title: Randomized phase 2 study of obinutuzumab monotherapy in symptomatic, previously untreated chronic lymphocytic leukemia.
abstract: Obinutuzumab is a glycoengineered, type 2 anti-CD20 humanized antibody with single-agent activity in relapsed chronic lymphocytic leukemia (CLL). With other CD20 antibodies, a dose-response relationship has been shown. We therefore performed a randomized phase 2 study in symptomatic, untreated CLL patients to evaluate if an obinutuzumab dose response exists. Obinutuzumab was given at a dose of 1000 mg (100 mg IV day 1, 900 mg day 2, 1000 mg day 8 and day 15 of cycle 1; 1000 mg day 1 of cycles 2-8) or 2000 mg (100 mg IV day 1, 900 mg day 2, 1000 mg day 3, 2000 mg day 8 and day 15 of cycle 1; 2000 mg day 1 of cycles 2-8). The primary end point was overall response rate (ORR). Eighty patients were enrolled with similar demographics: median age 67 years, 41% high-risk Rai disease, and 10% del(17p)(13.1). ORR (67% vs 49%, P = .08) and complete response (CR) or CR with incomplete cytopenia response (20% vs 5%) favored 2000 mg obinutuzumab. Overall, therapy was well tolerated, and infusion events were manageable. This study demonstrates significant efficacy of obinutuzumab monotherapy, for 1000 mg as well as for 2000 mg, in untreated CLL patients with acceptable toxicity. Although exploratory, a dose-response relationship may exist, but its relevance to improving progression-free survival is uncertain and will require further follow-up. This trial was registered at www.clinicaltrials.gov as #NCT01414205.
authors.affiliation: Division of Hematology and Comprehensive Cancer Center and Division of Medicinal Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH;
authors.forename: John C
authors.initials: JC
authors.lastname: Byrd
authors.affiliation: Division of Hematology and Comprehensive Cancer Center and.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Flynn
authors.affiliation: Moores Cancer Center, University of California San Diego, La Jolla, CA;
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Kipps
authors.affiliation: Arizona Oncology Associates, Tucson, AZ; US Oncology Research, Vancouver, WA;
authors.forename: Michael
authors.initials: M
authors.lastname: Boxer
authors.affiliation: US Oncology Research, Vancouver, WA; Northwest Cancer Specialists, Vancouver, WA;
authors.forename: Kathryn S
authors.initials: KS
authors.lastname: Kolibaba
authors.affiliation: Roche Innovation Center, Welwyn Garden City, United Kingdom;
authors.forename: David J
authors.initials: DJ
authors.lastname: Carlile
authors.affiliation: F. Hoffmann-La Roche, Pharma Development Oncology, Basel, Switzerland;
authors.forename: Guenter
authors.initials: G
authors.lastname: Fingerle-Rowson
authors.affiliation: F. Hoffmann-La Roche Ltd., Welwyn Garden City, United Kingdom;
authors.forename: Nicola
authors.initials: N
authors.lastname: Tyson
authors.affiliation: Genentech Inc., South San Francisco, CA; and.
authors.forename: Jamie
authors.initials: J
authors.lastname: Hirata
authors.affiliation: US Oncology Research, Vancouver, WA; Willamette Valley Cancer Institute and Research Center, Eugene, OR.
authors.forename: Jeff P
authors.initials: JP
authors.lastname: Sharman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012074:Remission Induction; D015996:Survival Rate; D014018:Tissue Distribution
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; C543332:obinutuzumab