Blockage of the Na-K-ATPase signaling-mediated oxidant amplification loop elongates red blood cell half-life and ameliorates uremic anemia induced by 5/6th PNx in C57BL/6 mice.

We have previously demonstrated that the Na-K-ATPase signaling-mediated oxidant amplification loop contributes to experimental uremic cardiomyopathy and anemia induced by 5/6th partial nephrectomy (PNx). This process can be ameliorated by systemic administration of the peptide pNaKtide, which was designed to block this oxidant amplification loop. The present study demonstrated that the PNx-induced anemia is characterized by marked decreases in red blood cell (RBC) survival as assessed by biotinylated RBC clearance and eryptosis as assessed by annexin V binding. No significant change in iron homeostasis was observed. Examination of plasma samples demonstrated that PNx induced significant increases in systemic oxidant stress as assessed by protein carbonylation, plasma erythropoietin concentration, and blood urea nitrogen. Systemic administration of pNaKtide, but not NaKtide (pNaKtide without the TAT leader sequence) and a scramble "pNaKtide" (sc-pNaKtide), led to the normalization of hematocrit, RBC survival, and plasma protein carbonylation. Administration of the three peptides had no significant effect on PNx-induced increases in plasma erythropoietin and blood urea nitrogen without notable changes in iron metabolism. These data indicate that blockage of the Na-K-ATPase signaling-mediated oxidant amplification loop ameliorates the anemia of experimental renal failure by increasing RBC survival.NEW & NOTEWORTHY The anemia of CKD is multifactorial, and the current treatment based primarily on stimulating bone marrow production of RBCs with erythropoietin or erythropoietin analogs is unsatisfactory. In a murine model of CKD that is complicated by anemia, blockade of Na-K-ATPase signaling with a specific peptide (pNaKtide) ameliorated the anemia primarily by increasing RBC survival. Should these results be confirmed in patients, this strategy may allow for novel and potentially additive strategies to treat the anemia of CKD.

Low ferroportin expression in AML is correlated with good risk cytogenetics, improved outcomes and increased sensitivity to chemotherapy.

Iron metabolism is altered in a variety of cancers; however, little is known about the role of iron metabolism in the biology and response to therapy of acute myeloid leukemia (AML). Here we show that SLC40A1, the gene encoding the iron exporter ferroportin (FPN), is variably expressed among primary AMLs and that low levels are associated with good prognosis and improved outcomes. In particular, core binding factor (CBF) AMLs, which are associated with good outcomes with chemotherapy, consistently have low level of SLC40A1 expression. AML cell lines that expressed relatively low levels of FPN endogenously, or were engineered via gene knockdown, had an increased sensitivity to chemotherapy relative to controls expressing high levels of FPN. Primary FPNlow AML bulk cells also had increased sensitivity to Ara-C treatment, iron treatment and the combination of Ara-C and iron relative to FPNhigh cells. FPNlow leukemic stem cells (LSCs) had decreased viability following addition of iron alone and in combination with Ara-C treatment relative to FPNhigh LSCs. Together these observations suggest a model where FPN mediated iron metabolism may play a role in chemosensitivity and outcome to therapy in AML.

Managing the Risks of Medicines: An Examination of FDA's Application of Criteria for Requiring a REMS.

BACKGROUND: In September 2016, the Food and Drug Administration (FDA) published a draft guidance for industry, FDA's Application of Statutory Factors in Determining When a REMS Is Necessary, that detailed the factors the Agency considers in determining when a Risk Evaluation and Mitigation Strategy (REMS) is necessary. The objective of this study was to determine how the FDA has applied these criteria for newly approved drugs. METHODS: For the 3-year period, 2015-2017, which included a full year of FDA approvals both before and after the issuance of the draft guidance, publicly available FDA reviews were analyzed for all 113 approved products using the criteria outlined in the guidance. RESULTS: Of the 113 products approved, 5 required a REMS. The most cited reasons for not requiring a REMS for the remaining 108 drugs were that risks could be managed via professional labeling (87%), physicians (primarily specialists) were familiar with the management of the risks (76%), the risk profile was similar to other non-REMS marketed products (45%), products were used in a controlled setting (inpatient, infusion center) (30%), and/or safety concerns would be further evaluated by a postmarket study (14%). CONCLUSIONS: A review of Agency risk evaluations indicate that whether physicians are sufficiently familiar with and capable of managing a risk and that the health care setting where the product is administered is conducive to such management are leading factors in determining whether or not to require a REMS.

The late-annotated small ORF LSO1 is a target gene of the iron regulon of Saccharomyces cerevisiae.

We have identified a new downstream target gene of the Aft1/2-regulated iron regulon in budding yeast Saccharomyces cerevisiae, the late-annotated small open reading frame LSO1. LSO1 transcript is among the most highly induced from a transcriptome analysis of a fet3-1 mutant grown in the presence of the iron chelator bathophenanthrolinedisulfonic acid. LSO1 has a paralog, LSO2, which is constitutively expressed and not affected by iron availability. In contrast, we find that the LSO1 promoter region contains three consensus binding sites for the Aft1/2 transcription factors and that an LSO1-lacZ reporter is highly induced under low-iron conditions in a Aft1-dependent manner. The expression patterns of the Lso1 and Lso2 proteins mirror those of their mRNAs. Both proteins are localized to the nucleus and cytoplasm, but become more cytoplasmic upon iron deprivation consistent with a role in iron transport. LSO1 and LSO2 appear to play overlapping roles in the cellular response to iron starvation since single lso1 and lso2 mutants are sensitive to iron deprivation and this sensitivity is exacerbated when both genes are deleted.

Iron depletion results in Src kinase inhibition with associated cell cycle arrest in neuroblastoma cells.

Iron is required for cellular proliferation. Recently, using systematic time studies of neuroblastoma cell growth, we better defined the G1 arrest caused by iron chelation to a point in mid-G1, where cyclin E protein is present, but the cyclin E/CDK2 complex kinase activity is inhibited. In this study, we again used the neuroblastoma SKNSH cells lines to pinpoint the mechanism responsible for this G1 block. Initial studies showed in the presence of DFO, these cells have high levels of p27 and after reversal of iron chelation p27 is degraded allowing for CDK2 kinase activity. The initial activation of CDK2 kinase allows cells to exit G1 and enter S phase. Furthermore, we found that inhibition of p27 degradation by DFO is directly associated with inhibition of Src kinase activity measured by lack of phosphorylation of Src at the 416 residue. Activation of Src kinase occurs very early after reversal from the DFO G1 block and is temporally associated with initiation of cellular proliferation associated with entry into S phase. For the first time therefore we show that iron chelation inhibits Src kinase activity and this activity is a requirement for cellular proliferation.

Risk Evaluation and Mitigation Strategies With Elements to Assure Safe Use: Alignment of the Goals With the Tools to Manage Risk.

The Food and Drug Administration Amendments Act of 2007 gave the FDA the authority to require drug sponsors to submit a risk evaluation and mitigation strategies (REMS) program for those medicines with serious risks such that failure to effectively manage these risks would tip the benefit-risk balance. As of August 8, 2013, the 34 distinct individual and shared REMS programs that have specific elements to assure safe use (ETASU) were reviewed to ascertain the types of risks managed, the goals of the REMS, and the tools that were employed targeting prescribers, health care facilities, pharmacists, and particular conditions for safe use. Most REMS (65%) have a combination of risk mitigation and educational goals, but 4 REMS programs (12%) have exclusively educational goals. Preventing fetotoxicity (25%) is the most common risk managed by REMS with ETASU. Seventy-nine percent of ETASU REMS employ prescriber-based tools that include performing laboratory testing (eg, pregnancy, hepatic enzymes) or monitoring (eg, ophthalmologic examinations, documenting vaccination). The goals of REMS programs should focus on measurable behaviors that directly reduce risk. The tools that are employed should create the appropriate conditions for safe use. With the number of programs and the plethora of tools applied, serious consideration should be given to better integration of risk management into health care and pharmacy systems that are best equipped to manage such risks.

Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points.

Using controlled clinical trials to learn more about acute drug-induced liver injury.

Drug-induced liver injury (DILI) is of major interest to hepatologists and clinicians in general, patients, government regulators, and the pharmaceutical industry. Understanding why this form of injury occurs only in certain individuals has major implications for the development and availability of drug therapies and in the prevention of these events. A single controlled clinical trial may be unlikely to show cases of such rare events, but in the aggregate, clinical trials offer a unique resource for learning more about individual susceptibility and developing truly predictive new biomarkers for DILI. We pose the question as to whether clinical trials could be modified or improved to provide data that would better answer some of the outstanding issues. At a recent (March 2008) public meeting, experts from academia, industry, and regulatory bodies discussed several major issues regarding liver safety in clinical trials including: what signals of liver injury should justify stopping administration of study drug or allowing it to continue; if deliberate rechallenge should be done and under what circumstances; whether patients with liver disease should be included in clinical trials; and what kinds of new biomarkers will be needed to answer these questions more clearly. Past clinical trials have not provided data to settle those issues, and reliance has defaulted to consensus of expert opinions. Modified and better clinical trials with standardized collection of data and biospecimens are probably the best source of new and potentially valuable information to supplant current rules based on consensus of expert opinions and to understand by what mechanisms and how to distinguish those individuals who are susceptible to severe DILI.

Single-dosage pharmacokinetics of sodium ferric gluconate complex in iron-deficient pediatric hemodialysis patients.

BACKGROUND AND OBJECTIVES: The clinical use of sodium ferric gluconate complex in iron-deficient pediatric patients receiving hemodialysis was recently approved. This study was designed to describe the pharmacokinetic parameters of the medication. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Iron-deficient pediatric (< or = 15 yr) hemodialysis patients were randomly assigned to two doses (1.5 and 3.0 mg/kg) of sodium ferric gluconate complex. Blood samples taken during a 1-h infusion and at multiple intervals during 48 h were analyzed for total iron, transferrin-bound iron, and sodium ferric gluconate complex-bound iron. RESULTS: Forty-nine patients (mean age 12.3 +/- 2.5 yr) participated in the study. Mean serum iron concentrations rapidly increased in a dosage-dependent manner. A rapid rise in total serum iron was followed by a slower, less prominent rise in transferrin-bound iron. This was qualitatively confirmed by visualization of the transferrin bands from polyacrylamide gel electrophoresis. Single-dose pharmacokinetics of sodium ferric gluconate complex-bound iron was described using noncompartmental analytical methods. Mean values for the 1.5 mg/Kg dose were as follows: t(1/2) 2.0 +/- 0.7 h, Cmax 1287 mcg/dl, Tmax 1.1 +/- 0.23 h, Cl 0.69 +/- 0.50 L/h, Vd 1.6 +/- 0.6 L, AUC(0-infinity). 9499 +/- 4089 mcg x hr/dl. CONCLUSIONS: The infusion of sodium ferric gluconate complex to pediatric patients who receive hemodialysis appears to result in a delayed transfer of iron to transferrin, likely after an initial movement through the reticuloendothelial system. Differences noted between the pediatric and adult pharmacokinetic data may result from the unique aspects of the study populations and the respective study designs.

Changes in isotretinoin prescribing before and after implementation of the System to Manage Accutane Related Teratogenicity (SMART) risk management program.

PURPOSE: To assess changes in isotretinoin prescribing following the implementation of the System to Manage Accutane Related Teratogenicity (SMART) risk management program. METHODS: Using nationally representative commercial data resources on prescription drug dispensing patterns, surveys of office-based physician practices, and a large, claims database from a pharmacy benefits manager (PBM), we examined the total number of isotretinoin prescriptions (new and refill), prescriber speciality, and patient characteristics (age, gender, severity of acne indication) in the year before (April 2001-March 2002) and the year following (April 2002-March 2003) implementation of the SMART program. RESULTS: In the 12-months prior to SMART, 1 508 000 prescriptions were dispensed for isotretinoin, declining approximately 23% to 1 160 000 prescriptions in the year following SMART. There was little or no change in prescriber specialty, severity of acne, and patient age and gender. CONCLUSION: SMART may have lead to a decrease in isotretinoin prescriptions. Further research is needed to determine whether the reduced number of isotretinoin prescriptions reflects appropriate use or inhibited use resulting in loss of access to the product's benefits.

Expression of vascular endothelial growth factor and proliferation marker MIB1 are influenced by neoadjuvant chemotherapy in locally advanced breast cancer.

Neoadjuvant chemotherapy (NACT) has become the standard of care for patients with locally advanced breast cancer (LABC). This was a retrospective review of 21 consecutive women who received NACT as initial treatment of LABC, followed by surgical excision. The pre- and post-treatment breast specimens and post-treatment axillary lymph nodes with metastases were immunostained to evaluate for proliferative index (PI) (MIB-1 Immunotech) and vascular endothelial growth factor (VEGF) expression (Santa Cruz, CA, clone A-20). Thirteen of the 21 patients (62%) had more than 50% tumor shrinkage following NACT. The breast's mean PI decreased from 47.86% to 23.95% after treatment (P = 0.005). The mean PI in the post-treatment lymph nodes was 24.47%. A nodal post-NACT PI of less than 10% and progesterone receptor-positive tumor status were associated with better survival, as all such patients are alive. A high PI after NACT was associated with recurrence or death. All of the patients who showed an excellent clinical response had either a decrease in the PI or an absence of a high level of VEGF after NACT. Most patients exhibited persistent expression of VEGF after NACT. Pathologic response in the primary tumor did not correlate with the response in the lymph nodes or with overall survival. NACT reduces the size and PI of the primary breast tumor independent of the patient's node status. The PI may be an early means by which to identify tumors most likely to reduce in size with chemotherapy. A low PI after NACT is associated with better survival. There is persistent expression of VEGF in post-NACT residual breast carcinoma. Thus, anti-VEGF drugs after conventional chemotherapy may benefit patients with residual carcinoma.

Single-dose pharmacokinetics of sodium ferric gluconate complex in iron-deficient subjects.

STUDY OBJECTIVES: To determine the single-dose pharmacokinetics of intravenous sodium ferric gluconate complex in sucrose injection (SFGC) in iron-deficient human volunteers, and to assess iron transport. DESIGN: Open-label, randomized study. SETTING: Clinical research facility. SUBJECTS: Fourteen iron-deficient men and women. INTERVENTIONS: Subjects were randomized to receive a single intravenous dose of either SFGC 62.5 mg administered over 30 minutes or SFGC 125 mg over 60 minutes. Five days later, the same subjects were rerandomized to receive a second intravenous dose of SFGC, either 62.5 mg administered over 4 minutes or 125 mg over 7 minutes. MEASUREMENTS AND MAIN RESULTS: Blood samples were collected at predefined times before, during, and up to 72 hours after the infusion to determine the single-dose pharmacokinetics of SFGC. Assays were performed for both total iron and transferrin-bound iron, from which drug-bound iron could be calculated. Urine was collected over 24 hours before dosing and for 24 hours after the start of infusion to determine the renal elimination of iron. Clearance of SFGC from serum was rapid and far exceeded rates reported for iron dextran. Pharmacokinetic parameters were unaffected by dose or infusion rate. Serum iron derived from SFGC did not exceed the binding capacity of transferrin. Serum iron from SFGC became rapidly available (< 24 hrs) as transferrin-bound iron, but only after passage through another compartment, presumably the reticuloendothelial system (RES). At least 80% of the administered iron was transported to bone marrow within 24 hours after infusion. CONCLUSIONS: Iron derived from SFGC appears to be rapidly transferred to a bioavailable iron compartment as transferrin-bound iron after digestion in the RES. At the doses administered in this study, liberation of potentially toxic, free iron was not detectable.

Clinical evaluation of heme iron polypeptide: sustaining a response to rHuEPO in hemodialysis patients.

BACKGROUND: Optimizing iron and recombinant human erythropoietin (rHuEPO) therapy is necessary to achieve target hemoglobin levels and minimize costs as the end-stage renal disease (ESRD) population expands. Oral iron products in patients with ESRD have been largely abandoned, and the safety of intravenous (IV) iron preparations has improved with the introduction of new-generation compounds that have little allergenicity. Recent work suggests oral heme iron may be an effective supplement for hemodialysis (HD) patients because it is absorbed by patients with high ferritin levels, has fewer side effects, and its absorption is stimulated by erythropoietin administration. METHODS: We performed an open, 6-month, prospective evaluation of heme iron in HD patients who had been on maintenance IV iron therapy. IV iron was discontinued and replaced with oral heme iron. Serum iron level, hematocrit (Hct), and erythropoietin and IV iron dose were monitored. RESULTS: During 6 months, 4 of 37 patients (11%) dropped out because of insufficient iron supplementation or intolerance and 5 patients (14%) were dropped because of unrelated complications or protocol violation. A slight reduction in average transferrin saturation (TSAT) was seen early, but reversed, and no significant changes were seen in TSAT or Hct. A significant reduction in average serum ferritin level was seen at months 4 through 6 (P < 0.01). CONCLUSION: During the 6-month study period, heme iron polypeptide successfully replaced IV iron therapy in a majority of HD patients and maintained target Hcts with no concomitant use of IV iron. This treatment was associated with a significant increase in rHuEPO efficiency (P = 0.04).