Abstract: For decades, treatment of chronic lymphocytic leukemia (CLL) has been based on chemotherapy. This changed when the first CD20 antibody rituximab was introduced. Since 2008, the combination of chemotherapy and CD20 antibodies has become the standard of care for most patients, and a significant fraction of patients had very long-lasting remissions after chemoimmunotherapy. Despite the improvement of response rates and overall survival (OS) by the use of chemoimmunotherapy, most CLL patients will relapse eventually. One approach to achieve more durable responses was the development of obinutuzumab (GA101), a new type of CD20 antibody that has unique molecular and functional characteristics. Obinutuzumab is a type II fully humanized CD20 antibody that binds to a partly different epitope of the CD20 protein than rituximab and due to its glycoengineered design induces greater antibody-dependent cell-mediated cytotoxicity (ADCC). Initial preclinical observations of a more effective B-cell depletion have been successfully reproduced in clinical trials with CLL patients. This review summarizes results of preclinical as well as clinical studies with obinutuzumab and provides an outlook on its future role in the therapy of CLL. Keywords: chronic lymphocytic leukemia, GA101, obinutuzumab, CD20 antibody
The monoclonal anti-CD20 antibody rituximab, combined with chemotherapeutic agents, has been shown to prolong overall survival in physically fit patients with previously untreated chronic lymphocytic leukemia (CLL) but not in those with coexisting conditions. We investigated the benefit of the type 2, glycoengineered antibody obinutuzumab (also known as GA101) as compared with that of rituximab, each combined with chlorambucil, in patients with previously untreated CLL and coexisting conditions.We randomly assigned 781 patients with previously untreated CLL and a score higher than 6 on the Cumulative Illness Rating Scale (CIRS) (range, 0 to 56, with higher scores indicating worse health status) or an estimated creatinine clearance of 30 to 69 ml per minute to receive chlorambucil, obinutuzumab plus chlorambucil, or rituximab plus chlorambucil. The primary end point was investigator-assessed progression-free survival.The patients had a median age of 73 years, creatinine clearance of 62 ml per minute, and CIRS score of 8 at baseline. Treatment with obinutuzumab-chlorambucil or rituximab-chlorambucil, as compared with chlorambucil monotherapy, increased response rates and prolonged progression-free survival (median progression-free survival, 26.7 months with obinutuzumab-chlorambucil vs. 11.1 months with chlorambucil alone; hazard ratio for progression or death, 0.18; 95% confidence interval [CI], 0.13 to 0.24; P<0.001; and 16.3 months with rituximab-chlorambucil vs. 11.1 months with chlorambucil alone; hazard ratio, 0.44; 95% CI, 0.34 to 0.57; P<0.001). Treatment with obinutuzumab-chlorambucil, as compared with chlorambucil alone, prolonged overall survival (hazard ratio for death, 0.41; 95% CI, 0.23 to 0.74; P=0.002). Treatment with obinutuzumab-chlorambucil, as compared with rituximab-chlorambucil, resulted in prolongation of progression-free survival (hazard ratio, 0.39; 95% CI, 0.31 to 0.49; P<0.001) and higher rates of complete response (20.7% vs. 7.0%) and molecular response. Infusion-related reactions and neutropenia were more common with obinutuzumab-chlorambucil than with rituximab-chlorambucil, but the risk of infection was not increased.Combining an anti-CD20 antibody with chemotherapy improved outcomes in patients with CLL and coexisting conditions. In this patient population, obinutuzumab was superior to rituximab when each was combined with chlorambucil. (Funded by F. Hoffmann-La Roche; ClinicalTrials.gov number, NCT01010061.).
7004 Background: Chemoimmunotherapy (CIT) is standard of care in young and physically fit patients (pts) with CLL. Development of CIT for older and less fit CLL pts is ongoing, but data from phase III trials are sparse. CLL11 is the largest trial to evaluate three treatments in previously untreated CLL pts with comorbidities: Clb alone, GA101 + Clb (GClb), R + Clb (RClb). The final analysis of CLL11 stage 1 efficacy and safety results is presented here. Methods: Treatment-naïve CLL pts with a Cumulative Illness Rating Scale (CIRS) total score >6 and/or an estimated creatinine clearance (CrCl) <70 mL/min were eligible. Pts received Clb alone (0.5 mg/kg po d1, d15 q28 days, 6 cycles), GClb (100 mg iv d1, 900 mg d2, 1000 mg d8, d15 of cycle 1, 1000 mg d1 cycles 2-6), or RClb (375 mg/m 2 iv d1 cycle 1, 500 mg/m 2 d1 cycles 2-6). Primary endpoint was investigator-assessed progression-free survival (PFS). Results: Median age, CIRS score, and CrCl at baseline were 73 years, 8, and 61.1 mL/min for stage 1a (Clb vs GClb, 356 pts) and 73 years, 8, and 62.1 mL/min for stage 1b (Clb vs RClb, 351 pts, triggered by a different event rate). Key efficacy and safety results are shown in the Table.Grade 3-4 infusion-related reactions with GClb occurred at first infusion only. Management required splitting the first dose over 2 days. Conclusions: CIT with GClb or RClb significantly prolongs PFS vs Clb alone. The results demonstrate that GClb and RClb are very active in CLL and superior treament options in this population. GClb vs RClb will be compared in stage 2 analysis with more follow-up available. Clinical trial information: NCT01010061. [Table: see text]
improve the classification of the disease and will lead to therapeutic biomarkers.In fact, there is a clinical need to extend our current limited therapeutic portfolio by the detection of innovative therapeutic targets. 20 In the interest of our patients, we hope that these efforts will extend our therapeutic armamentarium in the near future and will offer truly personalized approaches.
