Midostaurin: a magic bullet that blocks mast cell expansion and activation.

Clinically relevant features in patients with systemic mastocytosis (SM) include the cosmetic burden of lesional skin, mediator-related symptoms, and organ damage resulting from mast cell (MC) infiltration in advanced forms of SM. Regardless of the SM variant, expansion of neoplastic MC in the skin and other organs is triggered by mutant forms of KIT, the most prevalent being D816V. Activation of MC with subsequent release of chemical mediators is often caused by IgE-dependent mechanisms in these patients. Midostaurin, also known as PKC412, blocks the kinase activity of wild-type KIT and KIT D816V, counteracts KIT-dependent growth of neoplastic MC, and inhibits IgE-dependent mediator secretion. Based on this activity-profile, the drug has been used for treatment of patients with advanced SM. Indeed, encouraging results have been obtained with the drug in a recent multi-center phase II trial in patients with advanced SM, with an overall response rate of 60% and a substantial decrease in the burden of neoplastic MC in various organs. Moreover, midostaurin improved the overall survival and relapse-free survival in patients with advanced SM compared with historical controls. In addition, midostaurin was found to improve mediator-related symptoms and quality of life, suggesting that the drug may also be useful in patients with indolent SM suffering from mediator-related symptoms resistant to conventional therapies or those with MC activation syndromes. Ongoing and future studies will determine the actual value of midostaurin-induced MC depletion and MC deactivation in these additional indications.

The impact of a male or female thrombotic family history on contraceptive counseling: a cohort study.

UNLABELLED: Essentials It is unknown if a male or female thrombotic family history influences risk in female relatives. We assessed thrombotic risk in female relatives of male and female patients with thrombosis. A hormonally related female thrombotic family history further increases risk in female relatives. This information could be important in counseling women on contraceptive options. Click to hear Prof. Rosendaal's perspective on venous thrombosis: etiology, pathogenesis, and prognosis SUMMARY: Background Women from thrombophilic families have increased risk of venous thromboembolism (VTE), which increases further during oral contraceptive (COC) use and pregnancy-postpartum. Whether this additional risk differs between relatives of male and female patients, or is different when that female patient had a hormonally related VTE (during COC use/pregnancy), is unknown. Methods One thousand five female relatives of consecutive patients with VTE from a family-based cohort were retrospectively followed for incident VTE from ages 15 to 50, first VTE, or study inclusion. Absolute and relative VTE risks adjusted for factors of patients (sex, age) and relatives (thrombophilia, COC use, pregnancy) were estimated in relatives of female and male patients and in relatives of female patients with and without hormonally related VTE. Results Absolute risk in relatives of female (0.32 [95% confidence interval [CI] 0.23-0.43]) vs. male patients (0.39 [95% CI 0.28-0.53]) was comparable. However, the heterogeneity analysis of risk estimates suggested that in relatives of female vs. male patients, the contribution of pregnancy-postpartum (hazard ratio [HR] 11.6 [95% CI 6.3-21.3] vs. HR6.6 [95% CI 2.8-15.2]) and, to a lesser extent, COC use (HR3.6 [95% CI 1.8-7.1] vs. HR2.7 [95% CI 1.5-5.0]) to the VTE risk differs. Absolute risk was significantly higher in relatives of female patients with hormonally related VTE (0.43 [95% CI 0.3-0.6]) vs. relatives of female patients without hormonally related VTE (0.13 [95% CI 0.05-0.27]), HR3.28 [95% CI 1.5-7.9]). The higher contribution of pregnancy-postpartum and COC use to the VTE risk was mainly observed in relatives of patients with hormonally related VTE. Conclusions These findings suggest that a family history from a female patient, especially when VTE was hormonally related, may further increase VTE risk in her female relatives. This information could be important in counseling women on contraceptive options.

KIT mutation analysis in mast cell neoplasms: recommendations of the European Competence Network on Mastocytosis.

Although acquired mutations in KIT are commonly detected in various categories of mastocytosis, the methodologies applied to detect and quantify the mutant type and allele burden in various cells and tissues are poorly defined. We here propose a consensus on methodologies used to detect KIT mutations in patients with mastocytosis at diagnosis and during follow-up with sufficient precision and sensitivity in daily practice. In addition, we provide recommendations for sampling and storage of diagnostic material as well as a robust diagnostic algorithm. Using highly sensitive assays, KIT D816V can be detected in peripheral blood leukocytes from most patients with systemic mastocytosis (SM) that is a major step forward in screening and SM diagnosis. In addition, the KIT D816V allele burden can be followed quantitatively during the natural course or during therapy. Our recommendations should greatly facilitate diagnostic and follow-up investigations in SM in daily practice as well as in clinical trials. In addition, the new tools and algorithms proposed should lead to a more effective screen, early diagnosis of SM and help to avoid unnecessary referrals.

Proposed diagnostic algorithm for patients with suspected mastocytosis: a proposal of the European Competence Network on Mastocytosis.

Mastocytosis is an emerging differential diagnosis in patients with more or less specific mediator-related symptoms. In some of these patients, typical skin lesions are found and the diagnosis of mastocytosis can be established. In other cases, however, skin lesions are absent, which represents a diagnostic challenge. In the light of this unmet need, we developed a diagnostic algorithm for patients with suspected mastocytosis. In adult patients with typical lesions of mastocytosis in the skin, a bone marrow (BM) biopsy should be considered, regardless of the basal serum tryptase concentration. In adults without skin lesions who suffer from mediator-related or other typical symptoms, the basal tryptase level is an important parameter. In those with a slightly increased tryptase level, additional investigations, including a sensitive KIT mutation analysis of blood leucocytes or measurement of urinary histamine metabolites, may be helpful. In adult patients in whom (i) KIT D816V is detected and/or (ii) the basal serum tryptase level is clearly increased (>25-30 ng/ml) and/or (iii) other clinical or laboratory features suggest the presence of 'occult' mastocytosis or another haematologic neoplasm, a BM investigation is recommended. In the absence of KIT D816V and other signs or symptoms of mastocytosis or another haematopoietic disease, no BM investigation is required, but the clinical course and tryptase levels are monitored in the follow-up. In paediatric patients, a BM investigation is usually not required, even if the tryptase level is increased. Although validation is required, it can be expected that the algorithm proposed herein will facilitate the management of patients with suspected mastocytosis and help avoid unnecessary referrals and investigations.

Refined diagnostic criteria and classification of mast cell leukemia (MCL) and myelomastocytic leukemia (MML): a consensus proposal.

Mast cell leukemia (MCL), the leukemic manifestation of systemic mastocytosis (SM), is characterized by leukemic expansion of immature mast cells (MCs) in the bone marrow (BM) and other internal organs; and a poor prognosis. In a subset of patients, circulating MCs are detectable. A major differential diagnosis to MCL is myelomastocytic leukemia (MML). Although criteria for both MCL and MML have been published, several questions remain concerning terminologies and subvariants. To discuss open issues, the EU/US-consensus group and the European Competence Network on Mastocytosis (ECNM) launched a series of meetings and workshops in 2011-2013. Resulting discussions and outcomes are provided in this article. The group recommends that MML be recognized as a distinct condition defined by mastocytic differentiation in advanced myeloid neoplasms without evidence of SM. The group also proposes that MCL be divided into acute MCL and chronic MCL, based on the presence or absence of C-Findings. In addition, a primary (de novo) form of MCL should be separated from secondary MCL that typically develops in the presence of a known antecedent MC neoplasm, usually aggressive SM (ASM) or MC sarcoma. For MCL, an imminent prephase is also proposed. This prephase represents ASM with rapid progression and 5%-19% MCs in BM smears, which is generally accepted to be of prognostic significance. We recommend that this condition be termed ASM in transformation to MCL (ASM-t). The refined classification of MCL fits within and extends the current WHO classification; and should improve prognostication and patient selection in practice as well as in clinical trials.

Central nervous system involvement in mantle cell lymphoma: clinical features, prognostic factors and outcomes from the European Mantle Cell Lymphoma Network.

BACKGROUND: Central nervous system (CNS) involvement in mantle cell lymphoma (MCL) is uncommon, and the manifestations and natural history are not well described. PATIENTS AND METHODS: We present the data on 57 patients with MCL who developed CNS involvement, from a database of 1396 consecutively treated patients at 14 institutions. RESULTS: The crude incidence of CNS involvement was 4.1%, with 0.9% having CNS involvement at diagnosis. Blastoid histology, B-symptoms, elevated lactate dehydrogenase, Eastern Cooperative Group performance status ≥2 and a high Mantle Cell Lymphoma International Prognostic Index score were enriched in the cohort with CNS involvement, and the presence of ≥1 of these features defined a high-risk subset (an actuarial risk of CNS involvement 15% at 5 years) in a single-institution subset. The median time to CNS relapse was 15.2 months, and the median survival from time of CNS diagnosis was 3.7 months. The white blood cell count at diagnosis <10.9 × 109/l, treatment of CNS involvement with high-dose anti-metabolites, consolidation with stem cell transplant and achievement of complete response were all associated with improved survival. CONCLUSIONS: In MCL, CNS involvement is uncommon, although some features may predict risk. Once manifest outlook is poor; however, some patients who receive intensive therapy survive longer than 12 months.

Incidence of hypersensitivity skin reactions in patients on full-dose low-molecular-weight heparins during pregnancy.

BACKGROUND: Low-molecular-weight heparins (LMWH) are the most commonly used anticoagulants for the treatment and prophylaxis of venous thromboembolism in pregnancy. Hypersensitivity skin reactions associated with the use of LMWH are frequently seen, but are probably underreported. OBJECTIVE: To evaluate the incidence of hypersensitivity skin reactions due to the use of LMWH in pregnancy, and the subsequent management of anticoagulation. PATIENTS/METHODS: From 1999 to 2009, we followed consecutive women who used therapeutic anticoagulation for venous indications. Women visited a combined obstetric/coagulation clinic and were seen by a thrombosis specialist every two months until six weeks postpartum. All women were started on nadroparin. RESULTS: We included 135 pregnancies in 88 women. Overall, in 52 of 135 pregnancies (39%), women switched at least once to another anticoagulant because of the development of hypersensitivity skin reactions. Switching to another preparation of LMWH was effective in 77% of the cases. In 23% of the cases skin reactions recurred and another switch had to be made. CONCLUSION: In almost half of the pregnancies, women had to switch at least once to another anticoagulant preparation due to the development of hypersensitivity skin reactions on LMWH. In most cases, skin reactions did not recur on the second preparation of LMWH used.

Treatment of older patients with mantle-cell lymphoma.

BACKGROUND: The long-term prognosis for older patients with mantle-cell lymphoma is poor. Chemoimmunotherapy results in low rates of complete remission, and most patients have a relapse. We investigated whether a fludarabine-containing induction regimen improved the complete-remission rate and whether maintenance therapy with rituximab prolonged remission. METHODS: We randomly assigned patients 60 years of age or older with mantle-cell lymphoma, stage II to IV, who were not eligible for high-dose therapy to six cycles of rituximab, fludarabine, and cyclophosphamide (R-FC) every 28 days or to eight cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) every 21 days. Patients who had a response underwent a second randomization to maintenance therapy with rituximab or interferon alfa, each given until progression. RESULTS: Of the 560 patients enrolled, 532 were included in the intention-to-treat analysis for response, and 485 in the primary analysis for response. The median age was 70 years. Although complete-remission rates were similar with R-FC and R-CHOP (40% and 34%, respectively; P=0.10), progressive disease was more frequent with R-FC (14%, vs. 5% with R-CHOP). Overall survival was significantly shorter with R-FC than with R-CHOP (4-year survival rate, 47% vs. 62%; P=0.005), and more patients in the R-FC group died during the first remission (10% vs. 4%). Hematologic toxic effects occurred more frequently in the R-FC group than in the R-CHOP group, but the frequency of grade 3 or 4 infections was balanced (17% and 14%, respectively). In 274 of the 316 patients who were randomly assigned to maintenance therapy, rituximab reduced the risk of progression or death by 45% (in remission after 4 years, 58%, vs. 29% with interferon alfa; hazard ratio for progression or death, 0.55; 95% confidence interval, 0.36 to 0.87; P=0.01). Among patients who had a response to R-CHOP, maintenance therapy with rituximab significantly improved overall survival (4-year survival rate, 87%, vs. 63% with interferon alfa; P=0.005). CONCLUSIONS: R-CHOP induction followed by maintenance therapy with rituximab is effective for older patients with mantle-cell lymphoma. (Funded by the European Commission and others; ClinicalTrials.gov number, NCT00209209.).

The circulating platelet count is not dictated by the liver, but may be determined in part by the bone marrow: analyses from human liver and stem cell transplantations.

BACKGROUND: The platelet count varies considerably between individuals, but within an individual the platelet count is remarkably stable over time. Mechanisms controlling the platelet count are not yet established. OBJECTIVE: In the present study, we tested the hypothesis that the liver is important in controlling the circulating platelet count, as the liver is the main producer of thrombopoietin. METHODS: We compared the platelet count prior to and after liver transplantation in >250 patients transplanted for familial amyloidotic polyneuropathy (FAP). In contrast to most patients undergoing liver transplantation, patients with FAP have normal liver function before transplantation. Furthermore, we compared platelet counts in 89 living liver donors with the platelet count in the recipients of these grafts. Finally we compared platelet counts in donor-recipient pairs of hematopoietic stem cells. RESULTS AND CONCLUSIONS: The platelet count prior to transplantation correlated with the platelet count at 3 or 12 months after transplantation in patients with FAP (r=0.48, P<0.0001 at 3 months, r=0.39, P<0.0001 at 12 months), whereas the platelet count in a living liver donor did not correlate with the platelet count in the recipient at 3 or 12 months after transplantation (r=0.16, P=0.26 at 3 months, r=0.11, P=0.30 at 12 months). The platelet count of related donors of hematopoietic stem cells correlated with the platelet count in the recipient after transplantation (r=0.25, P=0.011). CONCLUSIONS: These results suggest that the liver, in spite of being the prime producer of thrombopoietin, does not dictate the circulating platelet count, whereas the bone marrow does appear to play a role.

Insulin resistance and risk of venous thromboembolism: results of a population-based cohort study.

BACKGROUND: Obesity is an established risk factor for venous thromboembolism (VTE), but it is uncertain how this is mediated. Insulin resistance has a central role in the pathophysiology of the metabolic effects of obesity. OBJECTIVE: We aimed to investigate whether insulin resistance is a risk factor for VTE. METHODS: For this analysis we used the PREVEND prospective community-based observational cohort study. Insulin resistance was measured as HOMA-IR (homeostasis model assessment of insulin resistance) and fasting insulin. VTE was assessed using databases of the national registries of hospital discharge diagnoses, death certificates and the regional anticoagulation clinic. RESULTS: Out of 7393 subjects, 114 developed VTE during a median follow-up of 10.5 years. High HOMA-IR was associated with increased risk of VTE after adjustment for traditional cardiovascular risk factors, CRP and markers of endothelial dysfunction (hazard ratio [HR], 1.38; 95% confidence interval [95% CI], 1.09-1.75; P=0.007). When body mass index (BMI) was added to the model, BMI was a strong risk predictor for VTE (HR, 1.53; 95% CI, 1.24-1.88; P<0.001) whereas HOMA-IR no longer showed such an association (HR, 1.11; 95% CI, 0.85-1.43; P=0.45). Results were similar for fasting insulin. CONCLUSION: Our population-based cohort study shows an increased risk of VTE in subjects with increasing insulin resistance but not independently of BMI.

High prevalence of fractures and osteoporosis in patients with indolent systemic mastocytosis.

BACKGROUND: Indolent systemic mastocytosis (ISM) is a rare disease characterized by accumulation of abnormal mast cells in various tissues, including bone marrow. Symptoms are usually related to release of mast cell mediators. The aims are to establish the prevalence of osteoporotic fractures in ISM and to investigate the association with serum tryptase and the urinary histamine metabolites, methylhistamine (MH), and methylimidazole acetic acid. METHODS: The fracture prevalence in 157 patients (65 men; 92 women), mean age 54 ± 12 years, was assessed by vertebral morphometry and data from patient records, supplemented by a questionnaire. Bone mineral density (BMD) of lumbar spine and femoral neck was measured, and tryptase and histamine metabolites were analysed. RESULTS: We registered 235 lifetime fractures in 154 patients, including 140 osteoporotic (low-energy trauma) fractures, of which 62% were vertebral, 1% hip and 36% other nonvertebral fractures. Osteoporotic fractures and osteoporosis were found in 37% and 28% of the patients, respectively. In men, the prevalence of these osteoporotic manifestations (46% <50 years; 73% ≥50 years) was much higher compared with women (18% <50 years; 58% ≥50 years). Older age, male gender, and higher urinary MH were independently related to the osteoporotic manifestations. CONCLUSIONS: This first publication about prevalence of fractures and osteoporosis in patients with ISM shows that the risk of osteoporotic fractures is high, especially in men. Higher urinary MH levels are associated with a higher risk of osteoporotic manifestations. Routine measurements of BMD and vertebral morphometry are warranted in these patients for early detection of osteoporosis.

The impact of antiproteinuric therapy on the prothrombotic state in patients with overt proteinuria.

BACKGROUND: Overt proteinuria is a strong risk factor for thromboembolism, owing to changes in the levels of various coagulation proteins and urinary antithrombin loss. The described coagulation disturbances in these patients are based on outdated studies conducted primarily in the 1970s and 1980s. Whether these coagulation disturbances resolve with antiproteinuric therapy has yet to be studied. METHODS: A total of 32 patients with overt proteinuria (median, 3.7 g day(-1) ; interquartile range, 1.5-5.6) were enrolled in this intervention crossover trial designed to assess optimal antiproteinuric therapy with sodium restriction, losartan, and diuretics. Levels of various procoagulant and anticoagulant proteins, and parameters of two thrombin generation assays (calibrated automated thrombogram [CAT] and prothrombin fragment 1 + 2) were compared between the placebo period and the maximum antiproteinuric treatment period. As a secondary analysis, coagulation measurements of the placebo period in these patients were compared with those of 32 age-matched and sex-matched healthy controls. RESULTS: Median proteinuria was significantly lower during the maximum treatment period (median, 0.9 g day(-1) ; interquartile range, 0.6-1.4; P < 0.001) than during the placebo period. Similarly, levels of various liver-synthesized procoagulant and anticoagulant proteins, activated protein C resistance and prothrombin fragment 1 + 2 levels were significantly lower during the maximum treatment period than during the placebo period. However, von Willebrand factor and factor VIII levels were similar. On the basis of the higher levels of procoagulant proteins (fibrinogen, FV, FVIII, and von Willebrand factor) and both thrombin generation assays, patients were substantially more prothrombotic than healthy controls (P < 0.004). CONCLUSIONS: Antiproteinuric therapy ameliorates the prothrombotic state. Proteinuric patients are in a more prothrombotic state than healthy controls.

Intensified alemtuzumab-CHOP therapy for peripheral T-cell lymphoma.

BACKGROUND: The prognosis of T-cell lymphoma is poor. To explore the addition of the monoclonal antibody alemtuzumab, we studied the efficacy and tolerability of an intensified alemtuzumab-chemotherapy combination for aggressive T-cell lymphoma in a phase II study by Dutch-Belgian Hemato-Oncology Group (HOVON). PATIENTS AND METHODS: Patients (≤65 years) with newly diagnosed T-cell lymphoma received eight CHOP cycles (cyclophosphamide, doxorubicin, vincristine, prednisone) 2-weekly, each cycle with three doses of 30 mg alemtuzumab. Prophylaxis consisted of cotrimoxazole, fluconazole and valaciclovir. Cytomegalovirus (CMV) monitoring took place at least every fortnight. RESULTS: Twenty patients from 10 centers, median age 50 years, were included. Eighty-five percent received six or more cycles. The overall response was 90% [12 complete remissions (CRs), 1 CR unconfirmed, 5 partial remissions]. Median duration of follow-up of patients still alive was 29 months (range 19-41 months). Median overall survival (OS) and event-free survival (EFS) were 27 and 10 months, with 55%/27% OS/EFS at 2 years. Adverse events consisted of neutropenic fever (n = 8) and CMV reactivation (n = 7), with one CMV disease. Three patients developed secondary Epstein-Barr virus (EBV)-related lymphoma, all after end of treatment. CONCLUSIONS: Although intensified alemtuzumab-CHOP induces high responses, many patients relapse, and the scheme is associated with serious infection-related adverse events. EBV monitoring after end of treatment is required.

Prognostic value of comorbidity for auto-SCT eligibility and outcome in relapsed or refractory aggressive non-Hodgkin's lymphoma.

Salvage reinduction therapy followed by high-dose chemotherapy (HDCT) and auto-SCT is the treatment of choice for fit patients with refractory or relapsed aggressive non-Hodgkin's lymphoma (NHL). We assessed the prognostic value of comorbidity at the time of relapse to predict receipt of auto-SCT and outcome. We analyzed 156 consecutive NHL patients, referred to our center between 1999 and 2007 for salvage reinduction therapy, followed by HDCT and auto-SCT. Comorbidity according to the hematopoietic SCT comorbidity index was scored at relapse and directly before HDCT and auto-SCT. Primary end points were actual receipt of auto-SCT and survival. At relapse, comorbidity scores of 0, 1-2 and ≥3 were found among 64 (41%), 62 (40%) and 30 (19%) patients, respectively. Ultimately, 95 patients received auto-SCT. Higher comorbidity scores at relapse were associated with significantly less chance of receiving auto-SCT and with inferior OS, independently from secondary age-adjusted International Prognostic Index (sAAIPI) scores. For transplanted patients, OS rates at 5 years were 62, 30 and 17% for relapse comorbidity scores of 0, 1-2 and ≥3, respectively. In patients with relapsed NHL, comorbidity at relapse is associated with receipt of auto-SCT and subsequent survival independently from the sAAIPI.

Transfused stored platelets have the same haemostatic function as circulating native platelets.

BACKGROUND AND OBJECTIVES: As thrombelastography (TEG) measures haemostasis in whole blood, we used this instrument to study whether transfused platelets (PLTs) have the same haemostatic function compared to native circulating PLTs. Further, we studied the effect of storage time on the haemostatic potential of platelet concentrates (PCs). MATERIALS AND METHODS: During the decrease in PLT count after chemotherapy, TEG parameters were measured serially until the transfusion trigger was reached in 92 patients. TEG parameters for different ranges of native circulating PLTs could be assessed, which were compared to ranges obtained in the thrombocytopenic period in which the patient received PLT transfusions. Finally, we compared the haemostatic potential of fresh PCs (1-3 days) with PCs with longer storage time (4-5 days). RESULTS: No differences could be found in haemostatic potential between native PLTs and transfused stored PLTs (all P-values > or = 0.1). The transfusion of fresh PLTs demonstrated better haemostatic effects than longer stored PLTs, measured 1 h after transfusion. Both the time until a fixed level of clot firmness was reached (K-time) and the rate of clot growth (alpha angle) were superior for fresh PCs. CONCLUSION: TEG is able to monitor the haemostatic effects of PLT transfusion, with comparable haemostatic properties of native circulating and transfused stored-PLTs. Further, our data suggest that limited storage time is associated with a better haemostatic capacity. However, before TEG can be applied as a qualitative test in PLT transfusion, further research is needed with focus on clinical outcomes like bleeding episodes.

A prospective cohort study on the absolute risks of venous thromboembolism and predictive value of screening asymptomatic relatives of patients with hereditary deficiencies of protein S, protein C or antithrombin.

BACKGROUND: Absolute risks of venous thromboembolism (VTE) in protein S-, protein C-, or antithrombin-deficient subjects are mainly based on retrospective data. Screening asymptomatic relatives of these patients is disputed, though studies addressing this issue have yet to be conducted. METHODS: We prospectively followed 382 relatives of 84 probands. Participants were assessed for other thrombophilic defects and occurrence of exogenous risk factors (i.e. surgery/trauma/immobilization, malignancies, use of systemic estrogens, and pregnancy/puerperium). After screening, deficient subjects were advised to use thromboprophylaxis during exogenous risk factors; use of oral contraceptives was discouraged. RESULTS: Overall annual incidence of VTE was 1.53% (95% CI, 1.00-2.34) in deficient vs. 0.29% (0.13-0.64) in non-deficient relatives; adjusted hazard ratio, 7.0 (95% CI, 2.7-18.0). Annual incidence of unprovoked VTE was 0.95% in deficient vs. 0.05% in non-deficient subjects; age-adjusted hazard ratio, 22.3 (P = 0.003). In contrast, annual incidence of provoked VTE was 0.58% vs. 0.24%; age-adjusted hazard ratio, 2.8 (P = 0.08). Fifty-five (37%) deficient and 80 (34%) non-deficient subjects experienced 91 and 143 exogenous risk factors, respectively, during which six vs. five VTEs (6.6% vs 3.5% per risk-period) occurred, despite the higher compliance with recommended thromboprophylaxis use in deficient (51%) vs. non-deficient (22%) subjects. In deficient subjects all provoked VTEs occurred when thromboprophylaxis was not used. CONCLUSIONS: Protein S, protein C or antithrombin deficiencies confer high absolute risk of VTE. Screening and subsequent augmentation of thromboprophylaxis use may result in reduction of provoked VTE, whereas risk of unprovoked VTE could not be affected by screening.

A phase II study of enzastaurin, a protein kinase C beta inhibitor, in patients with relapsed or refractory mantle cell lymphoma.

BACKGROUND: Protein kinase C beta (PKCbeta), a pivotal enzyme in B-cell signaling and survival, is overexpressed in most cases of mantle cell lymphoma (MCL). Activation of PI3K/AKT pathway is involved in pathogenesis of MCL. Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through PKCbeta/PI3K/AKT pathways, induces apoptosis, reduces proliferation, and suppresses tumor-induced angiogenesis. PATIENTS AND METHODS: Patients with relapsed/refractory MCL, and no more than four regimens of prior therapy, received 500 mg enzastaurin, orally, once daily. RESULTS: Sixty patients, median age 66 years (range 45-85), Eastern Cooperative Oncology Group performance status of zero to two (48% had baseline International Prognostic Index of 3-5), were enrolled. Most patients had prior CHOP-like chemotherapy and/or rituximab (median = 2 regimens). No drug-related deaths occurred. There was one case each of grade 3 anemia, diarrhea, dyspnea, vomiting, hypotension, and syncope. Fatigue was the most common toxicity. Although no objective tumor responses occurred, 22 patients (37%, 95% CI 25% to 49%) were free from progression (FFP) for > or =3 cycles (one cycle = 28 days); 6 of 22 were FFP for >6 months. Two patients remain on treatment and FFP at >23 months. CONCLUSION: Freedom from progression for >6 months in six patients and a favorable toxicity profile with minimal hematological toxicity indicate that enzastaurin warrants evaluation as maintenance therapy and combination chemotherapy in MCL.