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Dive into the research topics where Michael Gregor is active.

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Featured researches published by Michael Gregor.


The New England Journal of Medicine | 2011

Cytarabine Dose for Acute Myeloid Leukemia

Bob Löwenberg; Thomas Pabst; Edo Vellenga; Wim L.J. van Putten; H Schouten; Carlos Graux; Augustin Ferrant; Pieter Sonneveld; Bart J. Biemond; Alois Gratwohl; Georgine E. de Greef; Leo F. Verdonck; Martijn R. Schaafsma; Michael Gregor; Matthias Theobald; Urs Schanz; Johan Maertens; Gert J. Ossenkoppele

BACKGROUND Cytarabine (ara-C) is an important drug in the treatment of acute myeloid leukemia (AML). High-dose cytarabine (2000 to 3000 mg per square meter of body-surface area) is toxic but results in higher rates of relapse-free survival than does the conventional dose of 100 to 400 mg per square meter. Intermediate dose levels have not been thoroughly evaluated. METHODS We compared two induction regimens in patients 18 to 60 years of age (median, 49) who had newly diagnosed AML. The intermediate-dose group, totaling 431 patients, received cytarabine at a dose of 200 mg per square meter given by continuous intravenous infusion for 24 hours during cycle 1 of induction therapy and 1000 mg per square meter by infusion for 3 hours twice daily during cycle 2 of induction therapy. The high-dose group, totaling 429 patients, received a dose-escalated regimen of 1000 mg of cytarabine per square meter every 12 hours in cycle 1 and 2000 mg per square meter twice daily in cycle 2. Patients with a complete response did not receive additional cytarabine but received consolidation therapy in a third cycle of chemotherapy (mitoxantrone-etoposide) or underwent autologous or allogeneic stem-cell transplantation. Complete remission rates, survival rates, and toxic effects were assessed for each treatment group. RESULTS At a median follow-up of 5 years, no significant differences were noted between the intermediate-dose group and the high-dose group with respect to complete remission rates (80% and 82%, respectively), probability of relapse, event-free survival at 5 years (34% and 35%), or overall survival (40% and 42%). High-dose cytarabine provided no clear advantage in any prognostic subgroup. The high-dose treatment resulted in higher incidences of grade 3 and grade 4 toxic effects (in cycle 1), prolonged hospitalization, and delayed neutrophil recovery (in cycle 2) and platelet recovery (in cycles 2 and 3). CONCLUSIONS Induction therapy with cytarabine at the lower dose already produced maximal antileukemic effects for all response end points, suggesting a plateau in the dose-response relationship above this dose level. High-dose cytarabine results in excessive toxic effects without therapeutic benefit. (Netherlands Trial Register number, NTR230.).


Scandinavian Journal of Infectious Diseases | 2000

C-reactive protein and fever in neutropenic patients.

Caroline Arber; Jakob Passweg; Ursula Flückiger; Miklos Pless; Michael Gregor; André Tichelli; Juerg A. Schifferli; Alois Gratwohl

The predictive value of daily C-reactive protein (CRP) monitoring to distinguish causes of fever in neutropenic patients was studied retrospectively. A total of 143 fever episodes during 113 consecutive hospitalizations were studied in 71 patients who had been referred for chemotherapy or haemopoietic stem cell transplantation (HSCT). There were, on average, 1.3 fever episodes per hospital stay, attributed to: infection (55, 27 invasive bacterial, 5 fungal, 3 viral and 20 probable infections); acute graft vs host disease (GvHD) (20); drugs (22); transfusions (7); and not attributable (39). 130 (91%) fever episodes were accompanied by a rise in CRP, 6 (4%) episodes were fatal. Maximal CRP levels (CRPmax) and maximal temperature (Tmax) were higher in invasive bacterial infections than in aGvHD and higher in aGvHD than in drug- or transfusion-related fever (p < 0.0001). Temperature and CRP rose in parallel. A total of 16 patients developed grade II-IV aGvHD by day 11 (9-21) (median, range) after allogeneic HSCT. Acute GvHD was preceded by fever for 3 d (1-7), and by CRP increase for 5 d (0-15) (p < 0.0001). CRP monitoring may be useful to distinguish between causes of fever. Very high CRP levels tend to be associated with invasive bacterial infections. CRP is not an early warning sign. An increase in CRP and fever may precede other clinical manifestations of aGvHD.The predictive value of daily C-reactive protein (CRP) monitoring to distinguish causes of fever in neutropenic patients was studied retrospectively. A total of 143 fever episodes during 113 consecutive hospitalizations were studied in 71 patients who had been referred for chemotherapy or haemopoetic stem cell transplantation (HSCT). There were, on average, 1.3 fever episodes per hospital stay, attributed to: infection (55, 27 invasive bacterial, 5 fungal, 3 viral and 20 probable infections); acute graft vs host disease (GvHD) (20); drugs (22); transfusions (7); and not attributable (39). 130 (91%) fever episodes were accompanied by a rise in CRP, 6 (4%) episodes were fatal. Maximal CRP levels (CRPmax) and maximal temperature (Tmax) were higher in invasive bacterial infections than in aGvHD and higher in aGvHD than in drug- or transfusion-related fever ( p B 0.0001). Temperature and CRP rose in parallel. A total of 16 patients developed grade II-IV aGvHD by day 11 (9-21) (median, range) after allogeneic HSCT. Acute GvHD was preceded by fever for 3 d (1-7), and by CRP increase for 5 d (0-15) ( p B 0.0001). CRP monitoring may be useful to distinguish between causes of fever. Very high CRP levels tend to be associated with invasive bacterial infections. CRP is not an early warning sign. An increase in CRP and fever may precede other clinical manifestations of aGvHD.


British Journal of Haematology | 1999

Repeated peripheral stem cell mobilization in healthy donors: time-dependent changes in mobilization efficiency

André Tichelli; Jakob Passweg; Till Hoffmann; Michael Gregor; Thomas Kühne; Geneviève Favre; Alexandra Wodnar-Filipowicz; Alois Gratwohl

Mobilization of peripheral blood stem cells was analysed in 10 consecutive healthy donors undergoing repeated stem cell mobilization for allogeneic transplantation. Donors received recombinant G‐CSF at a dose of 10 μg/kg/d for both mobilizations. Collection of stem cells was started on day 5 of G‐CSF administration. To compare the efficiency of first and second mobilization, we determined the leucocyte and CD34+ cell counts in peripheral blood, and the yield of nucleated cells and CD34+ cell counts in the apheresis product. CD34+ cell numbers in peripheral blood were (median) 81.2 × 106/l during the first and 50.4 × 106/l during the second mobilization (P = 0.007). Likewise, CD34+ cells in the apheresis product decreased from 319.8 × 106 to 275.7 × 106 (P = 0.02). Decrease in CD34+ cell counts in peripheral blood and in the apheresis product was associated with the time interval between first and second mobilization. In a regression analysis there was a correlation between the ratios of CD34+ cell counts of first and second mobilization and the inverse of time interval between procedures (r2 = 0.51 peripheral blood; r2 = 0.74 apheresis product). Thus, stem cell yield is reduced when healthy donors receive repeated mobilization within a short time. Nevertheless, an adequate number of stem cells may repeatedly be mobilized within 2 months.


Leukemia & Lymphoma | 2010

Efficacy of rituximab and cladribine in patients with chronic lymphocytic leukemia and feasibility of stem cell mobilization : a prospective multicenter phase II trial (protocol SAKK 34/02)

Nicolas Leupin; Jan C. Schuller; Max Solenthaler; Dominik Heim; Alicia Rovó; Kurt Beretta; Michael Gregor; Mario Bargetzi; Peter Brauchli; Andreas Himmelmann; Silvia Hanselmann; Reinhard Zenhäusern

This phase II trial investigated rituximab and cladribine in chronic lymphocytic leukemia. Four induction cycles, comprising cladribine (0.1 mg/kg/day days 1–5, cycles 1–4) and rituximab (375 mg/m2 day 1, cycles 2–4), were given every 28 days. Stem cell mobilization (rituximab 375 mg/m2 days 1 and 8; cyclophosphamide 4 g/m2 day 2; and granulocyte colony-stimulating factor 10 µg/kg/day, from day 4) was performed in responders. Of 42 patients, nine achieved complete remission (CR), 15 very good partial remission, and two nodular partial remission (overall response rate 62%). Stem cell mobilization and harvesting (≥2×106 stem cells/kg body weight) were successful in 12 of 20 patients. Rituximab infusion-related adverse events were moderate. The main grade 3/4 adverse events during induction were neutropenia and lymphocytopenia. Rituximab plus cladribine was effective; however, the CR rate was modest and stem cell harvest was impaired in a large number of responding patients.


Leukemia Research | 2015

CD34+ selected versus unselected autologous stem cell transplantation in patients with advanced-stage mantle cell and diffuse large B-cell lymphoma

Martin D. Berger; Giacomo Branger; Kurt Leibundgut; Katja Seipel; Beatrice U. Mueller; Michael Gregor; Axel Ruefer; Thomas Pabst

Novel strategies aiming to increase survival rates in patients with advanced-stage mantle cell lymphoma (MCL) and relapsing diffuse large B-cell lymphoma (DLBCL) are a clinical need. High-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) has improved progression-free (PFS) and overall survival (OS) in MCL and relapsed DLBCL. However, the role of CD34+ cell selection before ASCT in MCL and DLBCL is unclear. We retrospectively analyzed the outcome of 62 consecutive patients with advanced-stage MCL or relapsed DLBCL undergoing ASCT with (n=31) or without (n=31) prior CD34+ selection. All patients had stage III or IV disease, with 47% having DLBCL and 53% MCL. The median duration for neutrophil and platelet recovery was 12 and 16 days in CD34+ selected patients, and 11 (P<.001) and 14 days (P=.012) in the group without selection, respectively. No differences in toxicities were observed. The 5-year PFS for CD34+ selected versus not selected patients was 67% and 39% (P=.016), and the 5-year OS was 86% and 54% (P=.007). Our data suggest that using CD34+ selected autografts for ASCT in advanced stage MCL and DLBCL is associated with longer PFS and OS without increased toxicity.


Swiss Medical Weekly | 2010

Integrating novel agents into multiple myeloma treatment - current status in Switzerland and treatment recommendations.

Christian Taverna; Mario Bargetzi; Daniel C. Betticher; Jürg Gmür; Michael Gregor; Dominik Heim; Urs Hess; Nicolas Ketterer; Erika Lerch; Thomas Matthes; Ulrich Mey; Thomas Pabst; Christoph Renner

The treatment of multiple myeloma has undergone significant changes in the recent past. The arrival of novel agents, especially thalidomide, bortezomib and lenalidomide, has expanded treatment options and patient outcomes are improving significantly. This article summarises the discussions of an expert meeting which was held to debate current treatment practices for multiple myeloma in Switzerland concerning the role of the novel agents and to provide recommendations for their use in different treatment stages based on currently available clinical data. Novel agent combinations for the treatment of newly diagnosed, as well as relapsed multiple myeloma are examined. In addition, the role of novel agents in patients with cytogenetic abnormalities and renal impairment, as well as the management of the most frequent side effects of the novel agents are discussed. The aim of this article is to assist in treatment decisions in daily clinical practice to achieve the best possible outcome for patients with multiple myeloma.


European Journal of Haematology | 2011

Hereditary hyperferritinemia‐cataract syndrome (HHCS) presenting with iron deficiency anemia associated with a new mutation in the iron responsive element of the L ferritin gene in a swiss family

Axel Rüfer; Jeremy P. Howell; Alex P. Lange; Raina Yamamoto; Julia Heuscher; Michael Gregor; Walter A. Wuillemin

Hereditary hyperferritinemia‐cataract syndrome (HHCS) is one of the differential diagnoses of hyperferritinemia (HF) with low or normal transferrin saturation but is usually not associated with anemia. Here, we report a case of a microcytic, hypochromic anemia with hyperferritinemia as the initial presentation of a combination of iron deficiency anemia and HHCS. The latter is an autosomal dominant disorder characterized by distinctive cataracts and HF in the absence of iron overload. Sequencing studies were carried out to look for mutations in the iron responsive element (IRE) of the L ferritin gene. A heterozygous single point mutation for a +24T to C substitution in the IRE of the L ferritin gene (=HGVS c.‐176T>C) was detected which has not been described before. To evaluate the pathogenetic relevance of this new mutation, we performed family studies of parents and siblings. We could identify the father and one brother with HF, cataract, and the heterozygous +24T>C mutation. Neither the mother nor the five other siblings had HF, cataract or that mutation. We therefore conclude that this newly described heterozygous +24T>C mutation in the IRE of the L ferritin gene causes HHCS.


Cancer Epidemiology | 2018

Improvement of relative survival in elderly patients with acute myeloid leukaemia emerging from population-based cancer registries in Switzerland between 2001 and 2013

Annatina Schnegg-Kaufmann; Anita Feller; Helen Baldomero; Alicia Rovó; Markus G. Manz; Michael Gregor; Anna Efthymiou; Mario Bargetzi; Urs Hess; Olivier Spertini; Yves Chalandon; Jakob Passweg; Georg Stussi; Volker Arndt; Nicolas Bonadies

Acute Myeloid Leukaemia (AML) is a rare and heterogeneous haematological malignancy with increasing incidence in the elderly. We performed a population-based, observational analysis of AML cases reported to the Cantonal Cancer Registries in Switzerland. Data was aggregated by the National Institute for Epidemiology and Cancer Registration and stratified for the two time periods 2001-2007 and 2008-2013. Overall, 2351 new AML cases were registered with a stable age-standardised incidence rate (3.0 [95 CI: 2.8-3.2] per 100,000 person-years). This indicates that our observed raise of annual AML cases (+10.9%) is mainly related to demographic ageing and not to an increase of age-specific risks. The fraction of non-classifiable AML cases decreased over time (54.6% to 41.8%) but remained high in elderly patients (65-74yrs: 44%; 75-84yrs: 54.2%, 85+yrs: 59.1%), suggesting less accurate diagnostics and reporting with increasing age. 5yrs relative survival (RS) correlated with AML risk class (favorable: 61.7%-68.4%; adverse risk: 11.4%-21.9%) and age (<65yrs: 42.6-43.3%; 75-84yrs: 2.0-3.0%), but improved only modestly overall (19.2% to 23.3%). Interestingly, we identified a significant improvement of RS in patients aged 65-74yrs (5yrs: 5.2% to 13.5%; p<0.001). As surrogate for changes in management, we found an increase of allogeneic haematopoietic stem cell transplantations (1.4 to 7%) and clinical trial activities (25 to 29%) for elderly AML patients during the observation period. Our analysis indicates that recent progress made in management of elderly AML patients results in an improvement of survival on a population-based level in Switzerland and that therapeutic nihilism is not justifiable.


Swiss Medical Weekly | 2007

Rituximab for acute plasma-refractory thrombotic thrombocytopenic purpura. A case report and concise review of the literature.

Axel Rüfer; Doreen Brodmann; Michael Gregor; Johanna A. Kremer Hovinga; Bernhard Lämmle; Walter A. Wuillemin


Cancer Genetics and Cytogenetics | 2005

Polysomy 8 defines a clinico-cytogenetic entity representing a subset of myeloid hematologic malignancies associated with a poor prognosis: report on a cohort of 12 patients and review of 105 published cases

Valérie Beyer; Dominique Mühlematter; Valérie Parlier; Christine Cabrol; Sandrine Bougeon-Mamin; Max Solenthaler; Andreas Tobler; Paul Pugin; Michael Gregor; Felicitas Hitz; Urs Hess; Bernard Chapuis; Urs Schanz; P.M. Schmidt; Guy van Melle; Martine Jotterand

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Urs Hess

Kantonsspital St. Gallen

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André Tichelli

University Hospital of Basel

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