The introduction of all-trans retinoic acid (ATRA) and, more recently, arsenic trioxide (ATO) into the therapy of acute promyelocytic leukemia (APL) has revolutionized the management and outcome of this disease. Several treatment strategies using these agents, usually in combination with chemotherapy, but also without or with minimal use of cytotoxic agents, have provided excellent therapeutic results. Cure of APL patients, however, is also dependent on peculiar aspects related to the management and supportive measures that are crucial to counteract life-threatening complications associated with the disease biology and molecularly targeted treatment. The European LeukemiaNet recently appointed an international panel of experts to develop evidence-and expert opinion-based guidelines on the diagnosis and management of APL. Together with providing current indications on genetic diagnosis, modern risk-adapted front-line therapy and salvage treatment, the review contains specific recommendations for the identification and management of most important complications such as the bleeding disorder, APL differentiation syndrome, QT prolongation and other ATRAand ATO-related toxicities, as well as for molecular assessment of response to treatment. Finally, the approach to special situations is also discussed, including management of APL in children, elderly patients, and pregnant women.

Phase 2 studies suggest that the monoclonal antibody rituximab may improve the prognosis of patients with follicular lymphoma (FL) when it is added to chemotherapy. In the current study, 428 patients with untreated, advanced-stage FL were randomly assigned for therapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) alone (n ‫؍‬ 205) or CHOP combined with rituximab (R-CHOP) (n ‫؍‬ 223). R-CHOP reduced the relative risk for treatment failure by 60% and significantly prolonged the time to treatment failure (P < .001). In addition, a significantly higher overall response rate (96% vs 90%; P ‫؍‬ .011) and a prolonged duration of remission (P ‫؍‬ .001) were achieved. In spite of a relatively short observation time, these beneficial effects even translated to superior overall survival (P ‫؍‬ .016), with 6 deaths in the R-CHOP group compared with 17 deaths in the CHOP group within the first 3 years. The predominant treatment-related adverse effect was myelosuppression. Severe granulocytopenia was more frequently observed after R-CHOP (63% vs 53%; P ‫؍‬ .01). However, severe infections were rare and of similar frequency after R-CHOP and CHOP (5% and 7%

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The analysis of rare chromosomal translocations in myeloproliferative disorders has highlighted the importance of aberrant tyrosine kinase signaling in the pathogenesis of these diseases. Here we have investigated samples from 679 patients and controls for the nonreceptor tyrosine kinase JAK2 V617F mutation. Of the 480 myeloproliferative disorder (MPD) samples, the proportion of positive cases per disease subtype was 30 (20%) of 152 for atypical or unclassified MPD, 2 of 134 (2%) for idiopathic hypereosinophilic syndrome, 58 of 72 (81%) for polycythemia vera, 24 of 59 (41%) essential thrombocythemia (ET), and 15 of 35 (43%) for idiopathic myelofibrosis. V617F was not identified in patients with systemic mastocytosis (n ‫؍‬ 28), chronic or acute myeloid leukemia (n ‫؍‬ 35), secondary erythrocytosis (n ‫؍‬ 4), or healthy controls (n ‫؍‬ 160). Homozygosity for V617F was seen in 43% of mutant samples and was closely correlated with chromosome 9p uniparental disomy. Homozygosity was significantly less common in ET compared with other MPD subtypes. In 53 cases analyzed, the median level of PRV1 expression was significantly higher in V617F-positive cases compared with cases without the mutation. We conclude that V617F is widespread in MPDs. IntroductionChronic myeloproliferative diseases (CMPDs) are clonal hematopoietic stem cell disorders characterized by proliferation of one or more myeloid cell lineages in the bone marrow and increased numbers of mature and immature cells in the peripheral blood. CMPDs include polycythemia vera (PV), essential thrombocythemia (ET), idiopathic myelofibrosis (IMF) and chronic myeloid leukemia (CML), plus rarer subtypes such as chronic neutrophilic leukemia (CNL), hypereosinophilic syndrome (HES), and chronic eosinophilic leukemia (CEL). These diseases overlap with myelodysplastic/myeloproliferative diseases (MDS/MPDs) such as atypical CML (aCML) and chronic myelomonocytic leukemia (CMML), in which proliferation is accompanied by dysplastic features or ineffective hematopoiesis in other lineages. 1 We refer here broadly to all these groups as myeloproliferative disorders (MPDs).Although there are strict diagnostic criteria for MPD subtypes, precise categorization remains a subject of debate 2 and furthermore, it can be difficult to differentiate some cases from reactive disorders. Only CML is characterized by a pathognomonic molecular marker, the BCR-ABL fusion, and the primary abnormalities driving excess proliferation in most other cases have been obscure. However, several lines of evidence have implicated aberrant tyrosine kinase signaling as the root cause of MPDs. Breakpoint cluster region-abelson (BCR-ABL) itself is a constitutively active tyrosine kinase that is believed to be the primary, and probably the only, driving force behind chronic-phase CML. 3 Other gene fusions have been identified in rare cases of aCML, CMML, and HES/CEL that involve the tyrosine kinases PDGFRA, PDGFRB, FGFR1, and JAK2. 4,5 In addition, the KIT receptor is activated by point mutation in the majority...

Since the comprehensive recommendations for the management of acute promyelocytic leukemia (APL) reported in 2009, several studies have provided important insights, particularly regarding the role of arsenic trioxide (ATO) in frontline therapy. Ten years later, a European LeukemiaNet expert panel has reviewed the recent advances in the management of APL in both frontline and relapse settings in order to develop updated evidence- and expert opinion–based recommendations on the management of this disease. Together with providing current indications on genetic diagnosis, modern risk-adapted frontline therapy, and salvage treatment, the review contains specific recommendations for the identification and management of the most important complications such as the bleeding disorder APL differentiation syndrome, QT prolongation, and other all-trans retinoic acid– and ATO-related toxicities, as well as recommendations for molecular assessment of the response to treatment. Finally, the approach to special situations is also discussed, including management of APL in children, elderly patients, and pregnant women. The most important challenges remaining in APL include early death, which still occurs before and during induction therapy, and optimizing treatment in patients with high-risk disease.

Pharmacokinetics of 8 doses of rituximab (375 mg/m 2 ) given in combination with 2-week cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone/ prednisolone (CHOP-14) was determined by ELISA in 20 elderly patients with diffuse large B-cell lymphoma (DLBCL) 10 minutes before and after each infusion and 1 week and 1, 2, 3, 6, and 9 months after the last infusion. Population pharmacokinetic modeling was performed with nonlinear mixed-effect modeling software (NONMEM VI). Concentration-time data were fitted into an open 2-compartment model and total clearance, central compartment volume, intercompartment clearance, and volume of distribution at steady-state (Vd ss ) were investigated. Total clearance was 9.43 mL/h and Vd ss was 9.61 l. Rituximab clearance was reduced (8.21 mL/h vs 12.68 mL/h; P ‫؍‬ .003) and elimination half-life was prolonged in women compared with men (t 1/2␤ ‫؍‬ 30.7 vs 24.7 days; P ‫؍‬ .003). Body weight also affected Vd ss (0.1 l increase of Vd ss per kilogram above median of 75 kg). A sexdependent effect and the higher weight of males contribute to their faster rituximab clearance, which might explain why elderly males benefit less from the addition of rituximab to CHOP than females. This trial was registered on www.clinicaltrials. gov as numbers NCT00052936, EU-20243

Under harmonized conditions, older and younger patients with AML show modest differences in their risk profiles and equally no dose response to intensified chemotherapy. Their observed fundamental difference in outcome across all subgroups remains unexplained. Further molecular investigation may elucidate the age effect in AML and identify new targets.

Key Points Evidence exists that ELN criteria for response in ET and PV issued in 2009 do not provide relevant measures of benefit for patients. Revised recommendations for assessing response are provided.