Phase II study of oral fludarabine in combination with rituximab for relapsed indolent B-cell non-Hodgkin lymphoma

Clinical pharmacology and clinical trials of ribonucleotide reductase inhibitors: is it a viable cancer therapy?

PURPOSE

Ribonucleotide reductase (RR) enzymes (RR1 and RR2) play an important role in the reduction of ribonucleotides to deoxyribonucleotides which is involved in DNA replication and repair. Augmented RR activity has been ascribed to uncontrolled cell growth and tumorigenic transformation.

METHODS

This review mainly focuses on several biological and chemical RR inhibitors (e.g., siRNA, GTI-2040, GTI-2501, triapine, gemcitabine, and clofarabine) that have been evaluated in clinical trials with promising anticancer activity from 1960's till 2016. A summary on whether their monotherapy or combination is still effective for further use is discussed.

RESULTS

Among the RR2 inhibitors evaluated, GTI-2040, siRNA, gallium nitrate and didox were more efficacious as a monotherapy, whereas triapine was found to be more efficacious as combination agent. Hydroxyurea is currently used more in combination therapy, even though it is efficacious as a monotherapy. Gallium nitrate showed mixed results in combination therapy, while the combination activity of didox is yet to be evaluated. RR1 inhibitors that have long been used in chemotherapy such as gemcitabine, cladribine, fludarabine and clofarabine are currently used mostly as a combination therapy, but are equally efficacious as a monotherapy, except tezacitabine which did not progress beyond phase I trials.

CONCLUSIONS

Based on the results of clinical trials, we conclude that RR inhibitors are viable treatment options, either as a monotherapy or as a combination in cancer chemotherapy. With the recent advances made in cancer biology, further development of RR inhibitors with improved efficacy and reduced toxicity is possible for treatment of variety of cancers.

Treatment of follicular lymphoma

Follicular lymphoma (FL) is the most common subtype of indolent lymphomas. Several lines of evidence suggest that the prognosis of patients with FL has improved since the introduction of rituximab, although cure cannot be achieved. Although the treatment paradigm for FL has changed over the past decade with the introduction of rituximab and other agents, there is still no standard therapy to fit all patients. Instead, treatment decisions are made taking into consideration disease status (stage, tumor burden, and presence of symptoms) and patient factors including patient preferences. Rituximab-containing chemotherapy such as R-CHOP, R-CVP, and bendamustine plus rituximab is usually recommended for symptomatic patients. However, optimal rituximab-containing chemotherapy has not been established. Rituximab maintenance is one of the post-induction options for patients responding to first-line chemoimmunotherapy. For patients without symptoms and low-tumor burden, both expectant management (watchful waiting) and rituximab monotherapy are reasonable options. A very limited proportion of patients with FL are diagnosed at stage I with rigorous staging using bone marrow biopsy and whole-body imaging with computed tomography (CT) and/or positron emission tomography/CT. Although local radiotherapy has been the standard approach for these patients, its role is being questioned. Patients with FL who achieve remission eventually relapse and require salvage therapy. The salvage regimen should be chosen taking into account previous treatment and its response duration. Moreover, the presence of histological transformation should be assessed.

Clinical and economic aspects of the use of rituximab in non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma (NHL) consists of a group of neoplasias involving mainly B cells and represents 90% of all lymphomas. The current available therapy is based on chemotherapy associated with the monoclonal antibody rituximab (Mab Thera(r)), which targets the CD20 protein, present in over 80% of NHL mature B cells. Recent clinical reports show a preference for combining the benefits of immunotherapy and adjuvant chemotherapy, thus generating safe and effective alternative treatments. The current review aimed at evaluating various aspects related to the use of rituximab for NHL, highlighting the possible inhibitory mechanisms of cell proliferation, the achieved clinical results, and the expected clinical and economic outcomes of treatments. The results from clinical tests indicate the need for a better understanding of the critical mechanisms of action of this antibody, which may maximize its therapeutic efficacy. This therapy not only represents a viable option to treat most types of NHLs, especially when associated with conventional chemotherapy, but also offers cost-utility and cost-effectiveness advantages.

Reduced-intensity allogeneic stem cell transplantation for co-emergence of chemotherapy-refractory follicular lymphoma and therapy-related myelodysplastic syndrome

A 54-year-old male was diagnosed with follicular lymphoma in September 2003. Despite multiple chemotherapies, including autologous hematopoietic stem cell transplantation (HSCT) with high-dose chemotherapy, the disease eventually relapsed. Additionally, bone marrow analysis revealed the co-emergence of therapy-related myelodysplastic syndrome (t-MDS) in February 2012. In March 2012, we performed related allogeneic HSCT for the treatment of both malignancies. This strategy was successful and the patient has remained free from both malignancies for 23 months. Allogeneic HSCT is a potent curative therapeutic option for both t-MDS and refractory follicular lymphoma.

Fludarabine-containing chemotherapy for patients with previously untreated low-grade non-Hodgkin's lymphoma

BACKGROUND

The clinical efficacy and safety of fludarabine combination chemotherapy was investigated for the treatment of previously untreated patients with low-grade (NHL).

METHODS

Twenty-five patients who were newly diagnosed as low-grade NHL were treated with fludarabine combination chemotherapy. Fludarabine combination regimens consisted of fludarabine, mitoxantrone and dexamethasone or fludarabine, cyclophosphamide and mitoxantrone with or without rituximab and repeated every 4 weeks.

RESULTS

The median age was 60 years (range, 35-77 years), with 13 of 25 patients (52%) ≥60 years of age. Seven of 25 patients (28%) with an intermediate risk follicular lymphoma international prognostic index (FLIPI) and 9 of 25 patients (36%) with a high risk FLIPI were enrolled in this study. The delivered median number of chemotherapy was six (range, 2-9 cycles). The overall response rate with fludarabine-based treatment was 88%, including 52% complete remission and 36% partial remission. During the median follow-up of 19 months, the estimated 2-year event-free survival was 63±10% (95% CI, 43-83) and the 2-year overall survival was 78±9% (95% CI, 60-96). Fludarabine combination chemotherapy was frequently associated with grade 3 or 4 neutropenia in 84% patients. However, neutropenic infection was observed in only one (4%) patient. Four patients (16%) showed grade 3 or more non-hematologic toxicities, such as acute coronary syndrome, intracranial hemorrhage, anaphylaxis and gastric cancer.

CONCLUSION

Fludarabine-combination treatment was a highly active regimen with well toleration in untreated low-grade NHL.

Cladribine combined with rituximab (R-2-CdA) therapy is an effective salvage therapy in relapsed or refractory indolent B-cell non-Hodgkin lymphoma

Although cladribine has been reported to be an active purine analog against indolent B-cell non-Hodgkin lymphoma (B-NHL), there are few reports of combination use of cladribine and rituximab. This multicenter phase II study evaluated the efficacy and toxicity of cladribine with rituximab (R-2-CdA) therapy in relapsed or refractory indolent B-NHL. Twenty patients with the median age of 58.5 yrs (range, 42-72) were enrolled and received R-2-CdA therapy from April 2005 to July 2007. The median number of prior regimens was 2 (range, 1-3), and fifteen patients (75%) were previously treated with rituximab-containing regimens. Disease histology included follicular lymphoma in 16 patients, MALT lymphoma in two patients, nodal marginal B-cell lymphoma in one patient, and lymphoplasmacytic lymphoma in one patient. The overall response rate (ORR) was 90%, with a complete response rate (CRR) of 70%. Estimated median progression-free survival (PFS) time was 22.4 months (95%CI, 10.9-32.6 months) at a median follow-up time of 27 months (range, 12-43). Two-year PFS and 2-yr overall survival (OS) were 52.6% (95%CI, 31.0-73.2%) and 89.5% (95%CI, 66.1-97.3%), respectively. Grade 3 or grade 4 toxicities were neutropenia in 74% and thrombocytopenia in 11%. R-2-CdA therapy was demonstrated to have a high activity with durable PFS and acceptable toxicity in relapsed or refractory indolent B-NHL mostly pretreated with rituximab-containing therapy. Although a large-scale trial is needed for confirmation, R-2-CdA therapy could be a good salvage therapy option in relapsed or refractory indolent B-NHL.

Relapsed or refractory nongastric marginal zone B-cell lymphoma: multicenter retrospective analysis of 92 cases

Over its long survival duration, marginal zone B-cell lymphoma (MZL) routinely involves frequent relapses. In this study, we conducted a retrospective analysis to identify the clinical features and outcomes of relapsed or refractory MZL. From 1995 to 2008, a total of 92 patients with relapsed MZL were retrospectively analyzed. The median age of our subjects was 53.5 years (range: 23-82 years). The most common primary sites of involvement were the orbit and ocular adnexa (28.3%) followed by the lymph node and lymphatic organs (23.9%), and multiple mucosa-associated lymphoid tissue (MALT) sites (13.0%). The median time to relapse from initial diagnosis was 25.5 months. Of the 53 patients with Stage I or II at diagnosis, 42 patients (79.2%) evidenced locoregional recurrence. Among these locoregional relapsed patients, 27 patients achieved CR (54.1%) or PR (18.9%). In addition to the 39 patients initially in advanced Stage III or IV, a total of 50 patients were in advanced stage at relapse. Among those patients with advanced stage at relapse, 44 patients were treated. The overall response rate was 54.5% (24 patients), with 18 CRs and 6 PRs. The median time to progression (TTP) was 34.1 months (95% CI: 11.3-56.9 months) and the estimated 5-year overall survival (OS) was 84.3%. The majority of them was controlled well with salvage treatment, and could achieve prolonged survival. However, patients' refractory to initial therapy and advanced relapse evidenced shorter TTP and OS. Thus, we need to consider more aggressive treatment in cases of refractory MZL or advanced relapsed MZL.