The combination of rituximab, bendamustine, and cytarabine for heavily pretreated relapsed/refractory cytogenetically high-risk patients with chronic lymphocytic leukemia

Secondary Immunodeficiency in Hematological Malignancies: Focus on Multiple Myeloma and Chronic Lymphocytic Leukemia

Secondary immunodeficiency is reported in most patients with hematological malignancies such as chronic lymphocytic leukemia and multiple myeloma. The aim of our review was to evaluate the existing literature data on patients with hematological malignancies, with regard to the effect of immunodeficiency on the outcome, the clinical and therapeutic approach, and on the onset of noninfectious complications, including thrombosis, pleural effusion, and orofacial complications. Immunodeficiency in these patients has an intense impact on their risk of infection, in turn increasing morbidity and mortality even years after treatment completion. However, these patients with increased risk of severe infectious diseases could be treated with adequate vaccination coverage, but the vaccines' administration can be associated with a decreased immune response and an augmented risk of adverse reactions. Probably, immunogenicity of the inactivated is analogous to that of healthy subjects at the moment of vaccination, but it undertakes a gradual weakening over time. However, the dispensation of live attenuated viral vaccines is controversial because of the risk of the activation of vaccine viruses. A particular immunization schedule should be employed according to the clinical and immunological condition of each of these patients to guarantee a constant immune response without any risks to the patients' health.

Nitrogen Mustards as Anticancer Chemotherapies: Historic Perspective, Current Developments and Future Trends

Nitrogen mustards, a family of DNA alkylating agents, marked the start of cancer pharmacotherapy. While traditionally characterized by their dose-limiting toxic effects, nitrogen mustards have been the subject of intense research efforts, which have led to safer and more effective agents. Even though the alkylating prodrug mustards were first developed decades ago, active research on ways to improve their selectivity and cytotoxic efficacy is a currently active topic of research. This review addresses the historical development of the nitrogen mustards, outlining their mechanism of action, and discussing the improvements on their therapeutic profile made through rational structure modifications. A special emphasis is made on discussing the nitrogen mustard prodrug category, with Cyclophosphamide (CPA) serving as the main highlight. Selected insights on the latest developments on nitrogen mustards are then provided, limiting such information to agents that preserve the original nitrogen mustard mechanism as their primary mode of action. Additionally, future trends that might follow in the quest to optimize these invaluable chemotherapeutic medications are succinctly suggested.

Olaptesed pegol (NOX-A12) with bendamustine and rituximab: a phase IIa study in patients with relapsed/refractory chronic lymphocytic leukemia

Olaptesed pegol (NOX-A12) is a pegylated structured L-oligoribonucleotide that binds and neutralizes CXCL12, a chemokine tightly regulating the life cycle of chronic lymphocytic leukemia cells. The resulting inhibition of CXCR4 and CXCR7 signaling reduces the protective activity of the bone marrow and lymph node microenvironment. CXCL12 inhibition mobilizes chronic lymphocytic leukemia cells into the circulation and prevents their homing into the protective niches. In this phase I/II study, 28 patients with relapsed/refractory chronic lymphocytic leukemia were treated with olaptesed pegol in combination with bendamustine and rituximab. Combination treatment was preceded by single escalating pilot doses of olaptesed pegol in the first ten patients for evaluation of safety and pharmacokinetics. Peak concentrations and systemic exposure of olaptesed pegol were dose-linear; plasma elimination was monophasic with a 53.2 h half-life. A rapid increase in circulating chronic lymphocytic leukemia cells was observed already 1 h after administration of olaptesed pegol and lasted for at least 72 h. Single-agent treatment was well tolerated and no dose-limiting toxicity was observed. The combination regimen yielded an overall response rate of 86%, with 11% of patients achieving a complete response and 75% a partial response. Notably, all ten high-risk patients, including four with a 17p deletion, responded to treatment. The median progression-free survival was 15.4 (95% confidence interval: 12.2, 26.2) months while the median overall survival was not reached with >80% of patients alive after a median follow-up of 28 months. Olaptesed pegol was well tolerated and did not result in additional toxicity when combined with bendamustine and rituximab (ClinicalTrials.gov identifier: NCT01486797). Further clinical development of this novel CXCL12 inhibitor is thus warranted.

Treatment of Del17p and/or aberrant TP53 chronic lymphocytic leukemia in the era of novel therapies

More effective therapies are emerging, with better toxicity profiles, and are being incorporated into modern treatment algorithms of chronic lymphocytic leukemia at various stages of the disease, including for patients harboring Del17p and/or aberrant TP53. Ibrutinib, an inhibitor of Bruton's tyrosine kinase, has demonstrated impressive response rates in the relapsed/refractory setting, including in the setting of Del17p and/or TP53 mutations. Venetoclax, an inhibitor of BCL-2 known to play an important role in regulating cell death, has been approved recently for treatment of patients with chronic lymphocytic leukemia with Del17p who have received at least one prior therapy. Unfortunately, a cure remains unattainable unless eligible patients are offered an allogeneic hematopoietic cell transplant. However, hematopoietic cell allografting is limited by the availability of suitable donors and significant morbidity and mortality. Recent clinical practice recommendations by the American Society for Blood and Marrow Transplantation have relegated the role of transplantation to later stages of the disease. In patients with evidence of Richter syndrome, frontline consolidation allogeneic hematopoietic cell transplantation remains the most desirable approach owing to the limited activity of ibrutinib or other novel therapies. Further therapeutic advances would require enrolling these patients in large clinical trials that evaluate novel therapies alone or in combination with traditional chemotherapies or even in the setting of posttransplant consolidation/maintenance.

Bendamustine and its role in the treatment of unfit patients with chronic lymphocytic leukaemia: a perspective review

With a median age of 72 years at first diagnosis, chronic lymphocytic leukaemia (CLL) is a disease of the elderly. At this age, many patients cannot bear an intensive chemoimmunotherapy like fludarabine, cyclophosphamide and rituximab (FCR), and therapeutic decisions are commonly complicated by a high burden of accompanying comorbidities. Clinical trials, on the other hand, are mostly designed to include a far healthier and younger trial population, with a median age in most studies well below 70 years, leading to an insufficient reflection of clinical reality. With the introduction of new targeted therapies, treatment of CLL is currently undergoing a profound change. New compounds like ibrutinib or idelalisib have enlarged the therapeutic options in treating CLL. However, so far, these oral medications imply continuous intake by the patient, which will at some point lead to the issue of adherence in most patients. In addition, long-term experiences are largely missing. In this setting, one of the oldest chemoactive substances remains a viable option for many CLL patients and their treating physicians: bendamustine, a nitrogen-mustard derivative, has proven to be a safe and efficient agent for treatment of CLL in the first- and second-line setting. In particular, there is some evidence that the substance is relatively well tolerated in elderly and unfit patients. In this review, we summarize the current data on bendamustine in the treatment of elderly and unfit patients with CLL and aim to provide a concise analysis and outlook on the current and future role of this substance in the era of new targeted agents.

Challenges in the Role of Gammaglobulin Replacement Therapy and Vaccination Strategies for Hematological Malignancy

Patients with chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are prone to present with antibody production deficits associated with recurrent or severe bacterial infections that might benefit from human immunoglobulin (Ig) (IVIg/SCIg) replacement therapy. However, the original IVIg trial data were done before modern therapies were available, and the current indications do not take into account the shift in the immune situation of current treatment combinations and changes in the spectrum of infections. Besides, patients affected by other B cell malignancies present with similar immunodeficiency and manifestations while they are not covered by the current IVIg indications. A potential beneficial strategy could be to vaccinate patients at monoclonal B lymphocytosis and monoclonal gammopathy of undetermined significance stages (for CLL and MM, respectively) or at B-cell malignancy diagnosis, when better antibody responses are attained. We have to re-emphasize the need for assessing and monitoring specific antibody responses; these are warranted to select adequately those patients for whom early intervention with prophylactic anti-infective therapy and/or IVIg is preferred. This review provides an overview of the current scenario, with a focus on prevention of infection in patients with hematological malignancies and the role of Ig replacement therapy.

Ibrutinib: a paradigm shift in management of CLL

B-cell receptor (BCR) signaling plays a vital role in B-cell malignancies; Bruton tyrosine kinase is a critical mediator of this signaling. BCR signaling, either constitutively or following antigen binding, leads to activation of several downstream pathways involved in cell survival, proliferation and migration. The efficacy observed in studies of the Bruton tyrosine kinase inhibitor, ibrutinib, confirms that BCR signaling is critical for the growth of B-cell malignancies. Ibrutinib characteristically induces redistribution of malignant B cells from tissues into the peripheral blood and rapid resolution of adenopathy. Furthermore, ibrutinib therapy results in normalization of lymphocyte counts and improvement in cytopenias. Ibrutinib has been shown to have an excellent safety profile and does not cause myelosuppression. Early data from combination studies of ibrutinib with anti-CD20 monoclonal antibodies have shown more rapid responses compared to those seen with ibrutinib monotherapy. Current data strongly support continued clinical evaluation of ibrutinib in B-cell malignancies.

Clinical activity of a new regimen combining gemcitabine and alemtuzumab in high-risk relapsed/refractory chronic lymphocytic leukemia patients

Optimal treatment strategies are lacking in relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). Gemcitabine has shown activity and acceptable safety profile in B-cell lymphomas. We present a retrospective case review of gemcitabine and alemtuzumab, every 21 d (for up to six courses) in 27 community-based patients with high-risk R/R CLL. Median age was 70 yr (44-83 yr), 55% patients had Binet stage C, deletion 17p (del(17p)) and/or deletion 11q (del(11q)) were found in 65% and 27%, bulky disease in 55.5%, and fludarabine-refractoriness in 48% of cases, respectively. Overall response rate was 63% (29.6% clinical CR and 33.4% PR). At a median follow-up of 31 months, median PFS and OS were 15.4 and 24 months. In multivariate analysis, median OS is influenced by prior lines of treatment = 3 and bulky disease. Combination of alemtuzumab and gemcitabine appears to be an active, easy to administrate treatment in routine practice, high-risk R/R CLL patients.

Modern treatment in chronic lymphocytic leukemia: impact on survival and efficacy in high-risk subgroups

Treatment of chronic lymphocytic leukemia (CLL) has dramatically changed over the last years, with significant improvement in overall survival (OS) and increased efficacy in genetically defined "high-risk" disease. Besides prospective clinical trials usually enrolling young and fit patients, retrospective studies were performed comparing the outcome of patients belonging to different age groups and showing longer survival in patients diagnosed in the most recent periods. In patients younger than 70 years the 10-year relative survival was 43-53% in the 1980s as compared with 59-63% in the 2000s. Likewise, the 10-year relative survival in patients >70 years was 22-42% in the 1980s and 46-55% in the 2000s. Improved outcome derived in part by the introduction of effective regimens in genetically defined "high-risk" disease (i.e., 17p-, 11q-, TP53, NOTCH1, SF3B1 mutations), especially in the younger and/or fit patients. The unfavorable prognostic significance of 11q- was overcome by chemoimmunotherapy. High-dose steroids with anti-CD52 appeared to improve the response rate in 17p-/TP53 mutated cases and allogeneic transplantation achieved prolonged disease control irrespective of high-risk disease. Further improvement is being generated by the new anti-CD20 obinutuzumab in the elderly and by mechanism-based treatment using kinase-targeting agents or anti-BCL2 molecules yielding high-response rate and impressive progression-free survival in the chemorefractory setting as well as in previously untreated patients.

Purine analog-like properties of bendamustine underlie rapid activation of DNA damage response and synergistic effects with pyrimidine analogues in lymphoid malignancies

Bendamustine has shown considerable clinical activity against indolent lymphoid malignancies as a single agent or in combination with rituximab, but combination with additional anti-cancer drugs may be required for refractory and/or relapsed cases as well as other intractable tumors. In this study, we attempted to determine suitable anti-cancer drugs to be combined with bendamustine for the treatment of mantle cell lymphoma, diffuse large B-cell lymphoma, aggressive lymphomas and multiple myeloma, all of which are relatively resistant to this drug, and investigated the mechanisms underlying synergism. Isobologram analysis revealed that bendamustine had synergistic effects with alkylating agents (4-hydroperoxy-cyclophosphamide, chlorambucil and melphalan) and pyrimidine analogues (cytosine arabinoside, gemcitabine and decitabine) in HBL-2, B104, Namalwa and U266 cell lines, which represent the above entities respectively. In cell cycle analysis, bendamustine induced late S-phase arrest, which was enhanced by 4-hydroperoxy-cyclophosphamide, and potentiated early S-phase arrest by cytosine arabinoside (Ara-C), followed by a robust increase in the size of sub-G1 fractions. Bendamustine was able to elicit DNA damage response and subsequent apoptosis faster and with shorter exposure than other alkylating agents due to rapid intracellular incorporation via equilibrative nucleoside transporters (ENTs). Furthermore, bendamustine increased the expression of ENT1 at both mRNA and protein levels and enhanced the uptake of Ara-C and subsequent increase in Ara-C triphosphate (Ara-CTP) in HBL-2 cells to an extent comparable with the purine analog fludarabine. These purine analog-like properties of bendamustine may underlie favorable combinations with other alkylators and pyrimidine analogues. Our findings may provide a theoretical basis for the development of more effective bendamustine-based combination therapies.

Bendamustine in chronic lymphocytic leukemia: outcome according to different clinical and biological prognostic factors in the everyday clinical practice

Bendamustine proved to be effective for the treatment of chronic lymphocytic leukemia (CLL). However, the relationship between its activity with clinico-biological prognosticators has been addressed only in few studies. We retrospectively evaluated the efficacy of bendamustine, in a real-life contest, on 142 patients, median age 70 years, median number of previous regimens 2 (0-8, 13% previously untreated). Bendamustine was administered for a median number of 4 cycles, in 84% of cases with rituximab. Overall (ORR) and complete response (CRR) rates were 68 and 16.5%, respectively. Multivariate analysis demonstrated a relationship between ORR and number of prior treatments (OR 0.25, 95% CI 0.08-0.71; P = 0.009), del(17p) (OR 0.10, 95% CI 0.03-0.32; P < 0.001) and concomitant rituximab (OR 4.37, 95% CI 1.12-17.04; P = 0.033). The estimated 1- and 2-years overall survival (OS) and progression free survival (PFS) rates were 76, 61, 51, and 26%, respectively. Previous sensitivity to fludarabine (HR 0.36, 95% CI 0.16-0.82), response to bendamustine (HR 0.21, 95% CI 0.10-0.45), and del(17p) (HR 2.18, 95% CI 1.002-4.74) had a prognostic significance in multivariate analysis for PFS, while the number of previous therapies (HR 3.48, 95% CI 1.29-9.38; P = 0.014), concomitant use of rituximab (HR 0.32, 95% CI 0.11-0.93) and response to bendamustine (HR 0.22, 95% CI 0.07-0.66) were significant for OS. Side effects included grade 3-4 neutropenia, infections, thrombocytopenia and anemia which occurred in 40, 14, 14, and 10% of patients, respectively. These results confirm the activity and safety of bendamustine and rituximab combination even in patients with unfavorable clinical and biological features excluding del(17p).