Fludarabine phosphate in lymphoma: an important new therapeutic agent

Marine sponge-derived/inspired drugs and their applications in drug delivery systems

Oceans harbor a vast biodiversity that is not represented in terrestrial habitats. Marine sponges have been the richest source of marine natural products reported to date, and sponge-derived natural products have served as inspiration for the development of several drugs in clinical use. However, many promising sponge-derived drug candidates have been stalled in clinical trials due to lack of efficacy, off-target toxicity, metabolic instability or poor pharmacokinetics. One possible solution to this high clinical failure rate is to design drug delivery systems that deliver drugs in a controlled and specific manner. This review critically analyzes drugs/drug candidates inspired by sponge natural products and the potential use of drug delivery systems as a new strategy to enhance the success rate for translation into clinical use.

Trabectedin Reveals a Strategy of Immunomodulation in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a B-cell neoplasia characterized by protumor immune dysregulation involving nonmalignant cells of the microenvironment, including T lymphocytes and tumor-associated myeloid cells. Although therapeutic agents have improved treatment options for CLL, many patients still fail to respond. Some patients also show immunosuppression. We have investigated trabectedin, a marine-derived compound with cytotoxic activity on macrophages in solid tumors. Here, we demonstrate that trabectedin induces apoptosis of human primary leukemic cells and also selected myeloid and lymphoid immunosuppressive cells, mainly through the TRAIL/TNF pathway. Trabectedin modulates transcription and translation of IL6, CCL2, and IFNα in myeloid cells and FOXP3 in regulatory T cells. Human memory CD8⁺ T cells downregulate PD-1 and, along with monocytes, exert in vivo antitumor function. In xenograft and immunocompetent CLL mouse models, trabectedin has antileukemic effects and antitumor impact on the myeloid and lymphoid cells compartment. It depletes myeloid-derived suppressor cells and tumor-associated macrophages and increases memory T cells. Trabectedin also blocks the PD-1/PD-L1 axis by targeting PD-L1⁺ CLL cells, PD-L1⁺ monocytes/macrophages, and PD-1⁺ T cells. Thus, trabectedin behaves as an immunomodulatory drug with potentially attractive therapeutic value in the subversion of the protumor microenvironment and in overcoming chemoimmune resistance.

High ten-year remission rates following rituximab, fludarabine, mitoxantrone and dexamethasone (R-FND) with interferon maintenance in indolent lymphoma: Results of a randomized Study

We report a single-centre, randomized study evaluating the efficacy and safety of concurrent fludarabine, mitoxantrone, dexamethasone (FND) and rituximab versus sequential FND followed by rituximab in 158 patients with advanced stage, previously untreated indolent lymphoma, enrolled between 1997 and 2002. Patients were randomized to 6-8 cycles of FND followed by 6 monthly doses of rituximab or 6 doses of rituximab given concurrently with FND. All patients who achieved at least a partial response received 12 months of interferon (IFN) maintenance. Median ages were 54 and 55 years. The two groups were comparable with the exception of a higher percentage of females (65% vs. 43%) and baseline anaemia (23% vs. 11%) in the FND followed by rituximab group. Complete response/unconfirmed complete response rates were 89% and 93%. The most frequent grade ≥ 3 toxicity was neutropenia (86% vs. 96%). Neutropenic fever occurred in 21% and 16%. Late toxicity included myelodysplastic syndrome (n = 3) and acute myeloid leukaemia (n = 5). With 12·5 years of follow-up, no significant differences based on treatment schedule were observed. 10-year overall survival estimates were 76% and 73%. 10-year progression-free survival estimates were 52% and 51%. FND with concurrent or sequential rituximab, and IFN maintenance in indolent lymphoma demonstrated high response rates and robust survival.

Selectivity in Small Molecule Splicing Modulation

The dysregulation of RNA splicing is a molecular hallmark of disease, including different and often complex cancers. While gaining recognition as a target for therapeutic discovery, understanding the complex mechanisms guiding RNA splicing remains a challenge for chemical biology. The discovery of small molecule splicing modulators has recently enabled an evaluation of the mechanisms of aberrant splicing. We now report on three unique features within the selectivity of splicing modulators. First, we provide evidence that structural modifications within a splicing modulator can alter the splicing of introns in specific genes differently. These studies indicate that structure activity relationships not only have an effect on splicing activity but also include specificity for specific introns within different genes. Second, we find that these splicing modulators also target the mRNAs encoding components of the spliceosome itself. Remarkably, this effect includes the genes for the SF3B complex, a target of pladienolide B and related splicing modulators. Finally, we report on the first observation of a temporal phenomenon associated with small molecule splicing modulation. Combined, these three observations provide an important new perspective for the exploration of splicing modulation in terms of both future medicinal chemistry programs as well as understanding the key facets underlying its timing.

Molecular chemotherapy and chemotherapy: a new front against late-stage hormone-refractory prostate cancer

PURPOSE

Stemming from its inherent heterogeneity, single-agent treatments are essentially ineffective against castration-resistant prostate cancer (CRPC). Thus, clinically relevant regimens that harness different modalities to maximize treatment efficacy without increasing cumulative toxicities are urgently needed. Based on this rationale, we investigated whether a novel combination of purine nucleoside phosphorylase-mediated, gene-directed enzyme-prodrug therapy (PNP-GDEPT) with docetaxel against CRPC has superior efficacy in comparison with individual treatments.

METHODS

The in vitro cell growth inhibition in differentially treated murine and human CRPC cell lines was established using a cell-viability assay. The extent of synergy, additivity, or antagonism between treatments was evaluated using CalcuSyn statistical analyses. The local and systemic effects of docetaxel and/or PNP-GDEPT were tested in both immunodeficient and immunocompetent mice against human and murine CRPC tumors, respectively. Subsequently, immunohistochemical analyses and an evaluation of serum cytokine and serum toxicity profiles were conducted to characterize the differential host responses to treatment.

RESULTS

The combined use of PNP-GDEPT and docetaxel led to strong synergistic cell killing in vitro. Compared with the individual modalities, a combination of the 2 led to a marked reduction in "local and distant" tumor growth in vivo, and importantly, with lowered doses and without additional toxicities. Immunomodulation was indicated by enhanced immune cell infiltration and altered serum cytokine levels. Furthermore, a lowering of T-helper type 2 cytokines, MCP-1, interleukin (IL)-4, IL-6, and IL-10 marked lower tumor burden and enhanced treatment efficacy.

CONCLUSION

PNP-GDEPT and docetaxel are a potent combination against CRPC in immunocompetent and immunodeficient settings; these outcomes have implications of translational potential for improved treatment and management of CRPC patients.

Sensitivity analysis of cost factors for various therapy options in the treatment of follicular lymphoma

BACKGROUND

In Germany, patients with relapsed follicular non-Hodgkin's lymphoma do not all receive the same treatment. In this study, 3 therapy regimens were analyzed which were considered to be similar. With the goal of determining the treatment option with the lowest direct costs whilst maintaining the same degree of effectiveness, a cost analysis model was established and applied by way of example to the existing illness constellation.

METHODS

The German doctors' fee scale (Einheitlicher Bewertungsmassstab, EBM) valid until 2005 served as the basis for the calculation of medical services within the scope of the present statutory health insurance guidelines. A virtual standard patient was constructed for the cost model and treated with the different therapy regimens. The incidences of individual adverse events described in literature served as the basis for the characterization of the average toxicity of the respective treatment methods.

RESULT

The overall costs result from the sum of the treatment costs and the toxicity-related costs. The effect of additional interventions on the overall cost was also examined.

CONCLUSION

Whereas the accompanying documentation of costs in clinical studies is organizationally complex and very tedious, the model applied here offers a reliable method of quantifying the costs of the different therapy regimens. It permits the comparison of different treatment alternatives, and it enables, by means of a cost variance analysis, the identification of cost drivers and less expensive measures within a therapy method.

Treatment of advanced mycosis fungoides/Sézary syndrome with fludarabine and potential adjunctive benefit to subsequent extracorporeal photochemotherapy

BACKGROUND

Purine analogues [fludarabine monophosphate (FAMP); deoxycoformycin and 2-chlorodeoxyadenosine) and extracorporeal photochemotherapy (ECP) have been suggested to be active agents in advanced cutaneous T-cell lymphoma (CTCL) patients.

OBJECTIVES

To explore further the clinical efficacy and safety of FAMP monochemotherapy in advanced CTCL and to evaluate if the sequential association of ECP to FAMP in selected patients may improve the response rate (RR) and/or lengthen the remission duration.

PATIENTS AND METHODS

Forty-four CTCL patients [17 Sézary syndrome (SS); 26 mycosis fungoides (MF), stage IIB-IV or with peripheral blood involvement; one MF associated with lymphomatoid papulosis (LyP)] were enrolled in this pilot cohort study. All the patients received FAMP 25 mg m(-2) 5 days monthly; 19 patients (43.2%) underwent ECP after FAMP was discontinued. The majority of patients with erythrodermic CTCL or peripheral blood involvement underwent the combined FAMP-ECP schedule.

RESULTS

After a median follow-up of 4.2 years, the overall FAMP RR was 29.5% (13/44); a higher RR was obtained in SS (35.3%) than in MF patients (25.9%). According to the treatment group, the RR of the FAMP-ECP group (63.2%) was significantly higher than that of the FAMP monotherapy group (24%; P=0.021). No statistically significant difference was found in time-to-progression (TTP) or survival by therapy group, even if the TTP of the patients treated with the FAMP-ECP combination therapy was higher (median 13 vs. 7 months). A decrease or a normalization in the CD4+CD26- circulating subset was observed in responding patients, paralleling the reduction in the circulating Sézary cells.

CONCLUSIONS

FAMP confirms its clinical activity as a single agent in SS; conversely, FAMP results do not compare favourably with other therapeutic approaches for advanced stage MF patients. The sequential association of ECP after FAMP seems to increase the RR, even if future randomized studies are needed to confirm these results.

Costs of drug delivery for CHOP, COP/CVP, and fludarabine: an international assessment

OBJECTIVES

The purpose of this analysis was to assess the real-life direct costs of drug delivery for frequently used chemotherapeutic regimens in patients with relapsed low-grade non-Hodgkin's lymphoma (NHL).

METHODS

This was a retrospective analysis of direct costs of drug delivery (acquisition plus administration) of relapsed low-grade NHL in 424 patients in Canada, Germany, and Italy. Results were expressed as an average treatment cost per patient for six cycles of chemotherapy. Exchange rates used were $1 (Canada)= currency 0.672, 1 DM (Germany)= currency 0.511, and 1 Lit (Italy)= currency 0.000517.

RESULTS

Direct costs of drug delivery were greater for inpatients receiving fludarabine (Canada currency 12,669; Italy currency 13,027) than for CHOP (Canada currency 7856; Germany currency 7218; Italy currency 4251) or COP/CVP (Canada currency 7360; Germany currency 8449). Treatment administration setting was a major cost driver with inpatient treatment up to 9-fold more expensive than the same regimen given to outpatients. Drug administration costs comprised the largest proportion of the total for each regimen in the inpatient setting (69-98%). Costs of drug delivery in the outpatient setting were 10% to 65% of those in the inpatient setting. Again, fludarabine was more expensive (Italy currency 8493; Canada currency 7269) than CHOP (Canada currency 4403; Germany currency 2150; Italy currency 1264) and COP/CVP (Canada currency 3009; Germany currency 867). Administration costs were 2.5- to 15-fold higher for inpatients compared to outpatients.

CONCLUSIONS

Costs of drug administration are a major driver for total direct treatment costs in the treatment of relapsed low-grade NHL and are at least as important as drug acquisition costs. Drug administration practices, in terms of inpatient or outpatient treatment, are a major factor in determining overall direct costs. Therapeutic strategies, which offer shortened treatment duration and/or a simple mode of administration, are likely to be economically attractive.

Progress and promise in the treatment of indolent lymphomas

In the era of conventional alkylating agent-based chemotherapy, advanced stage indolent lymphoma has been considered incurable. The failure of our traditional therapies to cure these patients, coupled with the indolent course of the disease and the elderly population affected, has fostered a nihilistic attitude about the treatment of these diseases. Twenty years ago, in the absence of interesting alternatives to alkylating agents, judicious use and reuse of alkylators was perhaps the best we could do. There are now many reasons for optimism and excitement in the treatment of these diseases, including the availability of promising agents such as interferon-alpha, the nucleoside analogues, and rituximab. Radioimmunotherapy will also likely play a role in future therapy programs. Allogeneic stem cell transplantation is a high-risk approach that is not an option for all patients, but it has the potential to cure patients, even in the setting of relapse. Mini-allogeneic transplantation may permit an approach to allogeneic transplantation that is better tolerated than standard transplant strategies. In addition to these therapy options, biological insights have provided new options for monitoring patients. Molecular monitoring (polymerase chain reaction for bcl-2) is a stringent measure of short-term treatment efficacy, and one that correlates with durability of remission, i.e., it is a surrogate marker by which to judge treatment efficacy. There used to be a limited number of conventional treatment approaches, which consistently failed. The pendulum has swung. There are now many promising new options. It is time to plan and conduct trials that are geared for success.

Current treatment of follicular non-Hodgkin's lymphoma

56200 new cases of NHL are expected to be diagnosed in the United States (US) per year. For reasons that are not fully understood, the number of new cases per year has nearly doubled in the past three decades. Most patients with follicular lymphoma are over 50 years of age and present with widespread disease at diagnosis. Nodal involvement is very common, often accompanied by splenic and bone marrow disease. Despite the advanced stage, the median survival ranges from 8 to 12 years. The vast majority of patients with advanced stage follicular lymphoma are not cured using the current therapeutic options. The rate of relapse is fairly consistent over time, even in patients who have achieved complete responses (CRs) to treatment. Therapeutic options in follicular NHL include watchful waiting, oral alkylating agents, purine nucleoside analogues, combination chemotherapy, interferon and monoclonal antibodies. Radiolabelled monoclonal antibodies, autologous or allogeneic bone marrow or peripheral stem cell transplantation are under current clinical evaluation. The approval of rituximab, an unconjugated chimeric antibody against the CD20 antigen for the treatment of relapsed follicular B-cell NHL marked a milestone in the development of antibody treatment. In addition, newer approaches like radioimmunoconjugates with myeloablative activity induced response rates of 80-100% in heavily pretreated patients. Various clinical trials combining monoclonal antibodies with conventional therapies are currently ongoing to determine whether these new biological agents will alter the natural history of follicular lymphoma.

Stem cell transplantation (SCT) for Waldenstrom's macroglobulinemia (WM)

Waldenstrom's macroglobulinemia (WM) is a low-grade lymphoplasmacytoid malignancy of unknown etiology. It primarily affects elderly patients and is characterized by a monoclonal IgM component, varying degrees of cytopenias, lymphadenopathy and manifestations related to hyperviscosity syndromes. WM is usually treated with single agent nucleoside analogues or alkylating agents that often provide high response rates and durable remissions. Recurrence of the disease after primary therapy is not uncommon, and resistance to both alkylating agents and nucleoside analogs eventually emerges. Small numbers of patients have undergone high-dose chemotherapy (HDC) with either autologous (n = 24) or allogeneic (n = 6) stem cell transplantation (SCT) as treatment for this disease. Most patients in both groups achieved remission. Results are promising and a more in-depth analysis of possible applications of this treatment modality is attempted with this mini-review.