Michael K. Wenger

Obinutuzumab plus Chlorambucil in Patients with CLL and Coexisting Conditions

BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.).

Rituximab Plus Fludarabine and Cyclophosphamide Prolongs Progression-Free Survival Compared With Fludarabine and Cyclophosphamide Alone in Previously Treated Chronic Lymphocytic Leukemia

PURPOSE Rituximab, a monoclonal antibody that targets the CD20 cell surface antigen, has clinical activity in patients with non-Hodgkins lymphoma and other B-lymphocyte disorders when administered alone or in combination with chemotherapy. Promising results have previously been reported in nonrandomized studies in patients with chronic lymphocytic leukemia (CLL). This trial was designed to compare chemoimmunotherapy with chemotherapy alone in patients with previously treated CLL. PATIENTS AND METHODS This international, multicenter, randomized trial compared six cycles of rituximab plus fludarabine and cyclophosphamide (R-FC) with six cycles of fludarabine and cyclophosphamide alone (FC) in patients with previously treated CLL. A total of 552 patients with Binet stage A (1%), B (59%), or C (31%) disease entered the study and were randomly assigned to receive R-FC (n = 276) or FC (n = 276). RESULTS After a median follow-up time of 25 months, rituximab significantly improved progression-free survival in patients with previously treated CLL (hazard ratio = 0.65; P < .001; median, 30.6 months for R-FC v 20.6 months for FC). Event-free survival, response rate, complete response rate, duration of response, and time to new CLL treatment or death were also significantly improved. Although the rates of adverse events, grade 3 or 4 events, and serious adverse events were slightly higher in the R-FC arm, R-FC was generally well tolerated, with no new safety findings and no detrimental effect on quality of life. CONCLUSION R-FC significantly improved the outcome of patients with previously treated CLL.

Minimal Residual Disease Quantification Is an Independent Predictor of Progression-Free and Overall Survival in Chronic Lymphocytic Leukemia: A Multivariate Analysis From the Randomized GCLLSG CLL8 Trial

PURPOSE To determine the clinical significance of flow cytometric minimal residual disease (MRD) quantification in chronic lymphocytic leukemia (CLL) in addition to pretherapeutic risk factors and to compare the prognostic impact of MRD between the arms of the German CLL Study Group CLL8 trial. PATIENTS AND METHODS MRD levels were prospectively quantified in 1,775 blood and bone marrow samples from 493 patients randomly assigned to receive fludarabine and cyclophosphamide (FC) or FC plus rituximab (FCR). Patients were categorized by MRD into low- (< 10(-4)), intermediate- (≥ 10(-4) to <10(-2)), and high-level (≥ 10(-2)) groups. RESULTS Low MRD levels during and after therapy were associated with longer progression-free survival (PFS) and overall survival (OS; P < .0001). Median PFS is estimated at 68.7, 40.5, and 15.4 months for low, intermediate, and high MRD levels, respectively, when assessed 2 months after therapy. Compared with patients with low MRD, greater risks of disease progression were associated with intermediate and high MRD levels (hazard ratios, 2.49 and 14.7, respectively; both P < .0001). Median OS was 48.4 months in patients with high MRD and was not reached for lower MRD levels. MRD remained predictive for OS and PFS in multivariate analyses that included the most important pretherapeutic risk markers in CLL. PFS and OS did not differ between treatment arms within each MRD category. However, FCR induced low MRD levels more frequently than FC. CONCLUSION MRD levels independently predict OS and PFS in CLL. Therefore, MRD quantification might serve as a surrogate marker to assess treatment efficacy in randomized trials before clinical end points can be evaluated.

Gene mutations and treatment outcome in chronic lymphocytic leukemia: results from the CLL8 trial

Mutations in TP53, NOTCH1, and SF3B1 were analyzed in the CLL8 study evaluating first-line therapy with fludarabine and cyclophosphamide (FC) or FC with rituximab (FCR) among patients with untreated chronic lymphocytic leukemia (CLL). TP53, NOTCH1, and SF3B1 were mutated in 11.5%, 10.0%, and 18.4% of patients, respectively. NOTCH1(mut) and SF3B1(mut) virtually showed mutual exclusivity (0.6% concurrence), but TP53(mut) was frequently found in NOTCH1(mut) (16.1%) and in SF3B1(mut) (14.0%) patients. There were few significant associations with clinical and laboratory characteristics, but genetic markers had a strong influence on response and survival. In multivariable analyses, an independent prognostic impact was found for FCR, thymidine kinase (TK) ≥10 U/L, unmutated IGHV, 11q deletion, 17p deletion, TP53(mut), and SF3B1(mut) on progression-free survival; and for FCR, age ≥65 years, Eastern Cooperative Oncology Group performance status ≥1, β2-microglobulin ≥3.5 mg/L, TK ≥10 U/L, unmutated IGHV, 17p deletion, and TP53(mut) on overall survival. Notably, predictive marker analysis identified an interaction of NOTCH1 mutational status and treatment in that rituximab failed to improve response and survival in patients with NOTCH1(mut). In conclusion, TP53 and SF3B1 mutations appear among the strongest prognostic markers in CLL patients receiving current-standard first-line therapy. NOTCH1(mut) was identified as a predictive marker for decreased benefit from the addition of rituximab to FC. This study is registered at www.clinicaltrials.gov as #NCT00281918.

The role of sex and weight on rituximab clearance and serum elimination half-life in elderly patients with DLBCL

Pharmacokinetics of 8 doses of rituximab (375 mg/m(2)) given in combination with 2-week cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone/prednisolone (CHOP-14) was determined by ELISA in 20 elderly patients with diffuse large B-cell lymphoma (DLBCL) 10 minutes before and after each infusion and 1 week and 1, 2, 3, 6, and 9 months after the last infusion. Population pharmacokinetic modeling was performed with nonlinear mixed-effect modeling software (NONMEM VI). Concentration-time data were fitted into an open 2-compartment model and total clearance, central compartment volume, intercompartment clearance, and volume of distribution at steady-state (Vd(ss)) were investigated. Total clearance was 9.43 mL/h and Vd(ss) was 9.61 l. Rituximab clearance was reduced (8.21 mL/h vs 12.68 mL/h; P = .003) and elimination half-life was prolonged in women compared with men (t(1/2β) = 30.7 vs 24.7 days; P = .003). Body weight also affected Vd(ss) (0.1 l increase of Vd(ss) per kilogram above median of 75 kg). A sex-dependent effect and the higher weight of males contribute to their faster rituximab clearance, which might explain why elderly males benefit less from the addition of rituximab to CHOP than females. This trial was registered on www.clinicaltrials.gov as numbers NCT00052936, EU-20243 (RICOVER-60 Trial), EU-20534, and NCT00726700 (Pegfilgrastim Trial).

Obinutuzumab (GA101) in Patients With Relapsed/Refractory Indolent Non-Hodgkin Lymphoma: Results From the Phase II GAUGUIN Study

PURPOSE The phase II part of the phase I/II GAUGUIN study evaluated the efficacy and safety of two different doses of obinutuzumab (GA101), a type II, glycoengineered, humanized anti-CD20 monoclonal antibody, in patients with relapsed/refractory indolent non-Hodgkin lymphoma. PATIENTS AND METHODS Patients were randomly assigned to receive eight cycles of obinutuzumab (GA101) as a flat dose of 400 mg on days 1 and 8 of cycle 1 and also on day 1 of cycles 2 to 8 (400/400 mg) or 1,600 mg on days 1 and 8 of cycle 1 and 800 mg on day 1 of cycles 2 to 8 (1,600/800 mg). RESULTS Forty patients were enrolled, including 34 with follicular lymphoma; 38 of 40 patients had previously received rituximab and 22 of 40 were rituximab refractory. The overall response rate at the end of treatment was 55% (95% CI, 32% to 76%) in the 1,600/800-mg group (9% complete responders) and 17% (95% CI, 4% to 41%) in the 400/400-mg group (no complete responders). Five of 10 rituximab-refractory patients had an end-of-treatment response in the 1,600/800-mg group versus one of 12 in the 400/400-mg group. Median progression-free survival was 11.9 months in the 1,600/800-mg group (range, 1.8 to 33.9+ months) and 6.0 months in the 400/400-mg group (range, 1.0 to 33.9+ months). The most common adverse events were infusion-related reactions (IRRs) seen in 73% of patients, but only two patients had grade 3 to 4 IRRs (both in the 1,600/800-mg group). No IRRs were considered serious, and no patients withdrew for IRRs. CONCLUSION The 1,600/800-mg dose schedule of obinutuzumab (GA101) has encouraging activity with an acceptable safety profile in relapsed/refractory indolent non-Hodgkin lymphoma.

Obinutuzumab (GA101) in relapsed/refractory chronic lymphocytic leukemia: final data from the phase 1/2 GAUGUIN study

GAUGUIN evaluated the safety and efficacy of obinutuzumab (GA101) monotherapy in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). In phase 1 (dose escalation), 13 patients received obinutuzumab 400 to 1200 mg (days 1 and 8 of cycle 1; day 1 of cycles 2-8). In phase 2, 20 patients received a fixed dose of 1000 mg (days 1, 8, and 15 of cycle 1; day 1 of cycles 2-8). Infusion-related reactions occurred in nearly all patients, but few were grade 3/4. Grade 3/4 neutropenia occurred in 7 patients in phase 1 (but was not dose-related) and in 4 patients in phase 2. Overall end-of-treatment response (all partial responses) was 62% (phase 1) and 15% (phase 2); best overall response was 62% and 30%, respectively. Phase 2 median progression-free survival was 10.7 months and median duration of response was 8.9 months. In summary, obinutuzumab monotherapy is active in patients with heavily pretreated relapsed/refractory CLL.

Obinutuzumab (GA101) plus CHOP or FC in relapsed/refractory follicular lymphoma: results of the GAUDI study (BO21000)

The safety and activity of obinutuzumab (GA101) plus chemotherapy in relapsed/refractory follicular lymphoma was explored in 56 patients. Participants received obinutuzumab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (G-CHOP; every 3 weeks for 6 to 8 cycles) or obinutuzumab plus fludarabine and cyclophosphamide (G-FC; every 4 weeks for 4 to 6 cycles). Patients were randomly assigned to either obinutuzumab 1600 mg on days 1 and 8 of cycle 1 followed by 800 mg on day 1 of subsequent cycles or 400 mg for all doses. Treatment responders were eligible for obinutuzumab maintenance every 3 months for up to 2 years. Grade 1/2 infusion-related reactions (IRRs) were the most common treatment-related adverse event (AE) (all grades: G-CHOP, 68%; G-FC, 82%). Grade 3/4 IRRs were rare (7%) and restricted to the first infusion. All patients received the planned obinutuzumab dose. Neutropenia was the most common treatment-related hematologic AE for G-CHOP (43%) and G-FC (50%). At induction end, 96% (27/28) of patients receiving G-CHOP (complete response [CR], 39% [11/28]) and 93% (26/28) receiving G-FC (CR, 50% [14 of 28]) achieved responses. G-CHOP and G-FC had an acceptable safety profile with no new or unexpected AEs, but G-FC was associated with more AEs than G-CHOP. Obinutuzumab plus chemotherapy resulted in 93% to 96% response rates, supporting phase 3 investigation. This trial was registered at www.clinicaltrials.gov as #NCT00825149.

Obinutuzumab for the First-Line Treatment of Follicular Lymphoma

BACKGROUND Rituximab‐based immunochemotherapy has improved outcomes in patients with follicular lymphoma. Obinutuzumab is a glycoengineered type II anti‐CD20 monoclonal antibody. We compared rituximab‐based chemotherapy with obinutuzumab‐based chemotherapy in patients with previously untreated advanced‐stage follicular lymphoma. METHODS We randomly assigned patients to undergo induction treatment with obinutuzumab‐based chemotherapy or rituximab‐based chemotherapy. Patients with a response received maintenance treatment for up to 2 years with the same antibody that they had received in induction. The primary end point was investigator‐assessed progression‐free survival. RESULTS A total of 1202 patients with follicular lymphoma underwent randomization (601 patients in each group). After a median follow‐up of 34.5 months (range, 0 to 54.5), a planned interim analysis showed that obinutuzumab‐based chemotherapy resulted in a significantly lower risk of progression, relapse, or death than rituximab‐based chemotherapy (estimated 3‐year rate of progression‐free survival, 80.0% vs. 73.3%; hazard ratio for progression, relapse, or death, 0.66; 95% confidence interval [CI], 0.51 to 0.85; P=0.001). Similar results were seen with regard to independently reviewed progression‐free survival and other time‐to‐event end points. Response rates were similar in the two groups (88.5% in the obinutuzumab group and 86.9% in the rituximab group). Adverse events of grade 3 to 5 were more frequent in the obinutuzumab group than in the rituximab group (74.6% vs. 67.8%), as were serious adverse events (46.1% vs. 39.9%). The rates of adverse events resulting in death were similar in the two groups (4.0% in the obinutuzumab group and 3.4% in the rituximab group). The most common adverse events were infusion‐related events that were considered by the investigators to be largely due to obinutuzumab in 353 of 595 patients (59.3%; 95% CI, 55.3 to 63.2) and to rituximab in 292 of 597 patients (48.9%; 95% CI, 44.9 to 52.9; P<0.001). Nausea and neutropenia were common. A total of 35 patients (5.8%) in the obinutuzumab group and 46 (7.7%) in the rituximab group died. CONCLUSIONS Obinutuzumab‐based immunochemotherapy and maintenance therapy resulted in longer progression‐free survival than rituximab‐based therapy. High‐grade adverse events were more common with obinutuzumab‐based chemotherapy. (Funded by F. Hoffmann–La Roche; GALLIUM ClinicalTrials.gov number, NCT01332968.)

Effect of FCGR2A and FCGR3A variants on CLL outcome

Polymorphisms of activating Fc-γ receptors (FCGRs) on natural killer cells and macrophages result in variable affinity for immunoglobulin G1 monoclonal antibodies and subsequently modulate antibody-dependent cellular cytotoxicity (ADCC) activity. Whether single-nucleotide polymorphisms of FCGRs correlate with survival of chronic lymphocytic leukemia (CLL) patients treated with a monoclonal antibody containing regimen is unclear. We assessed the FCGR3A and FCGR2A genotype of patients enrolled in the REACH trial, where patients received fludarabine and cyclophosphamide (FC) or rituximab plus FC (R-FC). FCGR3A and FCGR2A polymorphisms did not demonstrate prognostic significance in the FC arm (P = .42 and P = .64, respectively) or R-FC arm (P = .41 and P = .88, respectively) with respect to progression free survival. Patients with intermediate affinity genotypes (FV and HR) benefited significantly from addition of rituximab (hazard ratio = 0.55 [0.37-0.8 CI]; P = .0017 and hazard ratio = 0.63 [0.44-0.9 CI]; P = .011, respectively). Similar benefit was suggested for patients with high- affinity VV and HH (hazard ratio = 0.86 [0.4-1.84 CI]; P = .7 and hazard ratio = 0.7 [0.41-1.18 CI]; P = .18, respectively) and low-affinity FF and RR (hazard ratio = 0.85 [0.56-1.29 CI]; P = .44 and hazard ratio = 0.82 [0.47-1.42 CI]; P = .48, respectively). Overall, our results suggest that FCGR2A and FCGR3A polymorphisms do not significantly influence the outcomes of relapsed or refractory CLL patients treated with FC or the monoclonal antibody regimen R-FC.