Education and Training:

Medical School, University of Zürich, Switzerland (Diplome Federal) (1990-96) 

M.D.,  Faculty of Medicine, University of Zürich, Switzerland (1997)

Resident, Internal Medicine, Rätisches Kantons- und Regionalspital, Chur, Switzerland (1997-99)

Resident, Internal Medicine, University Hospital, Zürich, Switzerland (1999-02)

Ph.D., University of Washington, Seattle, WA (2006)

Research Fellow, Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA (2002-08)

Fellow, Division of Hematology, University of Washington, Seattle, WA (2005-07)

M.S. (Epidemiology, Clinical Research), University of Washington, Seattle, WA (2011)

CURRENT CLINICAL INTERESTS

Acute Myeloid Leukemia; Myelodysplastic syndromes

CURRENT RESEARCH INTERESTS

Acute myeloid leukemia; Gemtuzumab Ozogamicin; Immunotherapy of AML; Leukemia Stem Cells; Clinical Trials in AML

RESEARCH DESCRIPTION

Dr. Walter’s laboratory research is focused on human acute myeloid leukemia (AML), in particular on the delineation of the clonal origin of AML, the molecular and phenotypic characterization of AML stem and progenitor cells, and the interaction between AML cells in their environment. A long-term goal of his preclinical studies is the development of novel therapeutic strategies aimed to eradicate AML stem and progenitor cells. Findings from such studies are then translated into the clinic and tested in early phase human trials.  

A second research interest of Dr. Walter is the development and conduct of clinical trials in AML. Dr. Walter is currently the Principal Investigator of several early phase clinical trials that test new drugs and drug combinations in AML; some of these trials were the direct consequence of his prior laboratory studies. He also leads a phase 2 study that explores a strategy of outpatient management of selected AML/MDS patients following intensive induction chemotherapy. 

SELECTED PUBLICATIONS

Walter RB, Othus M, Borthakur G, Ravandi F, Cortes JE, Pierce SA, Appelbaum FR, Kantarjian HA, Estey EH. Prediction of early death following induction therapy for newly diagnosed acute myeloid leukemia with pretreatment risk scores: a novel paradigm for treatment assignment. J Clin Oncol 2011; in press.

Walter RB, Milano F, Brasky TM, White E. Long-term use of acetaminophen, aspirin, and other non-steroidal anti-inflammatory drugs and risk of hematologic malignancies: results from the prospective VITamins and Lifestyle (VITAL) study. J Clin Oncol 2011;29:2424-2431.

Walter RB, Gooley TA, Wood BL, Milano F, Fang M, Sorror ML, Estey EH, Salter AI, Lansverk E, Chien JW, Gopal AK, Appelbaum FR, Pagel JM. Impact of pre-transplant minimal residual disease, as detected by multiparametric flow cytometry, on outcome of myeloablative hematopoietic cell transplantation for acute myeloid leukemia. J Clin Oncol 2011;29:1190-1197.

Walter RB, Appelbaum FR, Tallman MS, Weiss NS, Larson RA, Estey EH. Shortcomings in the clinical evaluation of new drugs: acute myeloid leukemia as paradigm. Blood 2010;116:2420-2428.

Walter RB, Alonzo TA, Gerbing RB, Ho PA, Smith FO, Raimondi SC, Hirsch BA, Gamis AS, Franklin JL, Hurwitz CA, Loken MR, Meshinchi S. High expression of the very late antigen (VLA)-4 integrin independently predicts reduced risk of relapse and improved outcome in pediatric acute myeloid leukemia: a report from the Children’s Oncology Group. J Clin Oncol 2010;28:2831-2838.

Walter RB, Kantarjian HM, Huang X, Pierce SA, Sun Z, Gundacker HM, Ravandi F, Faderl SH, Tallman MS, Appelbaum FR, Estey EH. The effect of complete remission (CR) and CR with incomplete platelet recovery (CRp) on outcome in acute myeloid leukemia: a combined Eastern Cooperative Oncology Group (ECOG), Southwest Oncology Group (SWOG), and M.D. Anderson Cancer Center study. J Clin Oncol 2010;28:1766-1771.

Walter RB, Boyle KM, Appelbaum FR, Bernstein ID, Pagel JM. Simultaneously targeting CD45 significantly increases cytotoxicity of the anti-CD33 immunoconjugate, gemtuzumab ozogamicin, against acute myeloid leukemia (AML) cells and improves survival of mice bearing human AML xenografts. Blood 2008;111:4813-4816.

Walter RB, Häusermann P, Raden BW, Teckchandani AM, Kamikura DM, Bernstein ID, Cooper JA. Phosphorylated ITIMs enable ubiquitylation of an inhibitory cell surface receptor. Traffic 2008;9:267-279.

Walter RB, Raden BW, Zeng R, Häusermann P, Bernstein ID, Cooper JA. ITIM-dependent endocytosis of CD33-related siglecs: role of intracellular domain, tyrosine phosphorylation, and the tyrosine phosphatases, Shp1 and Shp2. J Leuk Biol 2008;83:200-211.

Walter RB, Gooley TA, van der Velden VHJ, Loken MR, van Dongen JJM, Flowers DA, Bernstein ID, Appelbaum FR. CD33 expression and P-glycoprotein-mediated drug efflux inversely correlate and predict and clinical outcome in patients with acute myeloid leukemia treated with gemtuzumab ozogamicin monotherapy. Blood 2007;109:4168-4170.

Walter RB, Pirga JL, Cronk M, Mayer S, Appelbaum FR, Banker DE. PK11195, a peripheral benzodiazepine receptor (pBR) ligand, broadly blocks drug efflux to chemosensitize leukemia and myeloma cells by a pBR-independent, direct transporter-modulating mechanism. Blood 2005;106:3584-3593.

Walter RB, Raden BW, Kamikura DM, Cooper JA, Bernstein ID. Influence of CD33 expression levels and ITIM-dependent internalization on gemtuzumab ozogamicin-induced cytotoxicity. Blood 2005:105:1295-1302.

Walter RB, Raden BW, Cronk MR, Bernstein ID, Appelbaum ID, Banker DE. The peripheral benzodiazepine receptor ligand PK11195 overcomes different resistance mechanisms to sensitize AML cells to gemtuzumab ozogamicin. Blood 2004;103:4276-4284.

Walter RB, Raden BW, Hong TC, Flowers DA, Bernstein ID, Linenberger ML. Multidrug resistance protein (MRP) attenuates gemtuzumab ozogamicin-induced cytotoxicity in acute myeloid leukemia cells. Blood 2003;102:1466-1473.