Bendamustine followed by obinutuzumab and venetoclax in chronic lymphocytic leukaemia (CLL2-BAG): primary endpoint analysis of a multicentre, open-label, phase 2 trial.

BACKGROUND: Targeted agents such as the type II anti-CD20 antibody obinutuzumab and the B-cell lymphoma-2 antagonist venetoclax have shown impressive therapeutic activity in chronic lymphocytic leukaemia. The CLL2-BAG trial was initiated to investigate the combination of these two agents in patients with chronic lymphocytic leukaemia. METHODS: In this ongoing multicentre, open-label, investigator-initiated phase 2 trial, patients (aged ≥18 years) with chronic lymphocytic leukaemia requiring treatment according to the 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria and an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled at 16 sites in Germany. Patients with a relevant tumour load (absolute lymphocyte count ≥25 000 cells per µL or lymph nodes with a diameter of ≥5 cm) received sequential treatment of debulking with two cycles of bendamustine (70 mg/m2 intravenously on days 1 and 2 of each of the two 28-day cycles), followed by induction and maintenance with obinutuzumab (1000 mg intravenously on days 1-2, 8, and 15 of the first induction cycle, every 4 weeks in induction cycles 2-6, and every 12 weeks in the maintenance phase) and oral venetoclax (starting in induction cycle 2 with 20 mg/day, with a weekly dose escalation over 5 weeks to the target dose of 400 mg/day). The primary endpoint was the proportion of patients achieving an overall response by investigator assessment at the end of induction treatment. All patients who received at least two induction cycles were included in the efficacy analyses and all patients who received at least one dose of study drug were included in the safety analyses. This study is registered with ClinicalTrials.gov, number NCT02401503. FINDINGS: Between May 6, 2015, and Jan 4, 2016, 66 patients were enrolled (35 treatment naive and 31 with relapsed or refractory disease), three of whom were excluded from the efficacy analysis because they received fewer than two induction cycles. Of the remaining 63 patients in the efficacy-evaluable population, 34 patients (54%) were treatment naive and 29 (46%) had relapsed or refractory disease. At data cutoff (Feb 28, 2017), all patients had completed induction treatment. At the end of the induction, 60 (95%) of 63 patients (95% CI 87-99) had responded, including all 34 patients in the treatment-naive cohort and 26 [90%] of 29 relapsed or refractory patients. The most common grade 3-4 adverse events during debulking were neutropenia and anaemia (five [11%] of 47 patients each), and thrombocytopenia and infection (three [6%] each). The most common grade 3-4 adverse events during induction were neutropenia (29 [44%] of 66 patients), infection (nine [14%]), thrombocytopenia (eight [12%]), infusion-related reactions (five [8%]), and secondary primary malignancy (four [6%]). 89 serious adverse events, including 69 related to study treatment, were reported. These serious adverse events were also mainly infections (four cases in four patients during debulking and 18 cases in 11 patients during induction) and cytopenia (four cases in four patients during debulking and ten cases in seven patients in induction). Five relapsed or refractory patients died: three cases of sepsis were deemed related to study treatment, whereas two deaths from Richter's transformation were not. INTERPRETATION: The sequential application of bendamustine and obinutuzumab combined with venetoclax caused no unexpected or cumulative toxicities. The high proportion of patients who achieved overall responses, both treatment-naive and relapsed or refractory patients irrespective of physical fitness and genetic risk factors, compare favourably to established chronic lymphocytic leukaemia therapies. Further follow-up will help to define whether the remissions with eradication of minimal residual disease achieved with this combination are durable after treatment discontinuation. FUNDING: F Hoffmann-La Roche and AbbVie.

Complex karyotypes and KRAS and POT1 mutations impact outcome in CLL after chlorambucil-based chemotherapy or chemoimmunotherapy.

Genetic instability is a feature of chronic lymphocytic leukemia (CLL) with adverse prognosis. We hypothesized that chromosomal translocations or complex karyotypes and distinct somatic mutations may impact outcome after first-line chemoimmunotherapy of CLL patients. We performed metaphase karyotyping and next-generation sequencing (NGS) of 85 genes in pretreatment blood samples obtained from 161 patients registered for CLL11, a 3-arm phase 3 trial comparing frontline chlorambucil (Clb) vs Clb plus rituximab (Clb-R) or Clb plus obinutuzumab in CLL patients with significant comorbidity. Chromosomal aberrations as assessed by karyotyping were observed in 68.8% of 154 patients, 31.2% carried translocations, and 19.5% showed complex karyotypes. NGS revealed 198 missense/nonsense mutations and 76 small indels in 76.4% of patients. The most frequently mutated genes were NOTCH1, SF3B1, ATM, TP53, BIRC3, POT1, XPO1, and KRAS Sole chemotherapy, treatment with Clb-R, or genetic lesions in TP53 (9.9% of patients) and KRAS (6.2% of patients) were significantly associated with nonresponse to study therapy. In multivariate models, complex karyotypes and POT1 mutations (8.1% of patients) represented significant prognostic factors for an unfavorable survival, independently of IGHV mutation status, Binet stage, and serum ß-2-microglobuline. Patients with the copresence of complex karyotypes and deletions/mutations involving TP53 demonstrated a particularly short survival. In summary, this is the first prospective, controlled study in CLL patients that shows a role of complex karyotype aberrations as an independent prognostic factor for survival after front-line therapy. Moreover, the study identifies mutations in KRAS and POT1 as novel determinants of outcome after chemoimmunotherapy using chlorambucil and anti-CD20 treatment.

Long-term remissions after FCR chemoimmunotherapy in previously untreated patients with CLL: updated results of the CLL8 trial.

Despite promising results with targeted drugs, chemoimmunotherapy with fludarabine, cyclophosphamide (FC), and rituximab (R) remains the standard therapy for fit patients with untreated chronic lymphocytic leukemia (CLL). Herein, we present the long-term follow-up of the randomized CLL8 trial reporting safety and efficacy of FC and FCR treatment of 817 treatment-naïve patients with CLL. The primary end point was progression-free survival (PFS). With a median follow-up of 5.9 years, median PFS were 56.8 and 32.9 months for the FCR and FC group (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.50-0.69, P < .001). Median overall survival (OS) was not reached for the FCR group and was 86.0 months for the FC group (HR, 0.68; 95% CI, 0.54-0.89, P = .001). In patients with mutated IGHV (IGHV MUT), FCR improved PFS and OS compared with FC (PFS: HR, 0.47; 95% CI, 0.33-0.68, P < .001; OS: HR, 0.62; 95% CI, 0.34-1.11, P = .1). This improvement remained applicable for all cytogenetic subgroups other than del(17p). Long-term safety analyses showed that FCR had a higher rate of prolonged neutropenia during the first year after treatment (16.6% vs 8.8%; P = .007). Secondary malignancies including Richter's transformation occurred in 13.1% in the FCR group and in 17.4% in the FC group (P = .1). First-line chemoimmunotherapy with FCR induces long-term remissions and highly relevant improvement in OS in specific genetic subgroups of fit patients with CLL, in particular those with IGHV MUT. This trial was registered at www.clinicaltrials.gov as #NCT00281918.

CLL2-BXX Phase II trials: sequential, targeted treatment for eradication of minimal residual disease in chronic lymphocytic leukemia.

AIM: Four Phase II trials (clinical trials numbers: NCT02345863, NCT02401503, NCT02445131 and NCT02689141) evaluate a different combination of targeted agents in an all-comer population of approximately 60 patients with chronic lymphocytic leukemia irrespective of prior treatment, physical fitness and genetic risk factors. Patients with a higher tumor load start with a debulking treatment with bendamustine. The subsequent induction and maintenance treatment with an anti-CD20 antibody (obinutuzumab or ofatumumab) and a targeted oral agent (ibrutinib, idelalisib or venetoclax) are continued until achievement of a complete response and minimal residual disease negativity. CONCLUSION: This strategy represents a new era of chronic lymphocytic leukemia therapy where chemotherapy is increasingly replaced by targeted agents and treatment duration is tailored to the patient's individual tumor load and response.

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.).

Obinutuzumab in chronic lymphocytic leukemia: design, development and place in therapy.

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.