Ibrutinib plus obinutuzumab versus chlorambucil plus obinutuzumab in first-line treatment of chronic lymphocytic leukaemia (iLLUMINATE): a multicentre, randomised, open-label, phase 3 trial

Obinutuzumab and ibrutinib induction therapy followed by a minimal residual disease-driven strategy in patients with chronic lymphocytic leukaemia (ICLL07 FILO): a single-arm, multicentre, phase 2 trial

BACKGROUND

In patients with chronic lymphocytic leukaemia, achievement of a complete response with minimal residual disease of less than 0·01% (ie, <1 chronic lymphocytic leukaemia cell per 10 000 leukocytes) in bone marrow has been associated with improved progression-free survival. We aimed to explore the activity of induction therapy for 9 months with obinutuzumab and ibrutinib, followed up with a minimal residual disease-driven therapeutic strategy for 6 additional months, in previously untreated patients.

METHODS

We did a single-arm, phase 2 trial in 27 university hospitals, general hospitals, and specialist cancer centres in France. Eligible patients were at least 18 years old and previously untreated, and had immunophenotypically confirmed B-cell chronic lymphocytic leukaemia; an Eastern Cooperative Oncology Group (ECOG) performance status score of less than 2; a Binet stage C according to IWCLL 2008 criteria or Binet stage A and B with active disease; no 17p deletion or absence of p53 mutation; and were considered medically fit. In the first part of the study (induction phase), all participants received eight intravenous infusions of obinutuzumab 1000 mg over six 4-weekly cycles and oral ibrutinib 420 mg once per day for 9 months. In part 2, after assessment on day 1 of month 9, patients with a complete response and bone marrow minimal residual disease of less than 0·01% received only oral ibrutinib 420 mg once per day for 6 additional months. Patients with a partial response, or with a complete response and bone marrow minimal residual disease of 0·01% or more, received 6 months of four 4-weekly cycles of intravenous fludarabine, cyclophosphamide, and obinutuzumab 1000 mg, alongside continuing ibrutinib 420 mg once per day. The primary endpoint was the proportion of patients achieving a complete response with bone marrow minimal residual disease less than 0·01% on day 1 of month 16 assessed by intention to treat (ITT). This trial is registered with ClinicalTrials.gov (number NCT02666898) and is still open for follow-up.

FINDINGS

Between Oct 27, 2015, and May 16, 2017, 135 patients were enrolled. After induction treatment (day 1 of month 9), 130 patients were evaluable, of which ten (8%) achieved a complete response with bone marrow minimal residual disease of less than 0·01% and were assigned to ibrutinib, and 120 (92%) were assigned to ibrutinib plus fludarabine, cyclophosphamide, and obinutuzumab. After minimal residual disease-guided treatment (day 1 of month 16), 84 (62%, 90% CI 55-69) of 135 patients (ITT population) achieved a complete response with bone marrow minimal residual disease of less than 0·01%. The most common haematological adverse event was thrombocytopenia (in 45 [34%] of 133 patients at grade 1-2 in months 1-9 and in 43 [33%] of 130 patients at grade 1-2 in months 9-15). The most common non-haematological adverse events were infusion-related reactions (in 83 [62%] patients at grade 1-2 in months 1-9) and gastrointestinal disorders (in 62 [48%] patients at grades 1 and 2 in months 9-15). 49 serious adverse events occurred, most frequently infections (ten), cardiac events (eight), and haematological events (eight). No treatment-related deaths occurred.

INTERPRETATION

Obinutuzumab and ibrutinib induction therapy followed by a minimal residual disease driven strategy is safe and active in patients with previously untreated chronic lymphocytic leukaemia. With longer follow-up, including assessing the evolution of minimal residual disease, if response is maintained, this strategy could be an option in the first-line setting in patients with chronic lymphocytic leukaemia, although randomised evidence is needed.

FUNDING

Roche, Janssen.

Updates in the management of chronic lymphocytic leukemia/small lymphocytic leukemia

Chronic lymphocytic leukemia is one of the most common lymphoid malignancies. Often treatment modalities are tailored to individual patients based on age, presence of comorbidities and cytogenetics. The advent of ibrutinib has significantly changed the management of the disease in all patient groups and has had the largest impact on clinical practice to date. Over the last 15 years, a series of trials have established that chemoimmunotherapy improves both progression-free survival and overall survival compared to chemotherapy alone. Despite its proven role, efficacy of ibrutinib has not been well established in young, fit patients and in comparison with standard care and as combination therapy with other agents such as venetoclax. New data have strengthened the role of ibrutinib in the front-line setting and establish its place in therapy. In addition, combination therapies are geared to achieve negative minimal residual disease and allow patients to potentially be off of therapy. The management of this leukemia has extensively changed over the past years, and this review article will aim to highlight key trials that have changed practice and led to guideline updates. It is not unlikely that treatment modalities will continue to improve in light of new data.

Venetoclax and Obinutuzumab in Patients with CLL and Coexisting Conditions

BACKGROUND

The BCL2 inhibitor venetoclax has shown activity in patients with chronic lymphocytic leukemia (CLL), but its efficacy in combination with other agents in patients with CLL and coexisting conditions is not known.

METHODS

In this open-label, phase 3 trial, we investigated fixed-duration treatment with venetoclax and obinutuzumab in patients with previously untreated CLL and coexisting conditions. Patients with a score of greater than 6 on the Cumulative Illness Rating Scale (scores range from 0 to 56, with higher scores indicating more impaired function of organ systems) or a calculated creatinine clearance of less than 70 ml per minute were randomly assigned to receive venetoclax-obinutuzumab or chlorambucil-obinutuzumab. The primary end point was investigator-assessed progression-free survival. The safety of each regimen was also evaluated.

RESULTS

In total, 432 patients (median age, 72 years; median Cumulative Illness Rating Scale score, 8; median creatinine clearance, 66.4 ml per minute) underwent randomization, with 216 assigned to each group. After a median follow-up of 28.1 months, 30 primary end-point events (disease progression or death) had occurred in the venetoclax-obinutuzumab group and 77 had occurred in the chlorambucil-obinutuzumab group (hazard ratio, 0.35; 95% confidence interval [CI], 0.23 to 0.53; P<0.001). The Kaplan-Meier estimate of the percentage of patients with progression-free survival at 24 months was significantly higher in the venetoclax-obinutuzumab group than in the chlorambucil-obinutuzumab group: 88.2% (95% CI, 83.7 to 92.6) as compared with 64.1% (95% CI, 57.4 to 70.8). This benefit was also observed in patients with TP53 deletion, mutation, or both and in patients with unmutated immunoglobulin heavy-chain genes. Grade 3 or 4 neutropenia occurred in 52.8% of patients in the venetoclax-obinutuzumab group and in 48.1% of patients in the chlorambucil-obinutuzumab group, and grade 3 or 4 infections occurred in 17.5% and 15.0%, respectively. All-cause mortality was 9.3% in the venetoclax-obinutuzumab group and 7.9% in the chlorambucil-obinutuzumab group. These differences were not significant.

CONCLUSIONS

Among patients with untreated CLL and coexisting conditions, venetoclax-obinutuzumab was associated with longer progression-free survival than chlorambucil-obinutuzumab. (Funded by F. Hoffmann-La Roche and AbbVie; ClinicalTrials.gov number, NCT02242942.).

Tailored Treatment Strategies for Chronic Lymphocytic Leukemia in a Rapidly Changing Era

The treatment landscape for chronic lymphocytic leukemia (CLL) is rapidly evolving, with multiple agents recently approved. They include a glycoengineered monoclonal antibody (obinutuzumab), B-cell receptor signaling inhibitors (ibrutinib, idelalisib, and duvelisib), and the BCL-2 inhibitor (venetoclax). These compounds are dramatically changing the natural course of the disease. Nonetheless, despite improved survival rates, particularly in higher-risk disease (older adults, patients with unmutated IGHV, del(11q), and del(17p)/TP53 mutated), there is still room for progress. Given the panoply of highly effective therapies commercially available, it is important to define a tailored treatment strategy for this heterogeneous condition that considers balance of treatment efficacy versus toxicity or tolerance. This article summarizes the most promising clinical advances by reviewing the data from recent clinical trials and discussing meaningful clinical endpoints, including the role of minimal residual disease assessment. The recent development of therapies targeting dysregulated pathways is revolutionary and may ultimately lead us to not only achieve prolonged remission durations but also envision the possibility of a functional cure for a larger population of patients.

Treating Older Patients with Chronic Lymphocytic Leukemia: A Personalized Approach

Median age at diagnosis for patients with chronic lymphocytic leukemia (CLL) is 72 years, and the number of older individuals affected by this condition is predicted to increase in the future as populations age. Contrary to common assumptions, CLL significantly affects the life expectancy of older individuals, frequently presenting at a more advanced stage and with more unfavorable features than in the younger population. Therefore, identifying the optimal treatment for these patients is a priority. Older patients with CLL are usually classified as fit, non-fit, or frail based on performance status and comorbidities, and several assessment tools can be used to make these evaluations. While supportive care is appropriate for frail patients, the remaining patients should be treated when indication criteria are met. Treatment options include chemoimmunotherapy, monoclonal antibody-based approaches (such as the use of rituximab, ofatumumab, or obinutuzumab) and, more recently, small molecules (such as ibrutinib, idelalisib, and venetoclax). The choice of treatment is guided by the patient's performance status and co-morbidities and by the disease characteristics, such as chromosomal and molecular abnormalities, and in patients with recurrent disease also by the type of prior regimen, their tolerability, and duration of response.

Ibrutinib for the treatment of chronic lymphocytic leukemia

INTRODUCTION

Chemoimmunotherapy has improved outcomes in chronic lymphocytic leukemia, yet it is not curative, with very high relapse rates, and is associated with a significant risk of toxicities. Moreover, patients with higher-risk genetic abnormalities continue to experience poorer outcomes and lower survival. Recently, novel targeted therapies have been developed to increase efficacy and reduce toxicity. Areas covered: Ibrutinib is an oral irreversible inhibitor of Bruton's tyrosine kinase, a mediator of B-cell receptor signaling, which plays a vital role in various B-cell neoplasms. The drug has been approved for the treatment of several hematological malignancies, including chronic lymphocytic leukemia/small lymphocytic lymphoma, where large trials have shown outcomes never seen before even in high-risk patients. The safety profile appeared furthermore favorable, even in elderly and unfit patients. Expert opinion: Therapy with ibrutinib rarely provides MRD-negative complete remission; an indefinite maintenance is therefore needed, with the risk of developing adverse events (AE) or resistance resulting in treatment interruption or discontinuation. Novel, extremely promising, combination strategies, based on the association of ibrutinib with chemoimmunotherapy, anti-CD20 monoclonal antibody or other targeted agents, are currently being investigated, with the goal of achieving greater depth of remission, especially MRD-negativity, and removing the need for indefinite treatment.

From Biology to Therapy: The CLL Success Story

Chemoimmunotherapy has been the standard of care for patients with chronic lymphocytic leukemia (CLL) over the last decade. Advances in monoclonal antibody technology have resulted in the development of newer generations of anti-CD20 antibodies with improved therapeutic effectiveness. In parallel, our knowledge about the distinctive biological characteristics of CLL has progressively deepened and has revealed the importance of B-cell receptor (BCR) signaling and upregulated antiapoptotic proteins for survival and expansion of malignant cell clones. This knowledge provided the basis for development of novel targeted agents that revolutionized treatment of CLL. Ibrutinib and idelalisib inhibit the Bruton tyrosine kinase (BTK) and phosphoinositide 3-kinase (PI3K) delta, respectively, thus interfering with supportive signals coming from the microenvironment via the BCR. These drugs induce egress of CLL cells from secondary lymphoid organs and remarkably improve clinical outcomes, especially for patients with unmutated immunoglobulin heavy-chain genes or with p53 abnormalities that do not benefit from classical treatment schemes. Latest clinical trial results have established ibrutinib with or without anti-CD20 antibodies as the preferred first-line treatment for most CLL patients, which will reduce the use of chemoimmunotherapy in the imminent future. Further advances are achieved with venetoclax, a BH3-mimetic that specifically inhibits the antiapoptotic B-cell lymphoma 2 protein and thus causes rapid apoptosis of CLL cells, which translates into deep and prolonged clinical responses including high rates of minimal residual disease negativity. This review summarizes recent advances in the development of targeted CLL therapies, including new combination schemes, novel BTK and PI3K inhibitors, spleen tyrosine kinase inhibitors, immunomodulatory drugs, and cellular immunotherapy.

Application of a sequential multiple assignment randomized trial (SMART) design in older patients with chronic lymphocytic leukemia

BACKGROUND

Ibrutinib therapy is safe and effective in patients with chronic lymphocytic leukemia (CLL). Currently, ibrutinib is administered continuously until disease progression. Combination regimens with ibrutinib are being developed to deepen response which could allow for ibrutinib maintenance (IM) discontinuation. Among untreated older patients with CLL, clinical investigators had the following questions: (i) does ibrutinib + venetoclax + obinutuzumab (IVO) with IM have superior progression-free survival (PFS) compared with ibrutinib + obinutuzumab (IO) with IM, and (ii) does the treatment strategy of IVO + IM for patients without minimal residual disease complete response (MRD- CR) or IVO + IM discontinuation for patients with MRD- CR have superior PFS compared with IO + IM.

DESIGN

Conventional designs randomize patients to IO with IM or IVO with IM to address the first objective, or randomize patients to each treatment strategy to address the second objective. A sequential multiple assignment randomized trial (SMART) design and analysis is proposed to address both objectives.

RESULTS

A SMART design strategy is appropriate when comparing adaptive interventions, which are defined by an individual's sequence of treatment decisions and guided by intermediate outcomes, such as response to therapy. A review of common applications of SMART design strategies is provided. Specific to the SMART design previously considered for Alliance study A041702, the general structure of the SMART is presented, an approach to sample size and power calculations when comparing adaptive interventions embedded in the SMART with a time-to-event end point is fully described, and analyses plans are outlined.

CONCLUSION

SMART design strategies can be used in cancer clinical trials with adaptive interventions to identify optimal treatment strategies. Further, standard software exists to provide sample size, power calculations, and data analysis for a SMART design.

Phase 1b study of venetoclax-obinutuzumab in previously untreated and relapsed/refractory chronic lymphocytic leukemia

This single-arm, open-label, phase 1b study evaluated the maximum tolerated dose (MTD) of venetoclax when given with obinutuzumab and its safety and tolerability in patients with relapsed/refractory (R/R) or previously untreated (first line [1L]) chronic lymphocytic leukemia (CLL). Venetoclax dose initially was escalated (100-400 mg) in a 3 + 3 design to define MTD combined with standard-dose obinutuzumab. Patients received venetoclax (schedule A) or obinutuzumab (schedule B) first to compare safety and determine dose/schedule for expansion. Venetoclax-obinutuzumab was administered for 6 cycles, followed by venetoclax monotherapy until disease progression (R/R) or fixed duration 1-year treatment (1L). Fifty R/R and 32 1L patients were enrolled. No dose-limiting toxicities were observed. Safety, including incidence of tumor lysis syndrome (TLS), did not differ between schedules (2 laboratory TLSs per schedule). Schedule B and a 400-mg dose of venetoclax were chosen for expansion. The most common grade 3-4 adverse event was neutropenia (R/R, 58% of patients; 1L, 53%). Rates of grade 3-4 infections were 29% (R/R) and 13% (1L); no fatal infections occurred in 1L. All infusion-related reactions were grade 1-2, except for 2 grade 3 events. No clinical TLS was observed. Overall best response rate was 95% in R/R (complete response [CR]/CR with incomplete marrow recovery [CRi], 37%) and 100% in 1L (CR/CRi, 78%) patients. Rate of undetectable (<10^-4) minimal residual disease (uMRD) in peripheral blood for R/R and 1L patients, respectively, was 64% and 91% ≥3 months after last obinutuzumab dose. Venetoclax and obinutuzumab therapy had an acceptable safety profile and elicited durable responses and high rates of uMRD. This trial was registered at www.clinicaltrials.gov as #NCT01685892.

Protoporphyrin IX is a dual inhibitor of p53/MDM2 and p53/MDM4 interactions and induces apoptosis in B-cell chronic lymphocytic leukemia cells

p53 is a tumor suppressor, which belongs to the p53 family of proteins. The family consists of p53, p63 and p73 proteins, which share similar structure and function. Activation of wild-type p53 or TAp73 in tumors leads to tumor regression, and small molecules restoring the p53 pathway are in clinical development. Protoporphyrin IX (PpIX), a metabolite of aminolevulinic acid, is a clinically approved drug applied in photodynamic diagnosis and therapy. PpIX induces p53-dependent and TAp73-dependent apoptosis and inhibits TAp73/MDM2 and TAp73/MDM4 interactions. Here we demonstrate that PpIX is a dual inhibitor of p53/MDM2 and p53/MDM4 interactions and activates apoptosis in B-cell chronic lymphocytic leukemia cells without illumination and without affecting normal cells. PpIX stabilizes p53 and TAp73 proteins, induces p53-downstream apoptotic targets and provokes cancer cell death at doses non-toxic to normal cells. Our findings open up new opportunities for repurposing PpIX for treating lymphoblastic leukemia with wild-type TP53.

Ibrutinib increases the risk of hypertension and atrial fibrillation: Systematic review and meta-analysis

Introduction

Ibrutinib is an oral covalent inhibitor of Bruton's tyrosine kinase approved for the treatment of patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma and Waldenstrӧm’s macroglobulinemia. Ibrutinib has an increased risk of atrial fibrillation but the mechanism is unknown, and hypertension may play a role in the pathogenesis of this adverse drug reaction.

Methods

We aimed to review the risk of hypertension and atrial fibrillation as adverse events associated with ibrutinib through a systematic review with meta-analysis of randomized controlled trials (RCTs) retrieved in December 2018 on MEDLINE, EMBASE, CENTRAL and ClinicalTrials.gov. The data were pooled using random-effects meta-analyses using the risk ratio (RR) with the 95% confidence interval (95%CI). The confidence on the pooled estimates was ascertained through the grading of recommendations assessment, development, and evaluation (GRADE) approach.

Results

There were 8 eligible RCTs (2580 patients), all reporting safety data of interest. Ibrutinib was associated with a significant increase in the risk of hypertension with a RR of 2.82 (95%CI 1.52–5.23) with moderate quality evidence. Ibrutinib increased significantly the risk of atrial fibrillation with a RR of 4.69 (95%CI 2.17–7.64) with high quality evidence.

Conclusions

Ibrutinib was associated with significantly increased risks of both hypertension and atrial fibrillation.