Long-term remission in an elderly patient with mantle cell leukemia treated with low-dose cyclophosphamide

Antiangiogenic metronomic therapy for children with recurrent embryonal brain tumors

BACKGROUND

Median survival time of recurrent embryonal brain tumors is short regardless of salvage chemotherapy used. An evolving alternative approach to conventional chemotherapy is to target neovascularization by interfering with tumor angiogenesis at various levels.

PROCEDURE

From November 2006 to December 2010, 16 patients (median age: 9 years) with recurrent (9 first, 7 multiple) embryonal brain tumors were treated with an antiangiogenic multidrug combination regimen (bevacizumab, thalidomide, celecoxib, fenofibrate, etoposide, and cyclophophamide) and additional intraventricular therapy (etoposide and liposomal cytarabine).

RESULTS

At a median of 33 months, 10/16 patients are alive. 4/4 patients with CNS primitive neuroectodermal tumors (CNS PNET) and 1/7 patients with medulloblastoma (MB) died of tumor progression during the first year. Another patient with MB died of an accident after 23 months, the remaining five patients with MB are alive for 12, 33, 33, 37, and 58 months. For the seven patients with MB, both overall survival (OS) and event free survival (EFS) after 6 months was 100%, after 12 months 85.7 ± 13%, and after 24 months 68.6 ± 19%. In contrast, for patients with CNS PNET, both OS and EFS after 6 months was 75.0 ± 22% and 0.0% and all patients had died by 12 months. Low-dose oral etoposide and cyclophosphamide was reduced after a median of 2 months and discontinued after a median of 11 months. Toxicities were manageable and therapy was generally well tolerated.

CONCLUSION

Our results suggest that the chosen antiangiogenic drug combination is particularly beneficial for patients with MB and warrants further investigation.

Effects of prophylactic administration of bacteriophages to immunosuppressed mice infected with Staphylococcus aureus

BACKGROUND

Bacteriophages can be successfully applied to treat infections caused by antibiotic-resistant bacteria. Until now no attempts have been undertaken to treat infections in immunosuppressed patients with phages. In this work we investigated the prophylactic efficacy of specific bacteriophages in CBA mice treated with cyclophosphamide (CP) and infected with Staphylococcus aureus.

RESULTS

High numbers of bacterial colony-forming units in the organs as well as elevated tumor necrosis factor and interleukin-6 serum concentrations in CP-treated and S. aureus-infected mice were significantly lowered upon application of phages. The phages markedly increased the percentage of circulating neutrophils and immature cells from the myelocytic and lymphocytic lineages in CP-treated, S. aureus-infected mice as well as of myelocytes and immature neutrophils in the bone marrow. In addition, phages stimulated in such mice generation of specific agglutinins against S. aureus.

CONCLUSION

Application of specific phages to immunosuppressed mice prior to infection with S. aureus proved very effective, suggesting a potential benefit of phage therapy in immunocompromised patients experiencing bacterial infections.

Phase II study of metronomic chemotherapy for recurrent malignant gliomas in adults

Preclinical evidence suggests that continuous low-dose daily (metronomic) chemotherapy may inhibit tumor endothelial cell proliferation (angiogenesis) and prevent tumor growth. This phase II study evaluated the feasibility of this antiangiogenic chemotherapy regimen in adults with recurrent malignant gliomas. The regimen consisted of low-dose etoposide (35 mg/m2 [maximum, 100 mg/day] daily for 21 days), alternating every 21 days with cyclophosphamide (2 mg/kg [maximum, 100 mg/day] daily for 21 days), in combination with daily thalidomide and celecoxib, in adult patients with recurrent malignant gliomas. Serum and urine samples were collected for measurement of angiogenic peptides. Forty-eight patients were enrolled (15 female, 33 male). Twenty-eight patients had glioblastoma multiforme (GBMs), and 20 had anaplastic gliomas (AGs). Median age was 53 years (range, 33-74 years), and median KPS was 70 (range, 60-100). Therapy was reasonably well tolerated in this heavily pretreated population. Two percent of patients had partial response, 9% had a minor response, 59% had stable disease, and 30% had progressive disease. For GBM patients, median progression-free survival (PFS) was 11 weeks, six-month PFS (6M-PFS) was 9%, and median overall survival (OS) was 21 weeks. For AG patients, median PFS was 14 weeks, 6M-PFS was 26%, and median OS was 41.5 weeks. In a limited subset of patients, serum and urine angiogenic peptides did not correlate with response or survival (p > 0.05). Although there were some responders, this four-drug, oral metronomic regimen did not significantly improve OS in this heavily pretreated group of patients who were generally not eligible for conventional protocols. While metronomic chemotherapy may not be useful in patients with advanced disease, further studies using metronomic chemotherapy combined with more potent antiangiogenic agents in patients with less advanced disease may be warranted.

Lactoferrin accelerates reconstitution of the humoral and cellular immune response during chemotherapy-induced immunosuppression and bone marrow transplant in mice

Experimental evidence from previous studies supports the conclusion that orally administered lactoferrin (LF) restores the immune response in mice treated with a sublethal dose of cyclophosphamide (CP). The aim of this study was to elucidate potential benefit of LF in mice undergoing chemotherapy with busulfan (BU) and CP, followed by intravenous (i.v.) injection of bone marrow cells. CBA mice were treated orally with busulfan (4 mg/kg) for 4 consecutive days, followed by two daily doses of CP delivered intraperitoneally (i.p.) at a dose of 100 mg/kg and reconstituted next day with i.v. injection of 10(7) syngeneic bone marrow cells. One group of these mice was given LF in drinking water (0.5% solution). After treatment, mice were immunized with ovalbumin (OVA) to subsequently measure delayed type hypersensitivity responsiveness and with sheep red blood cells to determine humoral immunity by evaluation of splenic antibody-forming cells. As expected, both humoral and cellular immune responses of mice that were treated with these chemotherapeutic agents was markedly impaired. Here we report that this impairment was remarkably attenuated by oral administration of LF. Humoral immunity fell to levels that were 66-88% lower than that of untreated animals. Humoral immunity of LF-treated animals was equivalent to that of untreated mice within 1 month. Cellular immune responses were inhibited by chemotherapy treatment to a lesser degree, reaching levels that were approximately 50% lower than those of untreated animals. Again, LF mitigated this decrease, resulting in responses that were only slightly lower than those observed in untreated animals. Furthermore, when mice were given a lethal dose of BU (4 x 25 mg daily doses, i.p.) followed by a bone marrow transplant, LF caused enhanced lympho-, erythro-, and myelopoiesis in the bone marrow and appearance of transforming splenic lymphoblasts, similar to effects caused by administration of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). In summary, our study suggests that LF may be a useful agent to accelerate restoration of immune responsiveness induced by chemotherapy in bone marrow transplant recipients.

A feasibility trial of antiangiogenic (metronomic) chemotherapy in pediatric patients with recurrent or progressive cancer

Standard chemotherapeutic drugs, when modified by the frequency and dose of administration, can target angiogenesis. This approach is referred to as antiangiogenic chemotherapy, low-dose chemotherapy, or metronomic chemotherapy. This study evaluated the feasibility of 6 months of metronomic chemotherapy, its toxicity and tolerability, surrogate markers of activity, and preliminary evidence of activity in children with recurrent or progressive cancer. Twenty consecutive children were enrolled and received continuous oral thalidomide and celecoxib with alternating oral etoposide and cyclophosphamide every 21 days for a planned duration of 6 months using antiangiogenic doses of all four drugs. Surrogate markers including bFGF, VEGF, endostatin, and thrombospondin were also evaluated. Therapy was well tolerated in this heavily pretreated population. Toxicities (predominantly reversible bone marrow suppression) responded to dose modifications. Sixty percent of the patients received less than the prescribed 6 months of therapy due to toxicity (one case of deep vein thrombosis), personal choice (1 patient), or disease progression (10 patients). Forty percent of the patients completed the 6 months of therapy, resulting in prolonged or persistent disease-free status. One quarter of all patients continue to be progression free more than 123 weeks from starting therapy. Sixteen percent of patients showed a radiographic partial response. Only elevated thrombospondin-1 levels appeared to correlate with prolonged response. This oral antiangiogenic chemotherapy regimen was well tolerated in this heavily pretreated pediatric population, which showed prolonged or persistent disease-free status, supporting the continued study of antiangiogenic/metronomic chemotherapy in human clinical trials.

Enhanced clearance of Escherichia coli and Staphylococcus aureus in mice treated with cyclophosphamide and lactoferrin

Previous studies on cyclophosphamide (CP)-immunocompromised mice showed accelerated reconstitution of immune system function following oral treatment with lactoferrin (LF). The aim of this investigation was to evaluate the ability of mice, treated with a sublethal dose of CP and given LF, to combat bacterial infections. Mice were injected with a single, intraperitoneal dose of CP (350 mg/kg body weight). One group of CP-treated mice was also given LF in drinking water (0.5% solution) for 14 days. Untreated and LF-treated mice served as controls. On day 15 following CP administration, mice were infected intravenously with 10(8) Escherichia coli or 5 x 10(7) Staphylococcus aureus. Twenty-four hours later, the number of colony-forming units (CFU) in spleens and livers were determined. Phenotypic analysis of blood leukocytes was determined, as well as the ability of splenic and peritoneal cells to produce IL-6 spontaneously and in the presence of lipopolysaccharide (LPS). Treatment with CP, or with CP and LF, led to profound reduction of E. coli CFU in the liver and the spleen; treatment with LF alone had significant inhibitory effects on organ enumerated CFU. S. aureus CFUs were also significantly reduced in spleens of mice treated with CP or CP/LF and, to a lesser degree, after LF alone. These effects were also significantly reduced in the livers. Analysis of blood cellular phenotype revealed total number of peripheral leukocytes was lower in the CP-treated group (52.6%) but not significantly different from control values in CP/LF and LF-treated groups (90.7% and 104.6%, respectively). Conversely, percentage of blood neutrophils was markedly elevated in CP and CP/LF groups--62% and 42.5% vs. 18.4% in controls. These findings were accompanied by production of IL-6 by splenic and peritoneal cells which was significantly increased in CP- and CP/LF-treated groups. It was concluded that the increased clearance of bacteria in the organs of mice treated with CP and CP/LF may result from a rise in the number of neutrophils infiltrating the organs and contributing to accelerated clearance of bacteria. The study also suggests that the ability of cells from CP- and CP/LF-treated mice to produce significantly more IL-6 may also contribute to increased resistance to infections. Lastly, together with our previous data, this study indicates that LF used to reconstitute the antigen-specific immune response in CP-treated mice does not impair their resistance to infection.

Orally administered lactoferrin restores humoral immune response in immunocompromised mice

Cyclophosphamide (CP) is an anti-tumor drug commonly used in the chemotherapy of human cancer and autoimmune diseases. In our previous studies, we have demonstrated that lactoferrin (LF), given orally to CP-immunosuppressed mice, could reconstitute a T cell mediated immune response by the renewal of the T cell population. The aim of this present study was to evaluate the effects of LF on humoral responses in mice treated with cyclophosphamide. We demonstrate that a single, sublethal dose of cyclophosphamide (400 mg/kg body weight) profoundly inhibited the humoral immune response of CBA mice to sheep red blood cells (SRBC), as measured by the number of antibody forming cells (AFC) in the spleen after 5 weeks following CP treatment. Administration of 0.5% bovine LF in drinking water for 5 weeks partially reconstituted the AFC number (30-40% of the control values, but 7-10x more than in CP-treated controls). Determination of T and B cell levels in the spleens by flow cytometry revealed that the content of CD3+ and CD4+ as well as Ig+ splenocytes was elevated in the immunocompromised mice treated with LF. In addition, the number of peritoneal macrophages was partially restored following LF treatment. Evaluation of the proliferative response to concanavalin A (ConA) and pokeweed mitogen (PWM) demonstrated that the diminished reactivity of splenocytes from CP-treated mice was significantly enhanced by LF. In summary, we conclude that the prolonged, oral treatment of immunocompromised mice with LF led to partial reconstitution of the humoral response, associated with elevation of T and B cell and macrophage content and the proliferative response of splenocytes to mitogens.

Metronomic therapy with cyclophosphamide and dexamethasone for prostate carcinoma

BACKGROUND

The current study was designed to evaluate the efficacy and toxicity of the continuous oral administration of a combination of cyclophosphamide (50 mg/day given in the morning) and dexamethasone (1 mg/day given in the evening) in patients with prostate specific antigen (PSA) progression despite single or multiagent hormone therapy and antiandrogen withdrawal.

METHODS

The authors retrospectively evaluated the medical records of all patients with prostate carcinoma who were treated with dexamethasone and cyclophosphamide and who were unable to participate in Phase II drug trials or had failed previous chemotherapy regimens.

RESULTS

Using clinical response guidelines set forth by the Prostate Specific Antigen Working Group, 29% of patients were found to have a > or = 80% reduction in PSA, 39% were found to have a 50-79% reduction in PSA, 6% were found to have a < 50% decrease in PSA, and 26% experienced disease progression while receiving treatment. The duration of response was 8 months (95% confidence interval [95% CI], 4-10 months). The duration of treatment was 9 months (95% CI, 6-14 months). The treatment was reported to be well tolerated with side effects being primarily bruising, Cushingoid facies, and gastrointestinal distress.

CONCLUSIONS

In the current study, low-dose dexamethasone and cyclophosphamide demonstrated efficacy as salvage therapy in the treatment of patients with hormone-refractory prostate carcinoma.