Hanne Vestergaard

Improved detection of the KIT D816V mutation in patients with systemic mastocytosis using a quantitative and highly sensitive real-time qPCR assay.

The vast majority of patients with systemic mastocytosis (SM) carry the somatic D816V mutation in the KIT gene. The KIT D816V mutation is one of the minor criteria for a diagnosis of SM according to the 2008 World Health Organization classification of myeloproliferative neoplasms. In the present study, we present a real-time qPCR assay that allows quantification of as little as 0.003% KIT D816V mutation-positive cells. A total of 61 samples from 31 cases of SM were included in the study. We detected the mutation in skin or bone marrow in 95% of the cases of SM. We demonstrate the clinical relevance of the assay by identifying as little as 0.03% mutation-positive cells in bone marrow aspirates from SM patients and calculate the analytical sensitivity of negative samples to determine the reliability of the result. We further demonstrate that this method also detects the KIT D816V mutation in peripheral blood in 81% of the mutation-positive cases with SM. The method also allows comparison of mutation-positive and mast cell fractions to determine whether the mutation is present in non-mast cells, a parameter that has recently been reported to be of prognostic importance in patients with indolent SM. Finally, the assay is suitable for use in prospective studies of the KIT D816V allele burden as a treatment endpoint in SM.

Epidemiology of systemic mastocytosis in Denmark

Mastocytosis is a heterogeneous group of diseases characterized by abnormal proliferation of mast cells. Systemic mastocytosis (SM), in which abnormal mast cells are present in tissues beyond the skin, is divided into seven subcategories with varying degrees of severity and prognosis. Very little is known about the epidemiology of SM and its subcategories. This retrospective cohort study of 548 adults with SM diagnosed 1997–2010 was constructed using linked Danish national health registries. The most common subtype of mastocytosis was indolent SM (including urticaria pigmentosa) (n = 450; 82%), followed by SM with subtype unknown (n = 61; 11%), SM with associated clonal haematological non‐mast cell lineage disease (n = 24; 4%), aggressive SM (n = 8; 2%), and mast cell leukaemia (n = 5; 1%). The incidence rate for SM (all subtypes including urticaria pigmentosa) was 0·89 per 100 000 per year. Cumulative incidence was 12·46 per 100 000, and the 14‐year limited‐duration prevalence as of 1 January, 2011 was 9·59 per 100 000. This nationwide cohort from Denmark is the first population‐based epidemiological study of mastocytosis. In this cohort of patients aged 15 years and older, SM was found to be overall relatively rare with notable variation by subtype for patient characteristics, survival and epidemiological measures.

Autoimmune pulmonary alveolar proteinosis: Treatment options in year 2013

Pulmonary alveolar proteinosis (PAP) is a rare lung disease characterized by accumulation of a periodic acid Schiff (PAS)‐positive eosinophilic material in the distal airways. For decades, the standard treatment of PAP has been whole lung lavage (WLL), where large quantities of saline are instilled into the lungs to remove the proteinaceous material. However, not all patients respond to this treatment. Thus, new treatment modalities, such as subcutaneous or inhaled granulocyte macrophage colony‐stimulating factor (GM‐CSF), and the CD20 antibody rituximab and plasmapheresis, have been investigated. Based on the current literature, a stepwise treatment plan is suggested starting with WLL, continuing to inhaled GM‐CSF, and then to rituximab if the former treatment regimes are unsuccessful.

Long term molecular responses in a cohort of Danish patients with essential thrombocythemia, polycythemia vera and myelofibrosis treated with recombinant interferon alpha.

Within recent years data has accumulated demonstrating the efficacy of recombinant interferon alpha2 (rIFN-alpha2) in the treatment of chronic myeloproliferative neoplasms (MPNs). We report on clinical and molecular data in the largest cohort of JAK2 V617F mutant MPN Danish patients (n=102) being treated long-term with rIFN-alpha2 (rIFN-alpha2a and rIFN-alpha2b in a non-clinical trial setting. The median follow-up was 42 months. We substantiate the capacity of rIFN-alpha2 to induce complete hematologic remissions (ET 95%, PV 68%) and molecular response. In total 76 patients (74.5%) had a decline in JAK2 V617F allele burden with a median reduction from baseline of 59% (95% c.i. 50-73%, range 3-99%). A decline in JAK2 V617F allele burden was recorded in both ET (median 24-10% (95% c.i.: 8-16%), and PV (median 59-35% (95% c.i.: 17-33%). Patients with the lowest pre-treatment JAK2 V617F allele burdens tend to achieve the most favourable responses on long term treatment with rIFN-alpha2. Eleven patients (10%) had deep molecular remissions with ≤ 2% JAK2 V617F mutant DNA. Finally, long term treatment with rIFN-alpha2 was associated with a very low thrombosis rate. Our observations are supportive of the concept of early up-front treatment with rIFN-alpha2.

A phase III randomized trial comparing glucocorticoid monotherapy versus glucocorticoid and rituximab in patients with autoimmune haemolytic anaemia

The impact of first‐line treatment with the anti‐CD 20 chimeric monoclonal antibody rituximab in patients with warm‐antibody reactive autoimmune haemolytic anaemia (WAIHA) is unknown. We report the first randomized study of 64 patients with newly diagnosed WAIHA who received prednisolone and rituximab combined (N = 32) or prednisolone monotherapy (N = 32). After 12 months, a satisfactory response was observed in 75% of the patients treated with rituximab and prednisolone but in a significantly smaller proportion (36%) of those given prednisolone alone (P = 0·003). Furthermore, relapse‐free survival was significantly better after the combined therapy than after prednisolone monotherapy (P = 0·02). After 36 months, about 70% of the patients were still in remission in the rituximab‐prednisolone group, whereas only about 45% were still in complete or partial remission in the prednisolone group. There was no significant difference between the two groups regarding adverse reactions to the studied medications. Likewise, serious adverse events were equally distributed, and no allergic reactions to rituximab were recorded. In conclusion, our data show that using rituximab and prednisolone combined rather than prednisolone alone as first‐line treatment in WAIHA increases both the rate and the duration of the response.

A phase II study of vorinostat (MK-0683) in patients with polycythaemia vera and essential thrombocythaemia

Inhibition of histone deacetylases may be an important target in patients with myeloproliferative neoplasms. This investigator‐initiated, non‐randomized, open‐label phase II multi‐centre study included 63 patients (19 essential thrombocythaemia, 44 polycythaemia vera) from 15 centres. The primary objective was to evaluate if vorinostat was followed by a decline in clonal myeloproliferation as defined by European Leukaemia Net. Thirty patients (48%) completed the intervention period (24 weeks of therapy). An intention‐to‐treat response rate of 35% was identified. Pruritus was resolved [19% to 0% (P = 0·06)] and the prevalence of splenomegaly was lowered from 50% to 27% (P = 0·03). Sixty‐five per cent of the patients experienced a decrease in JAK2 V617F allele burden (P = 0·006). Thirty‐three patients (52% of patients) discontinued study drug before end of intervention due to adverse events (28 patients) or lack of response (5 patients). In conclusion, vorinostat showed effectiveness by normalizing elevated leucocyte and platelet counts, resolving pruritus and significantly reducing splenomegaly. However, vorinostat was associated with significant side effects resulting in a high discontinuation rate. A lower dose of vorinostat in combination with conventional and/or novel targeted therapies may be warranted in future studies.

Clinical effect of increasing doses of lenalidomide in high-risk myelodysplastic syndrome and acute myeloid leukemia with chromosome 5 abnormalities

Background Patients with chromosome 5 abnormalities and high-risk myelodysplastic syndromes or acute myeloid leukemia have a poor outcome. We hypothesized that increasing doses of lenalidomide may benefit this group of patients by inhibiting the tumor clone, as assessed by fluorescence in situ hybridization for del(5q31). Design and Methods Twenty-eight patients at diagnosis or with relapsed disease and not eligible for standard therapy (16 with acute myeloid leukemia, 12 with intermediate-risk 2 or high-risk myelodysplastic syndrome) were enrolled in this prospective phase II multicenter trial and treated with lenalidomide up to 30 mg daily for 16 weeks. Three patients had isolated del(5q), six had del(5q) plus one additional aberration, 14 had del(5q) and a complex karyotype, four had monosomy 5, and one had del(5q) identified by fluorescence in situ hybridization only. Results Major and minor cytogenetic responses, assessed by fluorescence in situ hybridization, were achieved in 5/26 (19%) and 2/26 (8%) patients, respectively, who received one or more dose of lenalidomide, while two patients achieved only a bone marrow response. Nine of all 26 patients (35%) and nine of the ten who completed the 16 weeks of trial responded to treatment. Using the International Working Group criteria for acute myeloid leukemia and myelodysplastic syndrome the overall response rate in treated patients with acute myeloid leukemia was 20% (3/15), while that for patients with myelodysplastic syndrome was 36% (4/11). Seven patients stopped therapy due to progressive disease and nine because of complications, most of which were disease-related. Response rates were similar in patients with isolated del(5q) and in those with additional aberrations. Interestingly, patients with TP53 mutations responded less well than those without mutations (2/13 versus 5/9, respectively; P=0.047). No responses were observed among 11 cases with deleterious TP53 mutations. Conclusions Our data support a role for higher doses of lenalidomide in poor prognosis patients with myelodysplastic syndrome and acute myeloid leukemia with deletion 5q. (Clinicaltrials.gov identifier NCT00761449).

Sensitive KIT D816V mutation analysis of blood as a diagnostic test in mastocytosis

The recent progress in sensitive KIT D816V mutation analysis suggests that mutation analysis of peripheral blood (PB) represents a promising diagnostic test in mastocytosis. However, there is a need for systematic assessment of the analytical sensitivity and specificity of the approach in order to establish its value in clinical use. We therefore evaluated sensitive KIT D816V mutation analysis of PB as a diagnostic test in an entire case‐series of adults with mastocytosis. We demonstrate for the first time that by using a sufficiently sensitive KIT D816V mutation analysis, it is possible to detect the mutation in PB in nearly all adult mastocytosis patients. The mutation was detected in PB in 78 of 83 systemic mastocytosis (94%) and 3 of 4 cutaneous mastocytosis patients (75%). The test was 100% specific as determined by analysis of clinically relevant control patients who all tested negative. Mutation analysis of PB was significantly more sensitive than serum tryptase >20 ng/mL. Of 27 patients with low tryptase, 26 tested mutation positive (96%). The test is furthermore readily available and we consider the results to serve as a foundation of experimental evidence to support the inclusion of the test in diagnostic algorithms and clinical practice in mastocytosis. Am. J. Hematol. 89:493–498, 2014.

Circulating KITD816V mutation-positive non-mast cells in peripheral blood are characteristic of indolent systemic mastocytosis

It is presently accepted that the KIT D816V mutation is detectable in tissues with neoplastic mast cells in most patients with indolent systemic mastocytosis. In this study, neoplastic mast cells were detected in bone marrow, but not in peripheral blood, by flow cytometry in all 25 included cases of indolent systemic mastocytosis. However, the KIT D816V mutation was detected using mutation‐specific qPCR in both bone marrow and peripheral blood in all 25 cases, demonstrating for the first time that the KIT D816V mutation is consistently present in non‐mast cells in indolent systemic mastocytosis and that these cells are circulating in peripheral blood.

KIT D816V mutation burden does not correlate to clinical manifestations of indolent systemic mastocytosis

BACKGROUND Clinical manifestations of indolent systemic mastocytosis (ISM) comprise mediator-related symptoms, anaphylaxis, and osteoporosis. A new sensitive method for KIT D816V mutation detection allows quantification of the level of mutation-positive cells. OBJECTIVE To investigate whether the fraction of KIT D816V positive cells in peripheral blood (PB) or bone marrow (BM) aspirate in adult patients with ISM correlates with clinical manifestations of the disease. METHODS We included 48 adult patients with ISM (28 females/20 males) from our center in whom the KIT D816V mutation level in both BM aspirate and PB was analyzed. For each patient, the severity of mediator-related symptoms (skin, gastrointestinal, musculoskeletal, and neuropsychiatric) and episodes of anaphylaxis were evaluated by interview and medical record files. Bone mineral density was determined by using dual-energy x-ray absorptiometry. RESULTS Median fraction (range) of KIT D816V positive cells was 0.6 (0.01%-90%) in BM and 0.3 (0.003%-49%) in PB. Mutation level did not differ between patients with none/mild symptoms and patients with moderate/severe symptoms, patients with and without anaphylaxis, or patients with osteoporosis/osteopenia and normal bone mineral density. No significant differences in clinical profile were detected in patients with different levels of mutation except for an indication of longer disease duration and age in patients with highest mutation levels. CONCLUSION To our knowledge, this is the first report on the clinical impact of the fraction of KIT D816V mutation positive cells in ISM, which in the present study does not seem to correlate with clinical manifestations of the disease.