease) are under study in a myriad of clinical trials. This review focuses on the role of FLT3 mutations in AML, pharmacological features of FLT3 inhibitors, known mechanisms of drug resistance and accumulated evidence for the use of FLT3 inhibitors in different clinical settings.

The inhibition of the DNA damage response (DDR) pathway in the treatment of cancer has recently gained interest, and different DDR inhibitors have been developed. Among them, the most promising ones target the WEE1 kinase family, which has a crucial role in cell cycle regulation and DNA damage identification and repair in both nonmalignant and cancer cells. This review recapitulates and discusses the most recent findings on the biological function of WEE1/PKMYT1 during the cell cycle and in the DNA damage repair, with a focus on their dual role as tumor suppressors in nonmalignant cells and pseudo-oncogenes in cancer cells. We here report the available data on the molecular and functional alterations of WEE1/PKMYT1 kinases in both hematological and solid tumors. Moreover, we summarize the preclinical information on 36 chemo/radiotherapy agents, and in particular their effect on cell cycle checkpoints and on the cellular WEE1/PKMYT1-dependent response. Finally, this review outlines the most important pre-clinical and clinical data available on the efficacy of WEE1/PKMYT1 inhibitors in monotherapy and in combination with chemo/radiotherapy agents or with other selective inhibitors currently used or under evaluation for the treatment of cancer patients.

Despite novel agents, multiple myeloma is still an incurable disease, especially for elderly and frail patients, who are difficult to manage for concomitant comorbidities as the therapeutic options are limited and the response to chemotherapy is often short. We report our evaluations upon safety and efficacy of domestic subcutaneous bortezomib in elderly and frail patients candidate to bortezomib-melphalan-prednisone (VMP) regimen. We confirmed that overall incidence of adverse events, including peripheral neuropathy, was low, and in no case required admission to emergency service, contributing to reduce the rate of therapy discontinuation. These results confirm the effectiveness and safety of subcutaneous bortezomib, in a real-life-experience, and define a new possibility of safe auto-administration in a comfortable domestic setting. We suggest that domestic treatment can significantly improve the quality of life of the patients, avoiding unnecessary transfer to the hospital without reducing treatment efficacy.