Impact of targeted therapy on outcome of chronic lymphocytic leukemia patients with relapsed del(17p13.1) karyotype at a single center

Efficacy and Safety of Ibrutinib in Indian Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia and Mantle Cell Lymphoma: Cases from a Named Patient Program

Context:

This named patient program evaluated the safety and efficacy of ibrutinib, a selective inhibitor of Bruton's tyrosine kinase in Indian patients with relapsed/refractory chronic lymphocytic leukemia (CLL, with/without chromosome 17 deletion [del17p]) and mantle cell lymphoma (MCL).

Subjects and Methods:

The eight enrolled patients (relapsed/refractory CLL: n = 6 [4/6 patients with del17p] and relapsed/refractory MCL: n = 2) had median age of 55 years (range, 52–60) and had received a median of 3 (CLL patients) and 4 (MCL patients) prior therapies. Patients received once-daily dose of ibrutinib (420 mg: CLL, 560 mg: MCL).

Results:

In CLL patients, the median time to response was 3 months (range, 0.5–7) and five of six patients had partial response (PR) whereas one achieved complete response (CR). Median time on treatment was 11.5 months (range, 8–14); five patients continued treatment and one was recommended stem cell transplantation (SCT). Of the two MCL patients, one achieved PR and one showed CR and advanced to SCT. In CLL patients, the median (range) hemoglobin level improved from 9.8 g/dL (7.2–11) at baseline to 12.0 g/dL (9.5–13.2) and median (range) platelet count improved from 150,000 cells/μL (21,000–195,000) at baseline to 190,350 cells/μL (130,000–394,000) at the time of analysis (July 2016). Most adverse events (AEs) reported were infections (n = 2). No Grade 3-4 or serious AEs, dose reductions, or treatment discontinuation due to AEs were reported.

Conclusions:

In this first real-world experience in Indian patients, ibrutinib demonstrated therapeutic efficacy in relapsed/refractory CLL (with/without del17p) and MCL. Safety results were consistent with the current known profile of ibrutinib.

Advances in chronic lymphocytic leukemia pharmacotherapy

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease that affects B lymphocytes in most cases. Leukemic lymphocytes have prolonged longevity, defined by resistance to apoptosis. These cells can accumulate in peripheral blood, bone marrow, and solid lymphoid organs. CLL may be indolent or aggressive and has a range of prognostic factors such as expression of CD38 and ZAP-70, immunophenotypic and cytogenetic changes, imbalanced apoptosis proteins, and others. Although CLL has a low mortality rate, this disease is generally not considered curable until today. CLL treatment involves alkylating agents and glucocorticoids, purine analogs, monoclonal antibody therapies, and bone marrow transplantation. In recent decades, new drugs have appeared focusing on new targets and specific molecules, such as the BCR receptor, Bruton's tyrosine kinase, phosphatidylinositol 3-kinase, spleen tyrosine kinase, apoptosis proteins and microRNAs. The most appropriate treatment for CLL is one that involves in its protocol a combination of drugs according to the prognostic factors presented by each patient. In this sense, treatment individualization is essential. This article examines standard treatments for CLL and explores new treatments and potential new targets, as well as schematic protocols to understand where we are, how the treatment has evolved, and the advantages and disadvantages of new targets for CLL therapy.

Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Lymphoid Neoplasms

Lymphoid neoplasms show great diversity in morphology, immunophenotypic profile, and postulated cells of origin, which also reflects the variety of genetic alterations within this group of tumors. This review discusses many of the currently known genetic alterations in selected mature B-cell and T-cell lymphoid neoplasms, and their significance as diagnostic, prognostic, and therapeutic markers. Given the rapidly increasing number of genetic alterations that have been described in this group of tumors, and that the clinical significance of many is still being studied, this is not an entirely exhaustive review of all of the genetic alterations that have been reported.

Present and future of personalized medicine in CLL

Medicine has been 'personalized' (i.e. centred in persons) since its foundation. Recently, however, the term 'personalized medicine' (or, better, 'precision medicine') has been introduced to define 'a form of medicine that uses information about a person's genes, proteins, and environment to prevent, diagnose, and treat disease'. This concept has gained momentum thanks to next-generation-sequencing (NGS) techniques that allow identification of molecular characteristics unique to the patient and to the tumour. It is hoped that NGS will not only contribute to a better understanding of chronic lymphocytic leukaemia (CLL), but will identify disease subsets that could benefit from specific treatment interventions. Recent advances in diagnosis (e.g. high-resolution immunophenotyping, markers of genetic abnormalities), prognosis (e.g. biomarkers), response predictors [e.g. del(17p)/TP53 mutations even at subclonal level], treatment (e.g. BCR signalling inhibitors, BCL2 antagonists, CAR-T cells) and methods to evaluate minimal residual disease constitute good examples of tools facilitating 'personalized' management of patients with CLL.

Vincristine activates c-Jun N-terminal kinase in chronic lymphocytic leukaemia in vivo

AIMS

The authors' aim was to conduct a proof-of-principle study to test whether c-Jun N-terminal kinase (JNK) phosphorylation and Noxa induction occur in peripheral blood chronic lymphocytic leukaemia (CLL) cells in patients receiving a vincristine infusion.

METHODS

Patients with CLL received 2 mg vincristine by a 5-min intravenous infusion. Blood samples were collected at baseline and up to 6 h after the vincristine infusion, and assayed for JNK activation, Noxa induction and vincristine plasma concentrations.

RESULTS

Ex vivo treated peripheral CLL cells activated JNK in response to 10-100 nM vincristine in 6 h. Noxa protein expression, while variable, was also observed over this time frame. In CLL patients, vincristine infusion led to rapid (<1 h) JNK phosphorylation in peripheral blood CLL cells which was sustained for at least 4-6 h after the vincristine infusion. Noxa protein expression was not observed in response to vincristine infusion.

CONCLUSIONS

This study confirmed that vincristine can activate JNK but not induce Noxa in CLL cells in vivo. The results suggest that novel JNK-dependent drug combinations with vincristine warrant further investigation.

Three-year follow-up of treatment-naïve and previously treated patients with CLL and SLL receiving single-agent ibrutinib

Ibrutinib is an orally administered inhibitor of Bruton tyrosine kinase that antagonizes B-cell receptor, chemokine, and integrin-mediated signaling. In early-phase studies, ibrutinib demonstrated high response rates and prolonged progression-free survival (PFS) in chronic lymphocytic leukemia (CLL). The durable responses observed with ibrutinib relate in part to a modest toxicity profile that allows the majority of patients to receive continuous therapy for an extended period. We report on median 3-year follow-up of 132 patients with symptomatic treatment-naïve and relapsed/refractory CLL or small lymphocytic lymphoma. Longer treatment with ibrutinib was associated with improvement in response quality over time and durable remissions. Toxicity with longer follow-up diminished with respect to occurrence of grade 3 or greater cytopenias, fatigue, and infections. Progression remains uncommon, occurring primarily in some patients with relapsed del(17)(p13.1) and/or del(11)(q22.3) disease. Treatment-related lymphocytosis remains largely asymptomatic even when persisting >1 year and does not appear to alter longer-term PFS and overall survival compared with patients with partial response or better. Collectively, these data provide evidence that ibrutinib controls CLL disease manifestations and is well tolerated for an extended period; this information can help direct potential treatment options for different subgroups to diminish the long-term risk of relapse.

Managing high-risk CLL during transition to a new treatment era: stem cell transplantation or novel agents?

Allogeneic hematopoietic stem cell transplantation (HSCT) has been considered as the treatment of choice for patients with high-risk chronic lymphocytic leukemia (HR-CLL; ie, refractory to purine analogs, short response [<24 months] to chemoimmunotherapy, and/or presence of del[17p]/TP53 mutations). Currently, treatment algorithms for HR-CLL are being challenged by the introduction of novel classes of drugs. Among them, BCR signal inhibitors (BCRi) and B-cell lymphoma 2 antagonists (BCL2a) appear particularly promising. As a result of the growing body of favorable outcome data reported for BCRi/BCL2a, uncertainty is emerging on how to advise patients with HR-CLL about indication for and timing of HSCT. This article provides an overview of currently available evidence and theoretical considerations to guide this difficult decision process. Until the risks and benefits of different treatment strategies are settled, all patients with HR-CLL should be considered for treatment with BCRi/BCL2a. For patients who respond to these agents, there are 2 treatment possibilities: (1) performing an HSCT or (2) continuing treatment with the novel drug. Individual disease-specific and transplant-related risk factors, along with patient's preferences, should be taken into account when recommending one of these treatments over the other.

OSU-T315: a novel targeted therapeutic that antagonizes AKT membrane localization and activation of chronic lymphocytic leukemia cells

Aberrant regulation of endogenous survival pathways plays a major role in progression of chronic lymphocytic leukemia (CLL). Signaling via conjugation of surface receptors within the tumor environmental niche activates survival and proliferation pathways in CLL. Of these, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway appears to be pivotal to support CLL pathogenesis, and pharmacologic inhibitors targeting this axis have shown clinical activity. Here we investigate OSU-T315, a compound that disrupts the PI3K/AKT pathway in a novel manner. Dose-dependent selective cytotoxicity by OSU-T315 is noted in both CLL-derived cell lines and primary CLL cells relative to normal lymphocytes. In contrast to the highly successful Bruton's tyrosine kinase and PI3K inhibitors that inhibit B-cell receptor (BCR) signaling pathway at proximal kinases, OSU-T315 directly abrogates AKT activation by preventing translocation of AKT into lipid rafts without altering the activation of receptor-associated kinases. Through this mechanism, the agent triggers caspase-dependent apoptosis in CLL by suppressing BCR, CD49d, CD40, and Toll-like receptor 9-mediated AKT activation in an integrin-linked kinase-independent manner. In vivo, OSU-T315 attains pharmacologically active drug levels and significantly prolongs survival in the TCL1 mouse model. Together, our findings indicate a novel mechanism of action of OSU-T315 with potential therapeutic application in CLL.

New strategies in chronic lymphocytic leukemia: shifting treatment paradigms

Over the past two decades, slow but deliberate progress has been made in understanding the genetics of chronic lymphocytic leukemia (CLL) and how the surrounding microenvironment influences leukemia cell survival. The complexity of CLL with respect to different chromosomal aberrations, lack of a common aberrant signaling pathway activation, and associated immune suppression of the disease has been seen a major stumbling block for developing a single targeted therapy similar to imatinib used in chronic myeloid leukemia. The upcoming therapeutic era we are entering with the B-cell receptor (BCR) tyrosine kinase inhibitors ibrutinib and idelalisib appears to be overcoming this obstacle. Indeed, for the large majority of patients, it appears that application of BCR kinase inhibitors can promote durable remissions without the need for chemotherapy. Where other very active targeted agents such as ABT-199, therapeutic antibodies, and chimeric antigen receptor-modified T-cells will be used in CLL also represents a major question that future clinical trials will answer.

Role of allogeneic transplantation in patients with chronic lymphocytic leukemia in the era of novel therapies: a review

Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia and is characterized by a highly variable clinical course. In the past decade, several prognostic risk factors have been identified facilitating the classification of CLL into various risk groups. Patients with poor risk disease, such as poor cytogenetics or relapsing after purine-based analogues, had limited therapeutic options, with allogeneic hematopoietic cell transplantation (allo-SCT) the only known therapy with curative potential. More recently, the introduction of novel agents inhibiting the B-cell receptor pathway, and the early success with chimeric antigen receptor T cells offers an effective and relatively safe option for this poor prognostic group which holds promise in the future. Alternatively, the use of reduced intensity conditioning regimens in the allo-SCT setting has led to a significant decrease in nonrelapse mortality to 16-23%, making it an attractive therapeutic option. No recent guidelines have been developed since these novel therapies became available regarding the optimal time to allo-SCT in this patient population. The advent of these novel and highly active therapeutic agents, therefore, warrants a reappraisal of the role and timing of allo-SCT in patients with CLL. In this article, we summarize the literature regarding the novel therapeutic agents available today as well as focus on the efficacy and safety of allo-SCT.

Safety and activity of ibrutinib plus rituximab for patients with high-risk chronic lymphocytic leukaemia: a single-arm, phase 2 study

BACKGROUND

Ibrutinib, an orally administered covalent inhibitor of Bruton's tyrosine kinase (BTK), is an effective treatment for relapsed chronic lymphocytic leukaemia (CLL). We investigated the activity and safety of the combination of ibrutinib with the monoclonal antibody rituximab in patients with high-risk CLL.

METHODS

In this single-arm phase 2 study, we enrolled adult patients with high-risk CLL at the MD Anderson Cancer Center (Houston, TX, USA). All enrolled participants had high-risk cytogenetic abnormalities (deletion 17p, TP53 mutation, or deletion 11q) or a short progression-free survival (PFS <36 months) after previous first-line chemoimmunotherapy. Patients with symptomatic disease requiring therapy received 28-day cycles of once-daily ibrutinib 420 mg together with rituximab (375 mg/m(2), intravenously, every week during cycle 1, then once per cycle until cycle 6), followed by continuous daily single-agent ibrutinib 420 mg until disease progression or until toxicities or complications precluded further treatment. The primary endpoint was progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov number NCT01520519, and is no longer accruing patients.

FINDINGS

Between Feb 28, 2012, and Sept 11, 2012, we enrolled 40 patients with CLL with high-risk disease features, 20 of whom had deletion 17p (del[17p]) or TP53 mutations (16 previously treated, four untreated), 13 had relapsed CLL with deletion 11q (del[11q]), and seven a PFS less than 36 months after first-line chemoimmunotherapy. 18-month PFS in all patients was 78·0% (95% CI 60·6-88·5), whereas in those with a del(17p) or TP53 mutation it was 72·4% (45·6-87·6) Toxicity was mainly mild to moderate in severity (grade 1-2). Diarrhoea occurred in ten (25%) patients (grade 1 in nine patients and grade 2 in one), bleeding events in 14 (33%) patients (eight grade 1 and five grade 2), nausea or vomiting in 15 patients (38%) (ten grade 1 and five grade 2), and fatigue in seven (18%) patients (four grade 1 and three grade 2). Five patients (13%) had grade 3 infections (two lung infections, one upper respiratory tract infection, one sepsis, and one mucositis), and no grade 4 or 5 infections occurred. One patient had grade 4 neutropenia.

INTERPRETATION

The encouraging safety and activity of ibrutinib and rituximab in this population of patients with high-risk CLL merits further investigation of this combination.

FUNDING

Pharmacyclics Inc, Cancer Prevention and Research Institute of Texas, Leukemia and Lymphoma Society, National Cancer Institute, MD Anderson Cancer Center.

A new hope: novel therapeutic approaches to treatment of chronic lymphocytic leukaemia with defects in TP53

Chronic lymphocytic leukaemia (CLL) is an indolent B-cell malignancy with heterogeneous outcomes. Chromosomal abnormalities in CLL are predictive of the natural disease course; del(11q) and del(17p) are recognized as high risk genetic lesions. Del(17p) is associated with an impaired function of TP53, a key tumour suppressor, and is particularly problematic. Such patients respond poorly to chemo-immunotherapy and have significantly shorter survival compared to patients with standard and low-risk cytogenetics. While TP53 pathway defects are rare at initial diagnosis, their frequency increases in relapsed CLL. Until very recently, this group of patients represented an unmet clinical need with few therapeutic options. However, the advent of targeted therapies has expanded the drug armamentarium and introduced new hope for these highly refractory patients. Agents that target B-cell receptor signalling, BH3-mimetics and others induce apoptosis of the neoplastic B-cells in a TP53-independent manner. Their use in the clinic is associated with remarkable activity in patients with del(17p). In this review we discuss the frequency and clinical significance of del(17p) and genetic mutations leading to disrupted TP53, the putative role of other TP53 homologues, and the results of key clinical trials involving both conventional chemotherapy and novel agents.