A phase 1 study of nifurtimox in patients with relapsed/refractory neuroblastoma.

The primary aim of this phase 1 study was to determine the maximum tolerated dose (MTD) and evaluate the safety of nifurtimox alone and in combination with cyclophosphamide and topotecan in multiple relapsed/refractory neuroblastoma pediatric patients. The secondary aim was to evaluate the pharmacokinetics of nifurtimox and the treatment response. To these ends, we performed a phase 1 dose escalation trial of daily oral nifurtimox with toxicity monitoring to determine the MTD, followed by 3 cycles of nifurtimox in combination with cyclophosphamide and topotecan. Samples were collected to determine the pharmacokinetic parameters maximum concentration, time at which maximum concentration is reached, and area under the curve between 0 and 8 hours. Treatment response was evaluated by radiographic and radionuclide (I-metaiodobenzylguanidine) imaging, measurement of urinary catecholamines, and clearance of bone marrow disease. We determined the MTD of nifurtimox to be 30 mg/kg/d. The non-dose-limiting toxicities were mainly nausea and neuropathy. The dose-limiting toxicities of 2 patients at 40 mg/kg/d were a grade 3 pulmonary hemorrhage and a grade 3 neuropathy (reversible). Overall, nifurtimox was well tolerated by pediatric patients at a dose of 30 mg/kg/d, and tumor responses were seen both as a single agent and in combination with chemotherapy. A Phase 2 study to determine the antitumor efficacy of nifurtimox is currently underway.

Clinical aspects of pharmacogenetics of pain and co-morbidities of emotional distress.

The majority of patients treated for cancer will have pain at some point in their journey. It will be due to the disease (e.g. bone metastasis, fracture, organ invasion) or from iatrogenic causes (chemotherapy, surgery or radiation). A large number of patients will also have depression. Since pain and depression share common biological pathways and even neuro-transmitters it is not surprising that a comorbidity of pain is depression. It has already been reported that patients in severe pain are 4 times less likely to respond to therapy for depression. In recent years, especially in the era of molecular biology and post-genomic a wealth of data in the arena of pharmacogenetics/genomics has shed more light on cancer related symptoms such as pain and related them to the cytokine pathways, especially the interleukins and tumor necrosis factor (TNF). When we remember that the synonym for TNF is "cachectin" it is no wonder patients feel awful when there is active disease and the body trying to mount a response. Neuroendocrine, immunomodulatory and inflammatory pathways are likely important in the pathophysiology of pain and depression. These realizations are in addition to a greater understanding of afferent pathways for pain perception, of the multiple opioid receptors, the effects of hormones and catechol metabolism and other transmitters. Moreover we already have a more complete under-standing of drug metabolism, especially of the opioids, the back bone of all pain treatment. There are a number of single nucleotide polymorphisms (SNPs) in the genes important for drug metabolism such as CYP2D6, a cytochrome responsible for about 25% of all drugs. There are about 90 variants already reported and rapid and slow metabolizers need very different doses of codeine or morphine. We are entering an era of having the capability to develop personalized treatment for our patients nociceptive pain, neuropathic pain and depression. The convergence of new knowledge in the molecular biology and pharmacogenetic era should allow us to treat our patients suffering with a resultant increased quality of life even while we strive to cure them of their malignancy.

Functional folate receptor alpha is elevated in the blood of ovarian cancer patients.

BACKGROUND: Despite low incidence, ovarian cancer is the fifth leading cause of cancer deaths and it has the highest mortality rate of all gynecologic malignancies among US women. The mortality rate would be reduced with an early detection marker. The folate receptor alpha (FRalpha) is one logical choice for a biomarker because of its prevalent overexpression in ovarian cancer and its exclusive expression in only a few normal tissues. In prior work, it was observed that patients with ovarian cancer had elevated serum levels of a protein that bound to a FRalpha-specific monoclonal antibody relative to healthy individuals. However, it was not shown that the protein detected was intact functional FRalpha. In the current study, the goal was to determine whether ovarian cancer patients (n = 30) had elevated serum levels of a fully functional intact FRalpha compared to matched healthy controls (n = 30). METHODOLOGY/PRINCIPAL FINDINGS: FRalpha levels in serum were analyzed by two methods, immunoblotting analysis and a radiolabeled folic acid-based microfiltration binding assay. Using the immunoassay, we observed that levels of FRalpha were higher in serum of ovarian cancer patients as compared to controls. Similar results were also observed using the microfiltration binding assay, which showed that the circulating FRalpha is functional. Importantly, we also found that the levels of FRalpha were comparable between early and advanced stage patients. CONCLUSIONS: Our results demonstrate that ovarian cancer patients have elevated levels of functional intact FRalpha. These findings support the potential use of circulating FRalpha as a biomarker of early ovarian cancer.

Folate homeostasis in cerebrospinal fluid during therapy for acute lymphoblastic leukemia.

The neurotoxic effects of therapy for childhood acute lymphoblastic leukemia can result in leukoencephalopathy or measurable deficits in cognitive function. However, there are no validated biomarkers that allow the identification of those patients at greatest risk. With the objective of identifying such predictors, cerebrospinal fluid collected from 53 patients over 2.5 years of therapy for childhood acute lymphoblastic leukemia was retrospectively studied. Cerebrospinal fluid folate, concentrated relative to serum folate prior to therapy, dropped during the first month of therapy and remained below baseline throughout treatment. Cerebrospinal fluid homocysteine was inversely related to cognitive function prior to treatment. Oral methotrexate was associated with decreased cerebrospinal fluid folate and increased cerebrospinal fluid homocysteine, but these changes were not seen with oral aminopterin. Of 36 patients who had imaging after completion of therapy, 9 had periventricular or subcortical white matter abnormalities consistent with leukoencephalopathy. Peak cerebrospinal fluid tau concentrations during therapy were higher among patients who had leukoencephalopathy after completion of therapy than among those with normal imaging studies at the end of therapy. If confirmed prospectively, these markers may allow the identification of those patients at greatest risk of developing treatment-induced neurocognitive dysfunction, thus guiding preventive interventions.

Use of a novel genetic mouse model to investigate the role of folate in colitis-associated colon cancer.

Inflammatory bowel disease (IBD) patients are at high risk for developing folate deficiency and colon cancer. Since it is difficult to study the subtle global and gene-specific epigenetic mechanisms involved in folate-mediated tumor initiation and promotion, we have generated genetically modified mouse models by targeting the reduced folate carrier (RFC1) and folate-binding protein (Folbp1) genes. The transgenic mice were fed semi-purified diets for 8 weeks containing either normal (2 mg) or deficient (0.1 mg folate/kg diet) levels of folate. Compound heterozygous mice (Folbp1(+/-); RFC1(+/-)) fed an adequate folate diet exhibited a reduction in plasma folate concentrations compared to heterozygous (Folbp1(+/-)) and littermate wild-type mice (P<.05). In contrast, no differences were observed in colonic mucosa. Consumption of a low folate diet significantly reduced (three- to fourfold) plasma and tissue folate levels in all animal models, although plasma homocysteine levels were not altered. In order to elucidate the relationship between folate status and inflammation-associated colon cancer, animals were injected with azoxymethane followed by dextran sodium sulphate treatment in the drinking water. Mice were fed a normal folate diet and were terminated 5 weeks after carcinogen injection. The number of high multiplicity aberrant crypt foci per centimeter of colon was significantly elevated (P<.05) in compound Folbp1(+/-); RFC1(+/-) (3.5+/-0.4) mice as compared to Folbp1(+/-) (1.9+/-0.3) and wild-type control mice (1.1+/-0.1). These data demonstrate that the ablation of two receptor/carrier-mediated pathways for folate transport increases the risk for developing inflammation-associated colon cancer.