Safety of antiemetic prophylaxis with HTX-019 as a 30-min infusion in patients with cancer: a retrospective study.

Aim: The NK-1 receptor antagonist HTX-019 (CINVANTI® [aprepitant injectable emulsion]) was approved for preventing chemotherapy-induced nausea and vomiting based on bioequivalence studies in healthy volunteers. The objective of this study was to evaluate HTX-019 safety in cancer patients. Patients & methods: This retrospective analysis evaluated the safety of HTX-019 130 mg 30-min intravenous infusion, as part of a three-drug antiemetic regimen. Results: No treatment-emergent adverse events (TEAEs) were deemed related to HTX-019. During treatment cycles, three of 100 patients developed five reversible TEAEs: dyspnea, hot flash, pain, nausea and visual disturbance. Between cycles, six patients had TEAEs of dizziness (three patients), infusion-site events (two patients) and headache (two patients). Conclusion: HTX-019 is safe in cancer patients receiving chemotherapy.

A Phase I Study of the Hsp90 Inhibitor AUY922 plus Capecitabine for the Treatment of Patients with Advanced Solid Tumors.

BACKGROUND: This phase I study determined the maximum tolerated dose (MTD) of AUY922 with capecitabine in advanced solid tumors. METHODS: Capecitabine 1000 mg/m(2) PO BID was administered with escalating doses of AUY922 IV; the MTD of AUY922 was combined with capecitabine 1250 mg/m(2) (DL6). RESULTS: 23 patients were treated at 5 dose levels (22 mg/m(2)-70 mg/m(2)). No DLTs were observed until DL6 (grade 3 diarrhea). Reversible vision darkening was seen in 26%. Four patients had partial response; 2 previously progressed on fluorouracil. Eight patients had stable disease (median 25.5 weeks). CONCLUSION: AUY922 plus capecitabine was well-tolerated up to 70 mg/m(2) with encouraging preliminary efficacy.

Pseudouridine synthase 1: a site-specific synthase without strict sequence recognition requirements.

Pseudouridine synthase 1 (Pus1p) is an unusual site-specific modification enzyme in that it can modify a number of positions in tRNAs and can recognize several other types of RNA. No consensus recognition sequence or structure has been identified for Pus1p. Human Pus1p was used to determine which structural or sequence elements of human tRNA(Ser) are necessary for pseudouridine (Ψ) formation at position 28 in the anticodon stem-loop (ASL). Some point mutations in the ASL stem of tRNA(Ser) had significant effects on the levels of modification and compensatory mutation, to reform the base pair, restored a wild-type level of Ψ formation. Deletion analysis showed that the tRNA(Ser) TΨC stem-loop was a determinant for modification in the ASL. A mini-substrate composed of the ASL and TΨC stem-loop exhibited significant Ψ formation at position 28 and a number of mutants were tested. Substantial base pairing in the ASL stem (3 out of 5 bp) is required, but the sequence of the TΨC loop is not required for modification. When all nucleotides in the ASL stem other than U28 were changed in a single mutant, but base pairing was retained, a near wild-type level of modification was observed.

A small RNA derived from RNA coactivator SRA blocks steroid receptor signaling via inhibition of Pus1p-mediated pseudouridylation of SRA: evidence of a novel RNA binding domain in the N-terminus of steroid receptors.

Estrogen receptors (ERs) and androgen receptors (ARs) are important targets for cancer therapy; however, the efficacy of receptor antagonists is limited, and alternative strategies are needed. Steroid receptor RNA Activator (SRA) is a long, noncoding RNA coactivator (although some protein-encoding 5' splice variants have also been reported) that requires pseudouridylation by Pus1p to stimulate steroid receptor signaling. A uridine at position 206 (U206), which is located in small hairpin structure STR5 in the conserved SRA core sequence, is a critical target for pseudouridylation. We assessed if synthetic STR5 could serve as a novel competitive inhibitor of ERα and AR signaling by disrupting the Pus1p-SRA-steroid receptor axis. STR5 specifically inhibited Pus1p-dependent pseudouridylation of SRA with higher efficiency than STR5 mutant U206A. We show that SRA binds to the N-terminal domain (NTD) of ERα and AR with high affinity despite the absence of a recognizable RNA binding motif (RBM). Finally, we show that STR5 specifically inhibits ERα- and AR-dependent transactivation of target genes in steroid-sensitive cancer cells, consistent with disruption of the targeted Pus1p-SRA pathway. Together, our results show that the NTD of ERα and AR contains a novel RBM that directly binds SRA, and that STR5 can serve as a novel class of RNA inhibitor of ERα and AR signaling by interfering with Pus1p-mediated SRA pseudouridylation. Targeting this unexplored receptor signaling pathway may pave the way for the development of new types of cancer therapeutics.

Partial activity is seen with many substitutions of highly conserved active site residues in human Pseudouridine synthase 1.

Pseudouridine synthase 1 (Pus1p) is an enzyme that converts uridine to Pseudouridine (Psi) in tRNA and other RNAs in eukaryotes. The active site of Pus1p is composed of stretches of amino acids that are highly conserved and it is hypothesized that mutation of select residues would impair the enzyme's ability to catalyze the formation of Psi. However, most mutagenesis studies have been confined to substitution of the catalytic aspartate, which invariably results in an inactive enzyme in all Psi synthases tested. To determine the requirements for particular amino acids at certain absolutely conserved positions in Pus1p, three residues (R116, Y173, R267) that correspond to amino acids known to compose the active site of TruA, a bacterial Psi synthase that is homologous to Pus1p, were mutated in human Pus1p (hPus1p). The effects of those mutations were determined with three different in vitro assays of pseudouridylation and several tRNA substrates. Surprisingly, it was found that each of these components of the hPus1p active site could tolerate certain amino acid substitutions and in fact most mutants exhibited some activity. The most active mutants retained near wild-type activity at positions 27 or 28 in the substrate tRNA, but activity was greatly reduced or absent at other positions in tRNA readily modified by wild-type hPus1p.

A phase II trial of vinflunine as monotherapy or in combination with trastuzumab as first-line treatment of metastatic breast cancer.

We investigated the microtubulin inhibitor vinflunine­with trastuzumab in human epidermal growth factor receptor-2 (HER2)-positive patients­as first-line metastatic breast cancer therapy. HER2-negative patients received vinflunine on day 1; HER2-positive patients received vinflunine/trastuzumab every 21 days. Forty-eight patients in each treatment group were planned; the sponsor terminated the study early. Thirty-two evaluable patients (vinflunine, 11; vinflunine/trastuzumab, 21) were enrolled. In HER2-positive patients, vinflunine/trastuzumab produced an objective response rate (33%), clinical benefit rate (71%), and progression-free survival (6.2 months). Grade-3/4 neutropenia occurred in 14 (44%) patients; gastrointestinal toxicities were common and six patients were hospitalized for treatment-related toxicity. The vinflunine/trastuzumab combination was active and well tolerated, but our results do not suggest advantages over taxane/trastuzumab or vinorelbine/trastuzumab.

Pus3p- and Pus1p-dependent pseudouridylation of steroid receptor RNA activator controls a functional switch that regulates nuclear receptor signaling.

It was previously shown that mouse Pus1p (mPus1p), a pseudouridine synthase (PUS) known to modify certain transfer RNAs (tRNAs), can also bind with nuclear receptors (NRs) and function as a coactivator through pseudouridylation and likely activation of an RNA coactivator called steroid receptor RNA activator (SRA). Use of cell extract devoid of human Pus1p activity derived from patients with mitochondrial myopathy and sideroblastic anemia, however, still showed SRA-modifying activity suggesting that other PUS(s) can also target this coactivator. Here, we show that related mPus3p, which has a different tRNA specificity than mPus1p, also serves as a NR coactivator. However, in contrast to mPus1p, it does not stimulate sex steroid receptor activity, which is likely due to lack of binding to this class of NRs. As expected from their tRNA activities, in vitro pseudouridylation assays show that mPus3p and mPus1p modify different positions in SRA, although some may be commonly targeted. Interestingly, the order in which these enzymes modify SRA determines the total number of pseudouridines. mPus3p and SRA are mainly cytoplasmic; however, mPus3p and SRA are also localized in distinct nuclear subcompartments. Finally, we identified an in vivo modified position in SRA, U206, which is likely a common target for both mPus1p and mPus3p. When U206 is mutated to A, SRA becomes hyperpseudouridylated in vitro, and it acquires dominant-negative activity in vivo. Thus, Pus1p- and Pus3p-dependent pseudouridylation of SRA is a highly complex posttranscriptional mechanism that controls a coactivator-corepressor switch in SRA with major consequences for NR signaling.

Does site-of-care for oncology infusion therapy influence treatment patterns, cost, and quality in the United States?

BACKGROUND: The increase in hospital acquisition of community oncology clinics in the US has led to a shift in the site-of-care (SOC) for infusion therapy from the physician office (PO) to the hospital outpatient (HO) setting. OBJECTIVE: To investigate differences by SOC in treatment patterns, quality, and cost among patients with cancer undergoing first-line infusion therapy. RESEARCH DESIGN AND METHODS: This retrospective analysis identified adult patients from Humana medical claims who initiated infusion therapy from 2008-2012 for five common cancer types in which infusion therapy is likely, including early stage breast cancer; metastatic breast, lung, and colorectal cancers; and non-Hodgkin's lymphoma or chronic lymphocytic leukemia. Differences by SOC in first-line treatment patterns and quality of care at end-of-life, defined as infusions or hospitalizations 30 days prior to death, were evaluated using Wilcoxon-Rank Sum and Chi-square tests where appropriate. Differences in cost by SOC were evaluated using risk-adjusted generalized linear models. MAIN OUTCOME MEASURES: Treatment patterns, quality of care at end of life, healthcare costs. RESULTS: There were differences in duration of therapy and number of infusions for some therapy regimens by SOC, in which patients in the HO had shorter duration of therapy and fewer infusions. There were no differences in quality of care at end-of-life by SOC. Total healthcare costs were 15% higher among patients in HO ($55,965) compared with PO ($48,439), p < .0001. LIMITATIONS: Analyses was restricted to a claims-based population of cancer patients within a health plan. CONCLUSION: This study, in an older, predominantly Medicare Advantage oncology cohort, found differences by SOC in treatment patterns and cost, but not quality. Where differences were found, patients receiving care in the HO had shorter duration of therapy and fewer infusions for specific treatment regimens, but higher healthcare costs than those treated in a PO.

Pseudouridine synthase 1 deficient mice, a model for Mitochondrial Myopathy with Sideroblastic Anemia, exhibit muscle morphology and physiology alterations.

Mitochondrial myopathy with lactic acidosis and sideroblastic anemia (MLASA) is an oxidative phosphorylation disorder, with primary clinical manifestations of myopathic exercise intolerance and a macrocytic sideroblastic anemia. One cause of MLASA is recessive mutations in PUS1, which encodes pseudouridine (Ψ) synthase 1 (Pus1p). Here we describe a mouse model of MLASA due to mutations in PUS1. As expected, certain Ψ modifications were missing in cytoplasmic and mitochondrial tRNAs from Pus1(-/-) animals. Pus1(-/-) mice were born at the expected Mendelian frequency and were non-dysmorphic. At 14 weeks the mutants displayed reduced exercise capacity. Examination of tibialis anterior (TA) muscle morphology and histochemistry demonstrated an increase in the cross sectional area and proportion of myosin heavy chain (MHC) IIB and low succinate dehydrogenase (SDH) expressing myofibers, without a change in the size of MHC IIA positive or high SDH myofibers. Cytochrome c oxidase activity was significantly reduced in extracts from red gastrocnemius muscle from Pus1(-/-) mice. Transmission electron microscopy on red gastrocnemius muscle demonstrated that Pus1(-/-) mice also had lower intermyofibrillar mitochondrial density and smaller mitochondria. Collectively, these results suggest that alterations in muscle metabolism related to mitochondrial content and oxidative capacity may account for the reduced exercise capacity in Pus1(-/-) mice.

Pseudouridine modification in Caenorhabditis elegans spliceosomal snRNAs: unique modifications are found in regions involved in snRNA-snRNA interactions.

BACKGROUND: Pseudouridine (Psi) is an abundant modified nucleoside in RNA and a number of studies have shown that the presence of Psi affects RNA structure and function. The positions of Psi in spliceosomal small nuclear RNAs (snRNAs) have been determined for a number of species but not for the snRNAs from Caenorhabditis elegans (C. elegans), a popular experimental model system of development. RESULTS: As a prelude to determining the function of or requirement for this modification in snRNAs, we have mapped the positions of Psi in U1, U2, U4, U5, and U6 snRNAs from worms using a specific primer extension method. As with other species, C. elegans U2 snRNA has the greatest number of Psi residues, with nine, located in the 5' half of the U2 snRNA. U5 snRNA has three Psis, in or near the loop of the large stem-loop that dominates the structure of this RNA. U6 and U1 snRNAs each have one Psi, and two Psi residues were found in U4 snRNA. CONCLUSION: The total number of Psis found in the snRNAs of C. elegans is significantly higher than the minimal amount found in yeasts but it is lower than that seen in sequenced vertebrate snRNAs. When the actual sites of modification on C. elegans snRNAs are compared with other sequenced snRNAs most of the positions correspond to modifications found in other species. However, two of the positions modified on C. elegans snRNAs are unique, one at position 28 on U2 snRNA and one at position 62 on U4 snRNA. Both of these modifications are in regions of these snRNAs that interact with U6 snRNA either in the spliceosome or in the U4/U6 small nuclear ribonucleoprotein particle (snRNP) and the presence of Psi may be involved in strengthening the intermolecular association of the snRNAs.

A retrospective cohort study to assess the impact of therapeutic substitution of darbepoetin alfa for epoetin alfa in anemic patients with myelodysplastic syndrome.

Darbepoetin alfa and epoetin alfa are used to treat anemia in the undertreated population of patients with myelodysplastic syndrome (MDS). We implemented guidelines to switch anemic patients with MDS from epoetin alfa 40,000 U weekly to darbepoetin alfa 200 microg every 2 weeks and then conducted a retrospective cohort study of the initial 263 treated patients. Patients (> or = 18 years old, MDS diagnosis) were either previously treated with epoetin alfa (received 16 weeks of prior epoetin alfa and either switched to darbepoetin alfa or remained on epoetin alfa) or treatment-naive (no previous erythropoietin therapy and received only 1 agent for 16 weeks). Both major response and minor response based on the International Working Group criteria were calculated. The study was not powered to statistically compare treatment groups; values presented are for descriptive purposes only. Data from 244 patient records were included: 142 previous epoetin alfa patients (80 switched to darbepoetin alfa, 62 remained on epoetin alfa) and 102 naive patients (56 darbepoetin alfa, 46 epoetin alfa). Major response rates were similar between treatment groups in both the naive (46% for darbepoetin alfa, 35% for epoetin alfa) and previous epoetin alfa groups (26% for darbepoetin alfa, 17% for epoetin alfa). Overall response rates were 42%-76% across treatment groups. No differences in transfusions across groups were observed. Treatment of anemic patients with MDS with either darbepoetin alfa or epoetin alfa appeared to be effective. Whereas epoetin alfa was most frequently administered on a weekly basis, darbepoetin alfa was most frequently administered every 2 weeks, which may offer the benefit of convenience with its less frequent dosing.

a-Stratified Computerized Adaptive Testing in the Presence of Calibration Error.

a-Stratified computerized adaptive testing with b-blocking (AST), as an alternative to the widely used maximum Fisher information (MFI) item selection method, can effectively balance item pool usage while providing accurate latent trait estimates in computerized adaptive testing (CAT). However, previous comparisons of these methods have treated item parameter estimates as if they are the true population parameter values. Consequently, capitalization on chance may occur. In this article, we examined the performance of the AST method under more realistic conditions where item parameter estimates instead of true parameter values are used in the CAT. Its performance was compared against that of the MFI method when the latter is used in conjunction with Sympson-Hetter or randomesque exposure control. Results indicate that the MFI method, even when combined with exposure control, is susceptible to capitalization on chance. This is particularly true when the calibration sample size is small. On the other hand, AST is more robust to capitalization on chance. Consistent with previous investigations using true item parameter values, AST yields much more balanced item pool usage, with a small loss in the precision of latent trait estimates. The loss is negligible when the test is as long as 40 items.

Steroid receptor RNA activator (SRA) modification by the human pseudouridine synthase 1 (hPus1p): RNA binding, activity, and atomic model.

The most abundant of the modified nucleosides, and once considered as the "fifth" nucleotide in RNA, is pseudouridine, which results from the action of pseudouridine synthases. Recently, the mammalian pseudouridine synthase 1 (hPus1p) has been reported to modulate class I and class II nuclear receptor responses through its ability to modify the Steroid receptor RNA Activator (SRA). These findings highlight a new level of regulation in nuclear receptor (NR)-mediated transcriptional responses. We have characterised the RNA association and activity of the human Pus1p enzyme with its unusual SRA substrate. We validate that the minimal RNA fragment within SRA, named H7, is necessary for both the association and modification by hPus1p. Furthermore, we have determined the crystal structure of the catalytic domain of hPus1p at 2.0 Å resolution, alone and in a complex with several molecules present during crystallisation. This model shows an extended C-terminal helix specifically found in the eukaryotic protein, which may prevent the enzyme from forming a homodimer, both in the crystal lattice and in solution. Our biochemical and structural data help to understand the hPus1p active site architecture, and detail its particular requirements with regard to one of its nuclear substrates, the non-coding RNA SRA.

Phase II study of biweekly pemetrexed and gemcitabine in patients with previously untreated advanced non-small cell lung cancer.

INTRODUCTION: Pemetrexed and gemcitabine are safe and active non-small cell lung cancer (NSCLC) therapies when administered every 3 weeks. Biweekly scheduling was studied in this phase II trial. METHODS: The primary objective was to assess the overall response rate in chemotherapy-naive patients with unresectable stage III/IV NSCLC. Patients received 500 mg/m(2) of pemetrexed intravenously and 1500 mg/m(2) of gemcitabine intravenously every 2 weeks for 8 to 12 cycles with restaging every 4 cycles. Patients also received supplemental folate/B12 therapy. Entry criteria included the following: all non-small cell histologies, measurable disease, Eastern Cooperative Oncology Group 0 to 2, and informed consent. RESULTS: Seventy-two patients were enrolled. Baseline characteristics included the following: median age: 66 years (41-85 years); male/female: 65%/35%; Eastern Cooperative Oncology Group 0/1/2: 19%/67%/14%; and histology: adenocarcinoma (36%), large cell (18%), squamous (13%), and mixed or not specified (34%). The median number of cycles was 7 (range, 1-12). The most common (> or =5%) grade 3/4 toxicities were as follows: neutropenia (47%), leukopenia (31%), fatigue (25%), dyspnea (18%), pain (11%), and anemia (8%). Complete/partial responses for all patients: 1 patient/18 patients, respectively, for an overall response rate of 26% (95% confidence interval, 17-38%). Thirty-nine percentage of patients had stable disease, and 21% had disease progression (10 patients were not evaluable). Median progression-free survival was 6.2 months. One-year overall survival was 37.5%. CONCLUSION: Biweekly administration of pemetrexed and gemcitabine seems to be well tolerated with activity comparable with other first-line NSCLC regimens. Further study addressing whether biweekly scheduling could be an effective strategy to shorten overall treatment duration will require a randomized design.

Tracheoesophageal fistula formation in patients with lung cancer treated with chemoradiation and bevacizumab.

PURPOSE Tracheoesophageal fistulae are rare complications of thoracic cancers and their treatments. Novel antiangiogenic agents in cancer treatment such as bevacizumab potentially impact wound healing and may contribute to tracheoesophageal fistula development. PATIENTS AND METHODS We conducted two independent phase II clinical trials in small-cell lung cancer and non-small-cell lung cancer using bevacizumab in combination with chemotherapy and radiation. Both trials were intended to assess preliminary efficacy and safety outcomes. Results For the limited-stage small-cell lung cancer trial, 29 patients were enrolled beginning April 2006, and closed early due to toxicity in March 2007 (14-month median follow-up). The locally advanced, non-small-cell lung cancer trial opened with enrollment limited to five patients in February 2007, and closed early due to safety in December 2007. In each trial, we observed tracheoesophageal fistulae development and related morbidity and mortality, prompting early trial closures, US Food and Drug Administration warnings, and a change in bevacizumab labeling. CONCLUSION The current data from the final reports from these two trials suggest bevacizumab and chemoradiotherapy are associated with a relatively high incidence of tracheoesophageal fistulae formation in both small-cell lung cancer and non-small-cell lung cancer settings. Strategies to safely incorporate novel antiangiogenic agents into combined-modality therapy in lung cancer are needed.

A previously unidentified activity of yeast and mouse RNA:pseudouridine synthases 1 (Pus1p) on tRNAs.

Mouse pseudouridine synthase 1 (mPus1p) was the first vertebrate RNA:pseudouridine synthase that was cloned and characterized biochemically. The mPus1p was previously found to catalyze Psi formation at positions 27, 28, 34, and 36 in in vitro produced yeast and human tRNAs. On the other hand, the homologous Saccharomyces cerevisiae scPus1p protein was shown to modify seven uridine residues in tRNAs (26, 27, 28, 34, 36, 65, and 67) and U44 in U2 snRNA. In this work, we expressed mPus1p in yeast cells lacking scPus1p and studied modification of U2 snRNA and several yeast tRNAs. Our data showed that, in these in vivo conditions, the mouse enzyme efficiently modifies yeast U2 snRNA at position 44 and tRNAs at positions 27, 28, 34, and 36. However, a tRNA:Psi26-synthase activity of mPus1p was not observed. Furthermore, we found that both scPus1p and mPus1p, in vivo and in vitro, have a previously unidentified activity at position 1 in cytoplasmic tRNAArg(ACG). This modification can take place in mature tRNA, as well as in pre-tRNAs with 5' and/or 3' extensions. Thus, we identified the protein carrying one of the last missing yeast tRNA:Psi synthase activities. In addition, our results reveal an additional activity of mPus1p at position 30 in tRNA that scPus1p does not possess.

Mitochondrial myopathy and sideroblastic anemia (MLASA): missense mutation in the pseudouridine synthase 1 (PUS1) gene is associated with the loss of tRNA pseudouridylation.

A missense mutation in the PUS1 gene affecting a highly conserved amino acid has been associated with mitochondrial myopathy and sideroblastic anemia (MLASA), a rare autosomal recessive oxidative phosphorylation disorder. The PUS1 gene encodes the enzyme pseudouridine synthase 1 (Pus1p) that is known to pseudouridylate tRNAs in other species. Total RNA was isolated from lymphoblastoid cell lines established from patients, parents, unaffected siblings, and unrelated controls, and the tRNAs were assayed for the presence of pseudouridine (Psi) at the expected positions. Mitochondrial and cytoplasmic tRNAs from MLASA patients are lacking modification at sites normally modified by Pus1p, whereas tRNAs from controls, unaffected siblings, or parents all have Psi at these positions. In addition, there was no Pus1p activity in an extract made from a cell line derived from a patient with MLASA. Immunohistochemical staining of Pus1p in cell lines showed nuclear, cytoplasmic, and mitochondrial distribution of the protein, and there is no difference in staining between patients and unaffected family members. MLASA is thus associated with absent or greatly reduced tRNA pseudouridylation at specific sites, implicating this pathway in its molecular pathogenesis.

Caenorhabditis elegans pseudouridine synthase 1 activity in vivo: tRNA is a substrate, but not U2 small nuclear RNA.

The formation of pseudouridine (Psi) from uridine is post-transcriptional and catalysed by pseudouridine synthases, several of which have been characterized from eukaryotes. Pseudouridine synthase 1 (Pus1p) has been well characterized from yeast and mice. In yeast, Pus1p has been shown to have dual substrate specificity, modifying uridines in tRNAs and at position 44 in U2 small nuclear RNA (U2 snRNA). In order to study the in vivo activity of a metazoan Pus1p, a knockout of the gene coding for the homologue of Pus1p in Caenorhabditis elegans was obtained. The deletion encompasses the first two putative exons and includes the essential aspartate that is required for activity in truA pseudouridine synthases. The locations of most modified nucleotides on small RNAs in C. elegans are not known, and the positions of Psi were determined on four tRNAs and U2 snRNA. The uridine at position 27 of tRNA(Val) (AAC), a putative Pus1p-modification site, was converted into Psi in the wild-type worms, but the tRNA(Val) (AAC) from mutant worms lacked the modification. Psi formation at positions 13, 32, 38 and 39, all of which should be modified by other pseudouridine synthases, was not affected by the loss of Pus1p. The absence of Pus1p in C. elegans had no effect on the modification of U2 snRNA in vivo, even though worm U2 snRNA has a Psi at position 45 (the equivalent of yeast U2 snRNA position 44) and at four other positions. This result was unexpected, given the known dual specificity of yeast Pus1p.