Rituximab plus fludarabine and cyclophosphamide or other agents in chronic lymphocytic leukemia

Complement System: a Neglected Pathway in Immunotherapy

Approved for the treatment of autoimmune diseases, hematological malignancies, and solid cancers, several monoclonal antibodies (mAb) make use of complement in their mechanism of action. Such an assessment is based on comprehensive investigations that used mouse models, in vitro studies, and analyses from patients at initiation (basal level to highlight deficiencies) and after treatment initiation (mAb impact on complement), which have further provided key insights into the importance of the complement activation and/or complement deficiencies in mAb activity. Accordingly, new approaches can now be developed with the final objective of increasing the clinical efficacy of mAb. These improvements include (i) the concurrent administration of fresh frozen plasma during mAb therapy; (ii) mAb modifications such as immunoglobulin G subclass switching, Fc mutation, or IgG hexamerization to improve the fixation and activation of C1q; (iii) optimization of the target recognition to induce a higher complement-dependent cytotoxicity (CDC) and/or complement-dependant cellular cytotoxicity (CDCC); and (iv) the control of soluble and cellular complement inhibitors.

Resistance to complement activation, cell membrane hypersialylation and relapses in chronic lymphocytic leukemia patients treated with rituximab and chemotherapy

The anti-CD20-specific monoclonal antibody rituximab (RTX), in combination with chemotherapy, is commonly used for primary treatment in chronic lymphocytic leukemia (CLL). However, relapses remain important and activation of the complement pathway is one of the mechanisms by which RTX generates the destruction of B cells directly by complement-dependent cytotoxicity (CDC), or indirectly by antibody-dependent cellular phagocytosis. In this study, the RTX capacity to induce CDC was established in 69 untreated CLL patients, this cohort including 34 patients tested before the initiation of RTX-chemotherapy. In vitro CDC-resistance to RTX predicts lower response rates to RTX-chemotherapy and shorter treatment free survival. Furthermore, the predictive value of CDC-resistance was independent from the clinical, cytogenetic and FcγR3A V158F polymorphism status. In contrast, CLL cell resistance to CDC predominates in IGHV unmutated patients and was related to an important α2-6 sialyl transferase activity, which in turn increases cell surface α2-6 hypersialylation. Suspected factors associated with resistance to CDC (CD20, CD55, CD59, factor H, GM1, and sphingomyelin) were not differentially expressed or recruited between the two CLL groups. Altogether, results provide evidence that testing RTX capacity to induce CDC in vitro represents an independent predictive factor of therapeutic effects of RTX, and that α2-6 hypersialylation in CLL cells controls RTX response through the control of the complement pathway. At a time when CLL therapy is moving towards chemo-free treatments, further experiments are required to determine whether performing an initial in vitro assay to appreciate CLL CDC resistance might be useful to select patients.

Chronic Lymphocytic Leukemia: A Review of Front-line Treatment Options, With a Focus on Elderly CLL Patients

Chronic lymphocytic leukemia (CLL) remains the most prevalent form of leukemia in the Western world, with no cure to date. Ongoing and essential research into this heterogeneous disease has led to a number of new treatment options becoming available to CLL patients in the past decade. The present review presents the recent developments in the field of CLL treatment, with the main focus on elderly patients and CLL patients with coexisting comorbidities. The review discusses the current treatment regimens that provide the most promising outcomes for patients in this subgroup, with a number of important clinical trials summarized. These clinical trials, which have investigated promising single-agent therapies or combination therapies, are discussed, with an emphasis on the efficacy and tolerability for patients aged ≥ 65 years. Also, the misrepresentation of the true CLL population in many clinical trials and the need for better guidelines for participant inclusion criteria to provide a more realistic and accurate study population are noted.

Immune regulation effect of lienal polypeptides extract in Lewis lung carcinoma-bearing mice treated with cyclophosphamide

Polypeptides extracted from animal immune organs have been proved to exert immunomodulatory activities in previous reports. However, relative experimental data regarding the influence of a polypeptide mixture extracted from healthy calf spleen (lienal polypeptide [LP]) on the immune function in tumor therapy are limited, and the components in LP remain unclear. In the present study, the immune regulatory effect of LP was investigated in normal mice and Lewis lung carcinoma (LLC)-bearing mice treated with cyclophosphamide (CTX). The components of LP were identified by liquid chromatography-electrospray ionization-coupled with tandem mass spectrometry (LC-MS/MS) analysis and bioinformatic analysis. In LLC-bearing mice, LP showed a synergic antitumor effect with CTX, whereas LP alone did not present direct antitumor activity. Further, LP was found to enhance immune organ indexes, splenocyte number, and T lymphocyte subsets in normal mice and LLC-bearing mice treated with CTX. The decline of white blood cell and platelet counts, splenocyte proliferation activity, and peritoneal macrophage phagocytic function caused by CTX were also significantly suppressed by LP treatment in LLC-bearing mice. Notably, LP treatment significantly decreased the expression of phagocytosis-related proteins including CD47/signal regulatory protein α/Src homology phosphatase-1 in the tumor tissue of LLC-bearing mice treated with CTX. LC-MS/MS-based peptidomics unraveled the main polypeptides in LP with a length from 8 to 25 amino acids. Bioinformatics analysis further confirmed the possibility of LP to regulate immunity, especially in phagocytosis-related pathway. Our above findings indicated that LP can relieve the immunosuppression induced by chemotherapy and is a beneficial supplement in cancer therapy. Impact statement The immunomodulatory activities of polypeptides extracted from animal immune organs have incurred people's interests since a long time ago. In this study, we investigated the immune regulation effects of a polypeptide mixture extracted from health calf spleen (lienal polypeptide [LP]) in Lewis lung carcinoma-bearing mice treated with cyclophosphamide (CTX). Liquid chromatography-electrospray ionization-coupled with tandem mass spectrometry-based peptidomics and bioinformatics analysis unraveled the main polypeptides in LP and further confirmed that LP is mainly associated with immune regulating pathway, especially in tumor cell phagocytosis-related pathway. Our study for the first time revealed that polypeptides from spleen can relieve the immunosuppression induced by CTX and is a beneficial supplement in cancer therapy.

Current and emerging monoclonal antibody treatments for chronic lymphocytic leukemia: state of the art

Anti-CD20 monoclonal antibodies (mAbs), rituximab, ofatumumab and obinutuzumab, have a significant impact in the treatment of chronic lymphocytic leukemia (CLL), particularly in combination with chemotherapy. Over the last few years, several new mAbs have been developed and investigated in CLL. The most promising newer mAbs are directed against CD20, CD19, CD37 and CD40. Combinations of antibodies with targeted drugs like ibrutinib, idelalisib or lenalidomide will probably replace chemotherapy-based combinations in the near future. This review gives a critical overview of established mAbs as well as new antibodies potentially useful in CLL.

[Chronic lymphocytic leukemia accompanied by renal failure]

AIM

To evaluate the efficiency and safety of monotherapy with bendamustine (B) and therapy with B in combination with rituximab (B + R) in patients with chronic lymphocytic leukemia (CLL) accompanied by renal failure (RF).

SUBJECTS AND METHODS

The prospective pilot study included 8 patients (6 men, 2 women) with CLL concurrent with RF. The patients' median age was 63 years (51-77 years). The Binet classification stage of CLL corresponded to B in 2 cases and C in 6. The mean (± standard error) pretreatment concentration of creatinine was 218 ± 92 μmol/l and the glomerular filtration rate (GFR) was 33 ± 20 ml/min. The efficiency of monotherapy with B (n=5) and combination therapy with B + R (n=3) was evaluated. In progressive CLL, therapy was performed in specific treatment-naïve patients (n = 5) and in pretreated patients refractory to alkylating agents (cyclophosphan, chlorambucil) (n = 3). A total of cycles of B and B + R were carried out.

RESULTS

After B monotherapy, one of the 5 cases achieved a complete remission, 3 a partial remission, and 1 a nodular partial remission. Three patients developed recurrence. In the B monotherapy group, the cumulative risk of recurrence was 70% at a median follow-up of 22 months and at a maximum follow-up of 27 months. In the B + R therapy group, all the 3 patients achieved a complete remission. The median follow-up was 7 months; the maximum follow-up was 1 year. There were no deaths or recurrences. During B monotherapy and B + R combination therapy, there was improved kidney function: the mean concentration of creatinine decreased from 218 ± 92 to 140 ± 57 μmol/l (p < 0.05); GFR increased from 33 ± 20.0 to 54 ± 25 ml/min; the mean increment was 20 ml/min (p < 0.01). Mild and moderate anemia and thrombocytopenia were most common during B and B + R therapies. Neutropenia with mild infection complications, as well as nonhematologic complications were detected in some cases. The drugs were observed to have no nephrotoxic effects.

CONCLUSION

The performed pilot prospective indicated that the B + R combination therapy was effective in patients with RF-associated CLL. No toxic effect of B on kidney function was seen. During B therapy, there was better kidney function manifesting itself as a statistically and clinically important decrease in creatinine concentrations and a statistically and clinically important increase in GFR as compared to the baseline values.

A phase II study of a nonmyeloablative allogeneic stem cell transplant with peritransplant rituximab in patients with B cell lymphoid malignancies: favorably durable event-free survival in chemosensitive patients

The aim of this prospective phase II trial was to determine the safety and efficacy of a nonmyeloablative conditioning program incorporating peritransplant rituximab in patients with CD20+ B cell non-Hodgkin lymphoma (B-NHL) receiving an allogeneic stem cell transplant (allo-SCT). Fifty-one adult B-NHL patients, with a median age of 54 years, were treated with cyclophosphamide, fludarabine, and 200 cGy of total body irradiation. Rituximab 375 mg/m(2) was given on day -8 and in 4 weekly doses beginning day +21. Equine antithymocyte globulin was given to recipients of volunteer unrelated donor grafts. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and mycophenolate mofetil and tacrolimus, sirolimus, and methotrexate in 8 and 43 patients, respectively. Thirty-three patients received grafts from unrelated donors, and 18 received grafts from matched related donors. All patients engrafted. Full donor chimerism in bone marrow and peripheral T cells was seen in 92% and 89% of patients, respectively, at 3 months after allo-SCT. The cumulative incidence of grades II to IV acute GVHD at 6 months was 25% (95% confidence interval [CI], 13% to 38%) and grades III to IV was 11% (95% CI, 2% to 20%). The 2-year cumulative incidence of chronic GVHD was 29% (95% CI, 15% to 44%). The 2-year event-free and overall survival for all patients was 72% (95% CI, 59% to 85%) and 78% (95% CI, 66% to 90%), respectively. The 2-year event-free survival for chemosensitive patients was 84% (95% CI, 72% to 96%) compared with 30% (95% CI, 2% to 58%) for chemorefractory patients before allo-SCT (P < .001). This nonmyeloablative regimen, with peritransplant rituximab, is safe and effective in patients with B-NHL.

Demographics, treatment patterns, safety, and real-world effectiveness in patients aged 70 years and over with chronic lymphocytic leukemia receiving bendamustine with or without rituximab: a retrospective study

OBJECTIVES

Bendamustine is a unique cytotoxic agent active against various human malignancies, including chronic lymphocytic leukemia (CLL). In vitro studies suggest that cytotoxic activity of bendamustine on CLL-derived cells is synergized by rituximab. A retrospective chart review was conducted to characterize treatment-naïve outpatients and those with relapsed disease aged 70 years and over with CLL receiving bendamustine (with or without rituximab) and to evaluate real-world patterns of care, safety, and effectiveness.

METHODS

Using McKesson Specialty Care/US Oncology Network iKnowMed databases, 91 outpatients with at least two recorded visits and at least two cycles of bendamustine monotherapy or bendamustine-rituximab combination therapy were identified and included. Mean age at diagnosis and start of first therapy was 70.3 and 77.4 years respectively, and 63.7% of patients were men.

RESULTS

Observed overall response rate was 56.3% in pooled treatment-naïve patients [n = 9; complete response (CR) 18.8%; partial response (PR) 37.5%; nodular partial response (nPR) 0%] and 58.7% in pooled patients with relapsed disease (n = 44; CR 13.3%; PR 44.0%; nPR 1.3%). Median time to progressive disease has not been reached for the 16 treatment-naïve patients (median follow up 15.1 months), and was 18.4 months for those with relapsed disease (n = 73). No unexpected toxicities were observed. Overall rate of blood/bone marrow toxicities (all grades) was 40.7%; grade 3/4 rates were 18.8% in treatment-naïve patients and 25.3% in those with relapsed disease. Most frequent nonhematologic adverse events were fatigue and rash.

CONCLUSION

In this retrospective chart review of 91 outpatients with CLL aged 70 years and over, bendamustine (with or without rituximab) was an effective therapeutic option with manageable toxicity.

Beneficial effects of 20(S)-protopanaxadiol on antitumor activity and toxicity of cyclophosphamide in tumor-bearing mice

20(S)-protopanaxadiol (PPD) is an extract of Panax quinquefolius L. The aim of this study was to investigate the effect of PPD on the antitumor activity and toxicity of cyclophosphamide (CTX) in tumor-bearing mice. C57BL/6 mice bearing Lewis lung carcinoma cells were treated with PPD (50 mg/kg) alone, CTX (20 mg/kg) alone or PPD (50 mg/kg) in combination with CTX (20 mg/kg), respectively. The results showed that PPD alone has no significant antitumor activity but synergistically enhanced the antitumor activity of CTX. PPD significantly increased the peripheral white blood cell count, bone marrow cell count, interleukin-2 and interferon-γ in CTX-treated tumor-bearing mice. The lowered levels of spleen index, splenocyte proliferation and natural killer cell activity in tumor-bearing mice following CTX treatment were also increased by PPD administration. PPD may be a beneficial supplement during CTX chemotherapy for enhancing the antitumor efficacy and reducing the toxicity of CTX.

Comparison on therapeutic effects of RFT and RCTVP regimen in the treatment of patients with indolent B-cell lymphoma in China

To compare the efficacy and safety of RFT (retuximab, fludarabine, pirarubicin) with RCTVP (retuximab, cyclophophamide, pirarubicin, vindesine and prednisone) in 248 indolent B-cell non-Hodgkin's lymphoma (NHL) patients. Two hundred and forty-eight patients with indolent B-cell NHL were treated with combined chemotherapy, including RFT and RCTVP, from January 2002 to December 2010 in Tianjin Cancer Hospital. The rate of response, toxicity and long-term survival for the two regimens were analyzed retrospectively. For the previously untreated patients, overall response rate for RFT arm and RCTVP arm was 71.7 and 70.6%, and complete response rate was 47.5 and 54.9%, respectively (P>0.05). For the refractory and relapsed patients, overall response (OR) rate and complete response (CR) rate were significantly improved in the RFT arm versus the RCTVP arm (P<0.05). There were no statistically significant differences in overall survival (OS) between treatment groups. Comparing with RCTVP regimen, fludarabine-based treatment was associated with superior PFS both in previously untreated, refractory and relapsed patients. WHO grades 3 and 4 hematological adverse events were more common in the RFT arm. Neurotoxicity was more common in the RCTVP arm. For the previously untreated patients, there was no difference between RFT arm and RCTVP arm on OR and CR rates. For the refractory and relapsed indolent B-cell NHL patients who received RFT regimen achieved higher OR and CR rates compared with RCTVP-treated patients. No differences in OS were noted. RFT regimen was associated with superior PFS both in previously untreated, refractory and relapsed patients. RFT regimen is effective and well tolerated for patients with untreated, refractory and relapsed indolent B-cell NHL.

[Antimetabolites]

Antimetabolites are cytotoxic agents, which have been developed for more than 50  years. Which cancer patient did not receive or will not receive 5-fluorouracil or methotrexate during the evolution his or her disease? Antimetabolites are defined as interfering with the synthesis of the DNA constituents; they are structural analogues, either of purine and pyrimidine bases (or the corresponding nucleosides), or of folate cofactors, which are involved at several steps of purine and pyrimidine biosynthesis. Their first mechanism of action is, therefore, to induce depletion in nucleotides inducing in turn an inhibition of DNA replication. However, some of them are able to get inserted fraudulently into nucleic acids, inducing structural abnormalities leading to cell death by other mechanisms, including DNA breaks. We present in this paper, for the three classes of antimetabolites, both ancient and recent molecules as well as molecules still in clinical trials, without exhaustivity.

Polymorphisms and haplotypes in multidrug resistance 1 gene are not associated with chronic lymphocytic leukemia susceptibility and prognostic parameters of chronic lymphocytic leukemia in Chinese population

The human multidrug resistance (MDR1, ABCB1) gene encodes P-glycoprotein (P-gp), which affects the pharmacokinetics of many drugs. Here, we investigated whether common MDR1 single nucleotide polymorphisms (SNPs) (C1236T, C3435T, and G2677T/A) affect predisposition to chronic lymphocytic leukemia (CLL). Genotyping was performed in 150 patients with CLL and 117 controls using polymerase chain reaction (PCR)-based assays. Haplotypes were inferred using the PHASE algorithm. We found comparable allele and genotype frequencies among patients with CLL and controls. Moreover, patient and control groups did not differ regarding MDR1 haplotype distribution (p = 0.97). Furthermore, no correlation was shown between the MDR1 1236, 3435, or 2677 genotypes and Binet stage, unmutated immunoglobulin heavy-chain variable region (IGHV) status, CD38 expression, ZAP-70 expression, and p53 deletion. In conclusion, our results do not support a major influence of MDR1 variants on the risk of CLL, and these genomic polymorphisms are not associated with clinical prognostic factors in Chinese patients with CLL.