title: Amyloid-β 11C-PiB-PET imaging results from 2 randomized bapineuzumab phase 3 AD trials.
abstract: OBJECTIVE
  To evaluate the effects of bapineuzumab on brain β-amyloid (Aβ) burden using (11)C-Pittsburgh compound B ((11)C-PiB)-PET.
  
  
  METHODS
  Two phase 3 clinical trials, 1 each in apolipoprotein APOE ε4 carriers and noncarriers, were conducted in patients with mild to moderate Alzheimer disease dementia. Bapineuzumab, an anti-Aβ monoclonal antibody, or placebo, was administered by IV infusion every 13 weeks for 78 weeks. PET substudies assessed change in brain fibrillar Aβ over 71 weeks using an (11)C-PiB-PET standardized uptake value ratio (SUVr) global cortical average (GCA) comprising the average SUVr from 5 cortical regions of interest with cerebellar gray matter as the reference region.
  
  
  RESULTS
  A total of 115 carriers and 39 noncarriers were analyzed. The difference (δ) in mean baseline to 71 week change in (11)C-PiB-PET GCA between bapineuzumab and placebo was significant in carriers (0.5 mg/kg vs placebo δ = -0.101; p = 0.004) and in pooled analyses of both carriers and noncarriers (0.5 mg/kg vs placebo δ = -0.068; p = 0.027; 1.0 mg/kg vs placebo δ = -0.133; p = 0.028) but not in the noncarrier trial separately. Analyses by individual region of interest and in mild disease yielded findings similar to the main trial results.
  
  
  CONCLUSIONS
  The (11)C-PiB-PET imaging results demonstrated reduction of fibrillar Aβ accumulation in patients with Alzheimer disease treated with bapineuzumab; however, as no clinical benefit was observed, the findings are consistent with the hypotheses that bapineuzumab may not have been initiated early enough in the disease course, the doses were insufficient, or the most critical Aβ species were inadequately targeted.
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego. eliu12@its.jnj.com.
authors.forename: Enchi
authors.initials: E
authors.lastname: Liu
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Schmidt
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Richard
authors.initials: R
authors.lastname: Margolin
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Reisa
authors.initials: R
authors.lastname: Sperling
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Robert
authors.initials: R
authors.lastname: Koeppe
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Neale S
authors.initials: NS
authors.lastname: Mason
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: William E
authors.initials: WE
authors.lastname: Klunk
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Chester A
authors.initials: CA
authors.lastname: Mathis
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Stephen
authors.initials: S
authors.lastname: Salloway
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Nick C
authors.initials: NC
authors.lastname: Fox
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Derek L
authors.initials: DL
authors.lastname: Hill
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Les
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Peter
authors.initials: P
authors.lastname: Collins
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Gregg
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Jianing
authors.initials: J
authors.lastname: Di
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: I Cristina
authors.initials: IC
authors.lastname: Tudor
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Wyman
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Kevin
authors.initials: K
authors.lastname: Booth
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Broome
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Eric
authors.initials: E
authors.lastname: Yuen
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: Michael
authors.initials: M
authors.lastname: Grundman
authors.affiliation: From Janssen Alzheimer Immunotherapy Research & Development, LLC (E.L., R.M., P.C., K.M.G., J.D., Y.L., I.C.T., S.B., E.Y., H.R.B.), South San Francisco, CA; Janssen Pharmaceutical (M.E.S.), Beerse, NV; Brigham & Women's Hospital (R.S.), Boston, MA; University of Michigan (R.K.), Ann Arbor; University of Pittsburgh (N.S.M., W.E.K., C.A.M.), PA; Butler Hospital (S.S.), Providence, RI; UCL Institute of Neurology (N.C.F.), London, UK; IXICO plc (D.L.H., A.S.L.), London, UK; Pfizer Inc. (B.T.W.), Groton, CT; Pfizer Inc. (K.B.), Collegeville, PA; Global R&D Partners, LLC (M.G.), San Diego, CA; and University of California (M.G.), San Diego.
authors.forename: H Robert
authors.initials: HR
authors.lastname: Brashear
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000187:drug effects / Q000378:metabolism*; D000814:Aniline Compounds; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000494:pharmacology*; D053327:Apolipoprotein E4 / Q000235:genetics; D052160:Benzothiazoles; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D013844:Thiazoles; D016896:Treatment Outcome
chemical_list: C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D061067:Antibodies, Monoclonal, Humanized; D053327:Apolipoprotein E4; D052160:Benzothiazoles; D013844:Thiazoles; C545458:bapineuzumab