Myeloproliferative neoplasms and inflammation: whether to target the malignant clone or the inflammatory process or both

The Philadelphia-negative myeloproliferative neoplasms (MPNs) are clonal disorders involving hematopoietic stem and progenitor cells and are associated with myeloproliferation, splenomegaly and constitutional symptoms. Similar signs and symptoms can also be found in patients with chronic inflammatory diseases, and inflammatory processes have been found to play an important role in the pathogenesis and progression of MPNs. Signal transduction pathways involving JAK1, JAK2, STAT3 and STAT5 are causally involved in driving both the malignant cells and the inflammatory process. Moreover, anti-inflammatory and immune-modulating drugs have been used successfully in the treatment of MPNs. However, to date, many unresoved issues remain. These include the role of somatic mutations that are present in addition to JAK2V617F, CALR and MPL W515 mutations, the interdependency of malignant and nonmalignant cells and the means to eradicate MPN-initiating and -maintaining cells. It is imperative for successful therapeutic approaches to define whether the malignant clone or the inflammatory cells or both should be targeted. The present review will cover three aspects of the role of inflammation in MPNs: inflammatory states as important differential diagnoses in cases of suspected MPN (that is, in the absence of a clonal marker), the role of inflammation in MPN pathogenesis and progression and the use of anti-inflammatory drugs for MPNs. The findings emphasize the need to separate the inflammatory processes from the malignancy in order to improve our understanding of the pathogenesis, diagnosis and treatment of patients with Philadelphia-negative MPNs.

Differential clinical effects of different mutation subtypes in CALR-mutant myeloproliferative neoplasms

A quarter of patients with essential thrombocythemia or primary myelofibrosis carry a driver mutation of CALR, the calreticulin gene. A 52-bp deletion (type 1) and a 5-bp insertion (type 2 mutation) are the most frequent variants. These indels might differentially impair the calcium binding activity of mutant calreticulin. We studied the relationship between mutation subtype and biological/clinical features of the disease. Thirty-two different types of CALR variants were identified in 311 patients. Based on their predicted effect on calreticulin C-terminal, mutations were classified as: (i) type 1-like (65%); (ii) type 2-like (32%); and (iii) other types (3%). Corresponding CALR mutants had significantly different estimated isoelectric points. Patients with type 1 mutation, but not those with type 2, showed abnormal cytosolic calcium signals in cultured megakaryocytes. Type 1-like mutations were mainly associated with a myelofibrosis phenotype and a significantly higher risk of myelofibrotic transformation in essential thrombocythemia. Type 2-like CALR mutations were preferentially associated with an essential thrombocythemia phenotype, low risk of thrombosis despite very-high platelet counts and indolent clinical course. Thus, mutation subtype contributes to determining clinical phenotype and outcomes in CALR-mutant myeloproliferative neoplasms. CALR variants that markedly impair the calcium binding activity of mutant calreticulin are mainly associated with a myelofibrosis phenotype.

Mutations and prognosis in primary myelofibrosis

Patient outcome in primary myelofibrosis (PMF) is significantly influenced by karyotype. We studied 879 PMF patients to determine the individual and combinatorial prognostic relevance of somatic mutations. Analysis was performed in 483 European patients and the seminal observations were validated in 396 Mayo Clinic patients. Samples from the European cohort, collected at time of diagnosis, were analyzed for mutations in ASXL1, SRSF2, EZH2, TET2, DNMT3A, CBL, IDH1, IDH2, MPL and JAK2. Of these, ASXL1, SRSF2 and EZH2 mutations inter-independently predicted shortened survival. However, only ASXL1 mutations (HR: 2.02; P<0.001) remained significant in the context of the International Prognostic Scoring System (IPSS). These observations were validated in the Mayo Clinic cohort where mutation and survival analyses were performed from time of referral. ASXL1, SRSF2 and EZH2 mutations were independently associated with poor survival, but only ASXL1 mutations held their prognostic relevance (HR: 1.4; P=0.04) independent of the Dynamic IPSS (DIPSS)-plus model, which incorporates cytogenetic risk. In the European cohort, leukemia-free survival was negatively affected by IDH1/2, SRSF2 and ASXL1 mutations and in the Mayo cohort by IDH1 and SRSF2 mutations. Mutational profiling for ASXL1, EZH2, SRSF2 and IDH identifies PMF patients who are at risk for premature death or leukemic transformation.

Results of a randomized study of the JAK inhibitor ruxolitinib (INC424) versus best available therapy (BAT) in primary myelofibrosis (PMF), post-polycythemia vera-myelofibrosis (PPV-MF) or post-essential thrombocythemia-myelofibrosis (PET-MF)

LBA6501

Background: MF, a myeloproliferative neoplasm characterized by dysregulation of the JAK pathway, is associated with splenomegaly, constitutional symptoms and reduced lifespan. Ruxolitinib is a potent and selective JAK1 and JAK2 inhibitor. Methods: COMFORT-II, a randomized (2:1) phase III study, compared the efficacy and safety of ruxolitinib PO BID with BAT (other agents or no therapy) in adults with intermediate-2 or high-risk (Cervantes et al, Blood 2009) PMF, PPV-MF or PET-MF and palpable splenomegaly. The primary endpoint was the proportion of patients (pts), stratified by baseline risk category, achieving ≥ 35% reduction in spleen volume at week (wk) 48 determined by MRI or CT. The key secondary endpoint was the proportion achieving ≥ 35% reduction in spleen volume at wk 24. Results: 219 pts were randomized: 146 to ruxolitinib and 73 to BAT. Both arms included 49% high- and 51% intermediate-2 risk pts. The wk 48 response rate was 28.5% vs 0% (ruxolitinib vs BAT, P < .0001). The wk 24 response rate was 31.9% vs 0% (ruxolitinib vs BAT, P < .0001). Median duration of response to ruxolitinib was 48 wks. The most common (> 20%) adverse events (AEs) of any grade were (ruxolitinib vs BAT) thrombocytopenia (44.5% vs 9.6%), anemia (40.4% vs 12.3%), diarrhea (24.0% vs 11.0%), and peripheral edema (21.9% vs 26.0%). Grade 3-4 AEs occurring in ≥ 5% of pts in the ruxolitinib arm were: anemia (11%) and thrombocytopenia (7.5%). The most frequent grade 3-4 AEs in the BAT arm were anemia, thrombocytopenia, pneumonia and dyspnea (each 4.1%). Seven deaths occurred on treatment or within 28 days after end of treatment: 4 (2.7%) ruxolitinib and 3 (4.1%) BAT. Disposition of discontinuations were (ruxolitinib vs BAT) 8.2% vs 5.5% due to AEs and 1.4% vs 12.3% due to withdrawn consent. Conclusions: The COMFORT-II study demonstrates that ruxolitinib provides marked and sustained clinical benefit in spleen size and an acceptable safety profile relative to BAT, extends the positive results of COMFORT-I which compared ruxolitinib with placebo, and may result in a new standard of care for a large number of patients with MF.

What are RBC-transfusion-dependence and -independence?

The term RBC-transfusion-dependence is widely-used by hematologists to describe a condition of severe anemia typically arising when erythropoiesis is reduced such that a person continuously requires ≥1 RBC-transfusions over a specified interval. Defining a person as RBC-transfusion-dependent has important implications in diverse hematological disorders especially because it strongly-correlated with decreased survival. Conversely, becoming RBC-transfusion-independent or receiving fewer RBC-transfusions over a specified interval is defined as improvement or response in many disease- and/or therapy-setting. Whether this correlates with improved survival is controversial. We used a structured expert-panel consensus panel process to define RBC-transfusion-dependence and -independence or improvement. We suggest these definitions may prove useful to persons studying or treating these diseases.

Induction and maintenance alpha-interferon therapy in myelofibrosis with myeloid metaplasia

In 12 patients having myelofibrosis with myeloid metaplasia (MMM), recombinant- alpha interferon (r-alpha INF) was given for 16 weeks at an initial dose of 3 x 10(6) U/day as a cytoreductive agent. At the end of the 16th wk, Hb showed minor changes; WBC were reduced from 43 x 10(9)/l, range 6.4-69.4, to 16 x 10(9)/l, range 5-39 (p = 0.05); platelets decreased from 845 x 10(9)/l, range 215-1748, to 370 x 10(9)/l, range 96-730 (p = 0.005). 2 cases responded at the starting dose, while the effective dose was 5 x 10(6) U/d in the others. Minor changes in spleen size were noted, while no significant changes in bone marrow fibrosis occurred. After induction therapy, 3 patients were allocated to maintenance therapy (from 10 up to 34 months). To maintain platelet count lower than 500 x 10(9)/l, the required r-alpha-INF dose was constantly 10 MU/wk, while the same result was not achieved in 1 case with hydroxyurea, 1 g/die. The association with hydroxyurea, 500 mg/die, allowed reduction of the r-alpha INF dose to 6 MU/die in 1 other case.

A unified definition of clinical resistance/intolerance to hydroxyurea in essential thrombocythemia: results of a consensus process by an international working group

A widely accepted definition of resistance or intolerance to hydroxyurea (HU) in patients with essential thrombocythemia (ET) is lacking. An international working group (WG) was convened to develop a consensus formulation of clinically significant criteria for defining resistance/intolerance to HU in ET. To this aim, an analytic hierarchy process (AHP), a multiple-attribute decision-making technique, was used. The steps consisted of selecting the candidate criteria for defining resistance/intolerance; identifying the motivations that could influence the preference of the WG for any individual criterion; comparing the candidate criteria in a pair-wise manner; and grading them according their ability to fulfill the motivations. Every step in the model was derived by questionnaires or group discussion. The WG proposed that the definition of resistance/intolerance should require the fulfillment of at least one of the following criteria: platelet count greater than 600,000/micro l after 3 months of at least 2 g/day of HU (2.5 g/day in patients with a body weight over 80 kg); platelet count greater than 400,000/micro l and WBC less than 2500/micro l or Hb less than 10 g/dl at any dose of HU; presence of leg ulcers or other unacceptable muco-cutaneous manifestations at any dose of HU; HU-related fever.

Strategies for dissemination and implementation of guidelines

Interventions designed to effectively implement and disseminate clinical practice guidelines (CPG) fall into different categories. A systematic review of the effectiveness and costs of different guideline development, dissemination and implementation strategies was recently undertaken by the Health Technology Assessment (HTA) Programme in UK. Overall, the majority of comparisons reporting dichotomous process data observed improvement in care. However, there was considerable variation in the observed effects both within and across interventions. Evaluation studies provided evidence that adherence of physicians to CPG is a strong predictor of the stroke outcome. Cochrane Collaboration performed a systematic review including studies published up to 2004 that compared integrated clinical pathways (ICP) for stroke care with standard medical care. They found no significant difference between ICP and control groups in terms of death or discharge destination. Patients managed with a care pathway were more dependent at discharge, less likely to suffer a urinary tract infection, less likely to be readmitted and more likely to have neuroimaging. A positive effect was reported from a validation study of a multifaceted strategy for stroke care ICP implementation in Italy.

Diagnostic and clinical relevance of the number of circulating CD34(+) cells in myelofibrosis with myeloid metaplasia

The absolute content of CD34(+) cells in the peripheral blood of 84 patients with myelofibrosis with myeloid metaplasia (MMM) and 23 patients with other Philadelphia-negative (Ph(-)) chronic myeloproliferative disorders (CMDs) was investigated. In MMM, the median absolute number of circulating CD34(+) cells was consistently high (91.6 x 10(6)/L; range, 0-2460 x 10(6)/L). Receiver operating characteristic curve analysis showed that 15 x 10(6)/L as a decision criterion for CD34(+) cells produced an almost complete discrimination between MMM patients out of therapy and other Ph(-) CMDs (positive predictive value, 98.4%; negative predictive value, 85.0%). MMM patients with higher numbers of CD34(+) cells had a significantly longer disease duration (P =.019) and higher spleen volume index (P =.014), liver volume (P =.000), percentage of circulating immature myeloid cells (P =.020), and percentage of myeloid blasts (P =.000). When CD34(+) cells were correlated with the use of Dupriez risk stratification, CD34(+) cells increased significantly from low-risk (median, 68.1 x 10(6)/L) to intermediate-risk (median, 112.8 x 10(6)/L) and high-risk patients (median 666.1 x 10(6)/L) (F = 4.95; P =.009). When CD34(+) cells were correlated with a severity score on the basis of both myeloproliferative and myelodepletive characteristics of the disease, only the myeloproliferation index was significantly associated with CD34(+) cell level (F = 5.7; P =.000). Overall survival and interval to blast transformation from the time of CD34(+) cell analysis were significantly shorter in patients with more than 300 x 10(6)/L CD34(+) cells (P =.005 and.0005, respectively). In conclusion, the absolute number of CD34(+) circulating cells allows MMM to be distinguished from other Ph(-) CMDs; it is strongly associated with the extent of myeloproliferation and predicts evolution toward blast transformation.

Low-molecular-weight heparin versus warfarin for secondary prophylaxis of venous thromboembolism: a cost-effectiveness analysis

PURPOSE

To compare the cost effectiveness of low-molecular-weight heparin with that of oral anticoagulants in preventing recurrences after an episode of venous thromboembolism.

METHODS

A decision tree was used to assess the cost and the expected quality-adjusted years of life (QALY) after treatment with either low-molecular-weight heparin or warfarin, based on pooled data from six published trials. Preferences were elicited with a modified time trade-off method in a sample of patients attending an anticoagulation clinic.

RESULTS

Compared with warfarin, low-molecular-weight heparin significantly decreased the rate of minor bleeding (odds ratio [OR] = 0.24; 95% confidence interval [CI]: 0.14 to 0.43) but not recurrent deep vein thromboses (OR = 0.77; 95% CI: 0.43 to 1.35). Patients' preference for warfarin (0.988, on a 0 to 1 scale) was lower than that for low-molecular-weight heparin (0.992), but the difference was not statistically significant. A Monte Carlo analysis estimated that low-molecular-weight heparin saved an average of 13 quality-adjusted days compared with warfarin, at a cost of $6,583 per QALY (95% CI: $5,525 to $7,625) based on costs in Italy and $28,231 per QALY (95% CI: $20,872 to $36,773) based on costs in the United States. When we included rebound recurrences after interruption of therapy, which were more common with low-molecular-weight heparin, treatment with low-molecular-weight heparin cost $53,166 per QALY in Italy and $177,166 per QALY in the United States.

CONCLUSIONS

Low-molecular-weight heparin might be a cost-effective drug for secondary prophylaxis of venous thromboembolism, especially in patients at high risk of recurrence and where the drug's cost is lower. The apparent increase in recurrence after interruption of therapy needs to be investigated more thoroughly before low-molecular-weight heparin can be recommended routinely.

Cost-effectiveness of screening and extended anticoagulation for carriers of both factor V Leiden and prothrombin G20210A

Carriers of a double thrombophilic mutation (factor V Leiden and prothrombin G20210A) are at high risk of a recurrent venous thromboembolism (VTE), and may benefit from a longer course of secondary prophylaxis. We examined the costs and health benefits of screening for both the mutations, provided that double heterozygotes undergo 2 years of anticoagulation as compared to the standard 6 months. We thus pooled the available evidence and calculated that the OR for recurrence in double heterozygotes was 5.9 (95% CI 2.65-13.20). A Markov model tracked patients' health lifelong, and calculated that prolonged prophylaxis saved 26 quality-adjusted days of life and $410 per double heterozygote treated. Screening all the patients with venous thromboembolism thus provided one additional day of life at the cost of 13624 $/QALY (95% CI 12 965-22 889). Screening was not cost-effective in those cohorts with a low prevalence of the mutations, a high bleeding risk or in those where prophylaxis prevented <65% of recurrences. Screening for factor V Leiden and prothrombin G20210A, with prolonged prophylaxis of double carriers, is cost-effective in most patients with VTE.

Safety and efficacy of thalidomide in patients with myelofibrosis with myeloid metaplasia

We administered the anti-angiogenic drug thalidomide to 21 patients (12 men) with myelofibrosis with myeloid metaplasia (MMM), who were not responsive to standard treatment. Patients received thalidomide at an escalating dose from 100 to 400 mg/d. Administration of the drug was discontinued before the planned 6 months of treatment in 19 patients (90.5%), mainly because of somnolence and/or fatigue, neurological symptoms or neutropenia. Of the 13 evaluable patients (who received more than 30 d of therapy), anaemia improved in three out of seven (43%) who were treated because of anaemia; thrombocytopenia improved in two out of three (66.6%) who were treated because of thrombocytopenia; splenomegaly was reduced in four (30.8%). Undesired increases in white blood cell and platelet counts were observed in three (23.1%) and five (38.5%) patients respectively. A severity score, indexed on haematological and clinical parameters, improved in two patients (15.4%), but worsened in five (38.5%). In conclusion, standard-dose thalidomide in MMM patients is burdened with a high rate of side-effects, which prevent prolonged treatment. Because the drug is effective in improving anaemia and thrombocytopenia and in reducing splenomegaly, low-dose therapy warrants evaluation. The unexpected observation of leucocytosis and thrombocytosis suggests biological studies and better criteria for selection of patients for treatment.

Myelofibrosis with myeloid metaplasia in adult individuals 30 years old or younger: presenting features, evolution and survival

Myelofibrosis with myeloid metaplasia (MMM) usually affects older people and is associated with a median survival of 3.5-5 yr. Survival of MMM patients 55 yr old or younger is longer, but there is no information on the youngest subset. The presenting features, evolution and survival were analyzed in 9 patients with MMM aged 30 yr or less, representing 2.8% of two series including 323 cases. Age ranged from 17 to 30 yr; 3 patients were males and 6 females. Five patients were asymptomatic and none had constitutional symptoms. Anemia was observed in 4 patients, being severe in only one. The WBC count was normal in 7 patients and 2 had mild leukocytosis; moderate thrombocytosis was observed in 7 patients. No patient showed blood blast cells or bone marrow cytogenetic abnormalities. With a median follow-up of 6.8 (range 0.8-28) yr, 2 patients died 10.7 and 9.9 yr from diagnosis, one from complications of bone marrow transplantation performed after progression of the disease and the other from gastrointestinal bleeding secondary to portal hypertension. Among remaining patients, one developed Budd-Chiari syndrome, another was lost to follow-up at 3 yr, and 5 remain asymptomatic and currently without treatment (one had been splenectomized at diagnosis). These results indicate that in most young adults with MMM the disease presents without adverse prognostic factors and may remain stable for years, which may be of interest when considering the treatment of such patients.

Deciding when to intervene: a Markov decision process approach

The aim of this paper is to point out the difference between static and dynamic approaches to choosing the optimal time for intervention. The paper demonstrates that classical approaches, such as decision trees and influence diagrams, hardly cope with dynamic problems: they cannot simulate all the real-world strategies and consequently can only calculate suboptimal solutions. A dynamic formalism based on Markov decision processes (MPPs) is then proposed and applied to a medical problem: the prophylactic surgery in mild hereditary spherocytosis. The paper compares the proposed approach with a static approach on the same medical problem. The policy provided by the dynamic approach achieved significant gain over the static policy by delaying the intervention time in some categories of patients. The calculations are carried out with DT-Planner, a graphical decision aid specifically built for dealing with dynamic decision processes.

Extended anticoagulation for prevention of recurrent venous thromboembolism in carriers of factor V Leiden--cost-effectiveness analysis

There is much debate over the appropriateness of prescribing prolonged anticoagulation to heterozygous carriers of factor V Leiden suffering a first episode of deep vein thrombosis (DVT). We, thus used meta-analysis to estimate from six eligible studies the summary odds-ratio of recurrent DVT in carriers of factor V Leiden versus non-carriers: 1.36 (CI, 1.05-1.78). After that, we used a decision model to compare lifelong costs and benefits of 6 months standard anticoagulation with those of screening for carriers of factor V Leiden and extending for 2 years their anticoagulation. Screening was a cost-effective strategy, since it provided 2 additional quality-adjusted days of life per patient at the cost of $12,833 per quality-adjusted year of life saved, as compared to standard management. However, screening was not cost-effective in patients who were predicted to incur fatal bleeding at a rate higher than 0.34% per year or recurrent DVT at a rate lower than 9% in the first 2 years. The screening policy was cost-saving if restricted to patients with idiopathic DVT and compliant to warfarin therapy.

Preoperative predictors of the need for allogeneic blood transfusion in lung cancer surgery

BACKGROUND

The use of blood-saving techniques in elective surgery can produce a favorable cost-benefit ratio only when there is a reasonable likelihood that transfusion will be required. To apply a targeted blood-sparing technique in lung cancer surgery, the patient's preoperative characteristics that predict the use of allogeneic blood transfusion (ABT) in this practice were investigated.

STUDY DESIGN AND METHODS

One hundred seventy-three consecutive patients who underwent primary lung cancer surgery were included in this retrospective study. Clinical and epidemiologic variables, lung tumor extension (TNM staging), and surgery type were analyzed by logistic regression to discover the preoperative predictors of ABT.

RESULTS

Thirty patients, 17.3 percent of all who underwent surgery and 19.9 percent of those who underwent resolvent surgery, received ABT. Excluding a patient who needed 18 units of RBCs, the number of ABT units required by transfused patients was 1. 93 +/- 0.88 (mean +/- SD). Extensive surgery, patient's age (< or =64 years), and elevated erythrocyte sedimentation rate (>45 mm/hour) were the preoperative variables that influenced the need for ABT. The definitive predictive model was able to recognize 82.3 percent of patients who received ABT and 95.6 percent of those who did not.

CONCLUSION

A predictive model can preoperatively identify patients at risk for needing ABT in lung cancer surgery. The model could be utilized to tailor blood-sparing intervention programs.

Cost-effectiveness of epoetin and autologous blood donationin reducing allogeneic blood transfusions incoronary artery bypass graft surgery

BACKGROUND

Coronary artery bypass graft (CABG) surgery accounts for a substantial portion of all allogeneic units of blood transfused. Drugs and autologous blood donation (ABD) are alternative or adjunctive methods for reducing complications and costs induced by allogeneic blood transfusions. Recombinant human erythropoietin (epoetin) has the potential to decrease perioperative need for allogeneic blood during CABG, but its high cost calls for a careful economic evaluation before it can be recommended for widespread use.

STUDY DESIGN AND METHODS

A decision tree was used to compare a hypothetical strategy of no epoetin with one in which epoetin was utilized to control blood transfusion needs in CABG; each strategy was tested with and without ABD. The impact of these strategies on both the quality-adjusted life years (QALYs) and costs ($US) was calculated.

RESULTS

Using epoetin alone and with ABD, respectively, avoided the transfusion of 0.61 and 1.35 units of allogeneic blood per patient and saved 0.000086 and 0.000146 QALYs per patient. This made cost-effectiveness (CE) higher than $7 million and $5 million for each QALY saved, respectively. ABD alone cost more than $1 million per QALY saved. If the risk of bacterial infections following allogeneic transfusions was included in the model, epoetin alone cost $6288 per QALY saved, while ABD, both alone and with epoetin, saved money.

CONCLUSION

On the basis of the existing evidence, neither of the blood-saving strategies modeled was a cost-effective means of avoiding the deleterious health effects of perioperative blood transfusions in CABG. However, if allogeneic blood-related infections were to be considered, both ABD and epoetin would be acceptable interventions.

Jugular vein thrombosis: a rare presentation of atypical chronic myeloproliferative disorder in a young woman

Venous thromboembolism is common in subjects with chronic myeloproliferative disorders and is a recognized presenting feature of occult myeloproliferation. We report the case of a young woman who presented with acute thrombosis in the right jugular vein and pulmonary embolism. Splenomegaly and myeloid proliferation with bone marrow fibrosis, in the absence of the criteria for typical myeloproliferative disorders, allowed a diagnosis of an atypical form of chronic myeloproliferative disorder. This form carries a high risk of thrombosis and venous thromboembolism can be the presenting feature, though the course is often indolent. Acute thrombosis in the right jugular vein has not been so far described in these subjects. The outcome of young people with myelofibrosis is unpredictable, but a normal level of hemoglobin and the absence of blast cells and constitutional symptoms at presentation identifies subjects with a low probability of rapid disease progression.

Myelofibrosis with myeloid metaplasia: diagnostic definition and prognostic classification for clinical studies and treatment guidelines

PURPOSE

Myelofibrosis with myeloid metaplasia (MMM) is a chronic myeloproliferative disorder characterized by bone marrow fibrosis and extramedullary hematopoiesis. Recent studies provide definite diagnostic criteria and prognostic classifications of the disease, and allogeneic stem-cell transplantation (SCT) now offers a chance of curing the disease. In order to put diagnostic criteria and prognostic classifications of the disease into the perspective of developing guidelines for treatment strategies, all studies published in the English literature over the last 30 years were reviewed.

MATERIALS AND METHODS

Studies were identified through a MEDLINE search (1966 to present) and from the bibliographies of relevant articles.

RESULTS

The Italian Consensus Conference on diagnostic criteria is a structured enterprise aimed at formulating a definition of MMM that will be used for enrolling patients onto clinical studies. It relies on the obligatory presence of myelofibrosis and on the exclusion of the BCR-ABL rearrangement or Philadelphia chromosome, in association with combinations of traditional features. Prognostic scores allow us to identify classes of patients on the basis of hemoglobin, age, WBC count, and chromosomal abnormalities. Several nonrandomized studies have indicated that allogeneic SCT for patients under the age of 55 is effective in prolonging survival in more than 50% of cases and in possibly curing the disease. Patients with the most severe prognosis are candidates.

CONCLUSION

"Consensus" methodology offers a definition of MMM useful for conducting and reporting clinical studies. A detailed knowledge of prognostic factors can help to delineate guidelines for addressing patients with allogeneic SCT.

Long-term cost-effectiveness of low molecular weight heparin versus unfractionated heparin for the prophylaxis of venous thromboembolism in elective hip replacement

BACKGROUND AND OBJECTIVE

Either low molecular weight heparin (LMWH) or unfractionated heparin (UH) may be used for the prophylaxis of post-operative venous thromboembolic disease (VTD) in elective hip replacement. This study was aimed at assessing the cost-effectiveness of LMWH over UH from the society perspective, which considers all the outcomes occurring in the life-long time horizon.

DESIGN AND METHODS

A decision tree modeled the clinical outcomes and resources used in consequence of restricted (2 weeks) and extended (4 weeks) prophylaxis of VTD with LMWH or UH.

RESULTS

In the studied population, that of 67 year-old patients, restricted prophylaxis with LMWH saved 25 quality-adjusted days and $75 over UH. Extended prophylaxis provided a small additional benefit with additional cost savings. The incremental outcomes of the model proved independent of most parameters.

INTERPRETATION AND CONCLUSIONS

We conclude that LMWH has considerable advantages over UH in the prophylaxis of VTD following elective hip replacement, and should be recommended in clinical practice.

Decision support systems in health economics

This article describes a system addressed to different health care professionals for building, using, and sharing decision support systems for resource allocation. The system deals with selected areas, namely the choice of diagnostic tests, the therapy planning, and the instrumentation purchase. Decision support is based on decision-analytic models, incorporating an explicit knowledge representation of both the medical domain knowledge and the economic evaluation theory. Application models are built on top of meta-models, that are used as guidelines for making explicit both the cost and effectiveness components. This approach improves the transparency and soundness of the collaborative decision-making process and facilitates the result interpretation.

A model for analysing the cost of autologous peripheral blood progenitor cell (PBPC) transplantation

Data from autologous peripheral blood progenitor cell (PBPC) transplant recipients were used for cost analysis and modelling so as to link the main intervention procedures and clinical events to resource use and costs. This cohort consisted of 64 patients from 4 to 62 years old at transplantation (mean, 36.9 years) who underwent a first transplant between August 1994 and May 1997. The main indications for transplantation were non-Hodgkin's lymphomas (47%), multiple myeloma (30%) and Hodgkin's lymphomas (15%). The course of a patient during the whole transplant procedure was modelled using a Markov chain of six states of health: (1) mobilisation and recovery of PBPC; (2) post-mobilisation phase; (3) conditioning and transplant; (4) critical haematological reconstitution; (5) non-critical haematological reconstitution; (6) death. The probability of transition between the different health states, together with the estimated costs, were the input for the Markov model. The model also managed transition probabilities depending both on the current health state and on various demographic, clinical and procedure-related covariates unique to the patient. The expected time spent in each clinical state and the expected total cost were, therefore, estimated. This analysis gave an actual total cost per transplanted patient of $26,600 (95% range: $24,700 to $43,500) while mean duration was 197 days. The expenses for in-hospital stay accounted for 80% of the costs. Both the probability of staying in the different states, and the consequent cost were dependent on the number of CD34-positive cells collected, the phase and the type of the disease, the subset of patients (either children or adults), and the post-transplant G-CSF prophylaxis. The sensitivity of the estimates to alternative assumptions was studied, and the method of comparing alternative future scenarios by the model was explored.

The Italian Consensus Conference on Diagnostic Criteria for Myelofibrosis with Myeloid Metaplasia

The purpose of this work was to develop a definition of myelofibrosis with myeloid metaplasia (MMM) using diagnostic criteria that would remain valid within the set of patients with chronic myeloproliferative disorders or myelodysplastic syndromes. A list of 12 names for the disease and 37 diagnostic criteria were proposed to a Consensus Panel of 12 Italian experts who ranked them in order so as to identify a core set of criteria. The Panel was then asked to score the diagnosis of 46 patient profiles as appropriate or not appropriate for MMM. Using the experts' consensus as the gold standard, the performance of 90 possible definitions of the disease obtained through the core set was evaluated. 'Myelofibrosis with myeloid metaplasia' ranked as the preferred name of the disease. Necessary criteria consisted of 'diffuse bone marrow fibrosis' and 'absence of Philadelphia chromosome or BCR-ABL rearrangement in peripheral blood cells'. The six optional criteria in the core set consisted of: splenomegaly of any grade; anisopoikilocytosis with tear-drop erythrocytes; the presence of circulating immature myeloid cells; the presence of circulating erythroblasts: the presence of clusters of megakaryoblasts and anomalous megakaryocytes in bone marrow sections; myeloid metaplasia. The definition of the disease with the highest final score was as follows: necessary criteria plus any other two criteria when splenomegaly is present or any four when splenomegaly is absent. The use of this definition will help to standardize the conduct and reporting of clinical studies and should help practitioners in clinical practice.

A randomized double-blind placebo-controlled study with subcutaneous recombinant human erythropoietin in patients with low-risk myelodysplastic syndromes

To evaluate the effect of recombinant human erythropoietin (rHuEpo) on the haemoglobin level and transfusion requirement in low-risk myelodysplastic syndromes (MDS), 87 patients were enrolled in a randomized double-blind placebo-controlled study, 44 patients were assigned to epoetin alpha (150 U/kg/d s.c. for 8 weeks) and 43 to placebo arms. MDS types were homogenous in both groups: refractory anaemia (RA) 47.7-48.8%. refractory anaemia with ringed sideroblasts (RAS) 20.5-25.6%, refractory anaemia with excess of blasts (RAEB) (blasts < 10%) 31.8-25.6%, 14/38 evaluable patients responded to epoetin alpha versus 4/37 to placebo (P=0.007). 50% of RA responded to epoetin alpha versus 5.9% to placebo (P=0.0072), RAS 37.5% v 18.2% (P=0.6) and RAEB 16.7% v 11.1% (P=1.00). 60% of non-pretransfused patients responded to epoetin alpha (Hb 8.35< or = 0.73 to 10.07+/-1.87 g/dl), whereas a slight decrease was observed in the placebo group (8.4+/-0.66 to 8.19+/-0.92 g/dl) (P=0.0004). Percentage of transfused patients was similar in both arms. Basal erythropoietin (Epo) serum levels > 200 mU/l predicted for a non-response. At week 4 sTfR levels were increased > 50% in responders (P=0.013), whereas an increase < 18% predicted for non-response (P=0.006). Leucocyte and platelet counts were not influenced by epoetin alpha treatment. Adverse events occurred in 31.8% of the rHuEpo-treated versus 42.99%) of the placebo-treated patients (P=0.2), and seven patients did not complete the course. In conclusion, rHuEpo was effective in the treatment of low-risk MDS. RA subtype, no transfusions prior to rHuEpo therapy, and low basal Epo levels were associated with higher probability of response. Soluble transferrin receptor level at the fourth week was an early predictor of response.

Prophylactic splenectomy and cholecystectomy in mild hereditary spherocytosis: analyzing the decision in different clinical scenarios

OBJECTIVES

Patients with mild hereditary spherocytosis (HS), i.e. with haemolysis without anaemia. have an increased risk of gallstone formation, erythroid aplasia and haemolytic crisis. Since the effect of prophylactic splenectomy on life expectancy has not been established, we conducted a decision analysis comparing prophylactic splenectomy and cholecystectomy with no surgery.

DESIGN

The available data on surgery and disease outcomes were modelled to estimate the effects of the different interventions on the quality-adjusted life expectancy. The early phase outcomes depicted surgery-related mortality and incorporated compliance and the adverse effects of prophylaxis against post splenectomy infections. The late phase outcomes were framed by a Markov cohort analysis.

RESULTS

For patients without gallstones, surgery was of no benefit. For those with gallstones the preferred strategies were found to be splenectomy and cholecystectomy before the age of 39 when asymptomatic, and before 52 when accompanied by occasional biliary colic. Cholecystectomy alone proved to be the preferred strategy in older patients with occasional biliary colic. For patients of up to 52 years of age and candidates for cholecystectomy because of recurrent biliary colic, the best strategy was to combine this procedure with splenectomy. Sensitivity analysis showed that the results were sensitive to the incidence of post cholecystectomy syndrome. Most remarkably an extreme sensitivity to compliance with post splenectomy infection prophylaxis was demonstrated.

CONCLUSIONS

Our model suggested that combined prophylactic splenectomy and cholecystectomy provide a substantial gain in quality-adjusted life expectancy for young patients and adults with mild HS and gallstones.