title: Dose-fractionated radioimmunotherapy in non-Hodgkin's lymphoma using DOTA-conjugated, 90Y-radiolabeled, humanized anti-CD22 monoclonal antibody, epratuzumab.
abstract: OBJECTIVE
  Fractionated radioimmunotherapy may improve therapeutic outcome by decreasing heterogeneity of the dose delivered to the tumor and by decreasing hematologic toxicity, thereby allowing an increased amount of radionuclide to be administered. Because humanized anti-CD22 epratuzumab can be given repeatedly, a single-center study was conducted to establish the feasibility, safety, optimal dosing, and preliminary efficacy of weekly administrations of 90Y-labeled 1,4,7,10-tetra-azacyclodecane-N,N',N'',N'''-tetraacetic acid-conjugated epratuzumab.
  
  
  METHODS
  Cohorts of three to six patients with B-cell lymphoma received 185 MBq/m2 [90Y]epratuzumab with unconjugated epratuzumab (total protein dose 1.5 mg/kg) once weekly for two to four infusions, with [(111)In]epratuzumab coadministered at first infusion for scintigraphic imaging and dosimetry.
  
  
  RESULTS
  Sixteen patients received treatment without significant infusional reactions. The overall objective response rate was 62% (95% confidence interval, 39-86%) in both indolent (75%) and aggressive disease (50%). Complete responses (CR/CRu) occurred in 25% of patients and were durable (event-free survival, 14-41 months). Two patients receiving four infusions had hematologic dose-limiting toxicity. Serum epratuzumab levels increased with each weekly dose. Of 13 patients with tumor cell CD22 expression determined by flow cytometry, seven of eight with strongly positive results had objective responses, versus one of five with negative or weakly positive results (P = 0.032).
  
  
  CONCLUSIONS
  Radioimmunotherapy with weekly 185 MBq/m2 [90Y]epratuzumab achieved a high objective response rate (62%) across lymphoma subtypes, including durable CRs. The findings that three weekly infusions (555 MBq/m2, total dose) can be administered safely with only minor toxicity, that antibody levels increased during treatment weeks, and that therapeutic response predominantly occurs in patients with unequivocal CD22 tumor expression provide guidance for future studies.
authors: Department of Oncology, Lund University Hospital, Lund, Sweden. ola.linden@onk.lu.se
authors: Ola
authors: O
authors: Lindén
authors: Cecilia
authors: C
authors: Hindorf
authors: Eva
authors: E
authors: Cavallin-Ståhl
authors: William A
authors: WA
authors: Wegener
authors: David M
authors: DM
authors: Goldenberg
authors: Heather
authors: H
authors: Horne
authors: Tomas
authors: T
authors: Ohlsson
authors: Lars
authors: L
authors: Stenberg
authors: Sven-Erik
authors: SE
authors: Strand
authors: Jan
authors: J
authors: Tennvall
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D015703:Antigens, CD / Q000096:biosynthesis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000096:biosynthesis; D015815:Cell Adhesion Molecules / Q000096:biosynthesis; D018572:Disease-Free Survival; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007262:Infusions, Intravenous; D037102:Lectins / Q000096:biosynthesis; D008228:Lymphoma, Non-Hodgkin / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D016499:Radioimmunotherapy; D051918:Sialic Acid Binding Ig-like Lectin 2; D016896:Treatment Outcome; D015021:Yttrium Radioisotopes / Q000627:therapeutic use
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C497867:CD22 protein, human; D015815:Cell Adhesion Molecules; D037102:Lectins; D051918:Sialic Acid Binding Ig-like Lectin 2; D015021:Yttrium Radioisotopes; C448700:epratuzumab