Superfluorescence from lead halide perovskite quantum dot superlattices.

An ensemble of emitters can behave very differently from its individual constituents when they interact coherently via a common light field. After excitation of such an ensemble, collective coupling can give rise to a many-body quantum phenomenon that results in short, intense bursts of light-so-called superfluorescence1. Because this phenomenon requires a fine balance of interactions between the emitters and their decoupling from the environment, together with close identity of the individual emitters, superfluorescence has thus far been observed only in a limited number of systems, such as certain atomic and molecular gases and a few solid-state systems2-7. The generation of superfluorescent light in colloidal nanocrystals (which are bright photonic sources practically suited for optoelectronics8,9) has been precluded by inhomogeneous emission broadening, low oscillator strength, and fast exciton dephasing. Here we show that caesium lead halide (CsPbX3, X = Cl, Br) perovskite nanocrystals10-13 that are self-organized into highly ordered three-dimensional superlattices exhibit key signatures of superfluorescence. These are dynamically red-shifted emission with more than 20-fold accelerated radiative decay, extension of the first-order coherence time by more than a factor of four, photon bunching, and delayed emission pulses with Burnham-Chiao ringing behaviour14 at high excitation density. These mesoscopically extended coherent states could be used to boost the performance of opto-electronic devices15 and enable entangled multi-photon quantum light sources16,17.

Bright triplet excitons in caesium lead halide perovskites.

Nanostructured semiconductors emit light from electronic states known as excitons. For organic materials, Hund's rules state that the lowest-energy exciton is a poorly emitting triplet state. For inorganic semiconductors, similar rules predict an analogue of this triplet state known as the 'dark exciton'. Because dark excitons release photons slowly, hindering emission from inorganic nanostructures, materials that disobey these rules have been sought. However, despite considerable experimental and theoretical efforts, no inorganic semiconductors have been identified in which the lowest exciton is bright. Here we show that the lowest exciton in caesium lead halide perovskites (CsPbX3, with X = Cl, Br or I) involves a highly emissive triplet state. We first use an effective-mass model and group theory to demonstrate the possibility of such a state existing, which can occur when the strong spin-orbit coupling in the conduction band of a perovskite is combined with the Rashba effect. We then apply our model to CsPbX3 nanocrystals, and measure size- and composition-dependent fluorescence at the single-nanocrystal level. The bright triplet character of the lowest exciton explains the anomalous photon-emission rates of these materials, which emit about 20 and 1,000 times faster than any other semiconductor nanocrystal at room and cryogenic temperatures, respectively. The existence of this bright triplet exciton is further confirmed by analysis of the fine structure in low-temperature fluorescence spectra. For semiconductor nanocrystals, which are already used in lighting, lasers and displays, these excitons could lead to materials with brighter emission. More generally, our results provide criteria for identifying other semiconductors that exhibit bright excitons, with potential implications for optoelectronic devices.

Cardiovascular Safety of Febuxostat or Allopurinol in Patients with Gout.

BACKGROUND: Cardiovascular risk is increased in patients with gout. We compared cardiovascular outcomes associated with febuxostat, a nonpurine xanthine oxidase inhibitor, with those associated with allopurinol, a purine base analogue xanthine oxidase inhibitor, in patients with gout and cardiovascular disease. METHODS: We conducted a multicenter, double-blind, noninferiority trial involving patients with gout and cardiovascular disease; patients were randomly assigned to receive febuxostat or allopurinol and were stratified according to kidney function. The trial had a prespecified noninferiority margin of 1.3 for the hazard ratio for the primary end point (a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or unstable angina with urgent revascularization). RESULTS: In total, 6190 patients underwent randomization, received febuxostat or allopurinol, and were followed for a median of 32 months (maximum, 85 months). The trial regimen was discontinued in 56.6% of patients, and 45.0% discontinued follow-up. In the modified intention-to-treat analysis, a primary end-point event occurred in 335 patients (10.8%) in the febuxostat group and in 321 patients (10.4%) in the allopurinol group (hazard ratio, 1.03; upper limit of the one-sided 98.5% confidence interval [CI], 1.23; P=0.002 for noninferiority). All-cause and cardiovascular mortality were higher in the febuxostat group than in the allopurinol group (hazard ratio for death from any cause, 1.22 [95% CI, 1.01 to 1.47]; hazard ratio for cardiovascular death, 1.34 [95% CI, 1.03 to 1.73]). The results with regard to the primary end point and all-cause and cardiovascular mortality in the analysis of events that occurred while patients were being treated were similar to the results in the modified intention-to-treat analysis. CONCLUSIONS: In patients with gout and major cardiovascular coexisting conditions, febuxostat was noninferior to allopurinol with respect to rates of adverse cardiovascular events. All-cause mortality and cardiovascular mortality were higher with febuxostat than with allopurinol. (Funded by Takeda Development Center Americas; CARES ClinicalTrials.gov number, NCT01101035 .).

Trion Emission Dominates the Low-Temperature Photoluminescence of CdSe Nanoplatelets.

Colloidal nanoplatelets (NPLs) are atomically flat, quasi-two-dimensional particles of a semiconductor. Despite intense interest in their optical properties, several observations concerning the emission of CdSe NPLs remain puzzling. While their ensemble photoluminescence spectrum consists of a single narrow peak at room temperature, two distinct emission features appear at temperatures below ∼160 K. Several competing explanations for the origin of this two-color emission have been proposed. Here, we present temperature- and time-dependent experiments demonstrating that the two emission colors are due to two subpopulations of uncharged and charged NPLs. We study dilute films of isolated NPLs, thus excluding any explanation relying on collective effects due to NPL stacking. Temperature-dependent measurements explain that trion emission from charged NPLs is bright at cryogenic temperatures, while temperature activation of nonradiative Auger recombination quenches the trion emission above 160 K. Our findings clarify many of the questions surrounding the photoluminescence of CdSe NPLs.

Long Exciton Dephasing Time and Coherent Phonon Coupling in CsPbBr2Cl Perovskite Nanocrystals.

Fully inorganic cesium lead halide perovskite nanocrystals (NCs) have shown to exhibit outstanding optical properties such as wide spectral tunability, high quantum yield, high oscillator strength as well as blinking-free single photon emission, and low spectral diffusion. Here, we report measurements of the coherent and incoherent exciton dynamics on the 100 fs to 10 ns time scale, determining dephasing and density decay rates in these NCs. The experiments are performed on CsPbBr2Cl NCs using transient resonant three-pulse four-wave mixing (FWM) in heterodyne detection at temperatures ranging from 5 to 50 K. We found a low-temperature exciton dephasing time of 24.5 ± 1.0 ps, inferred from the decay of the photon-echo amplitude at 5 K, corresponding to a homogeneous line width (fwhm) of 54 ± 5 µeV. Furthermore, oscillations in the photon-echo signal on a picosecond time scale are observed and attributed to coherent coupling of the exciton to a quantized phonon mode with 3.45 meV energy.

Infusion-related reactions with pegloticase, a recombinant uricase for the treatment of chronic gout refractory to conventional therapy.

BACKGROUND: In clinical trials of pegloticase, a PEGylated uricase developed for treatment of gout refractory to conventional therapy, infusion-related reactions (IRs) were the second most frequent adverse event reported. OBJECTIVE: The objective of this study was to provide a detailed account of IRs with pegloticase therapy. METHODS: Data from 2 replicate, 6-month randomized trials and an open-label extension study were pooled. Infusions of pegloticase (8 mg) were administered biweekly or monthly; all patients received prophylaxis (antihistamine, acetaminophen, and corticosteroid) and were tested for urate levels prior to each infusion. An IR was defined by protocol as any otherwise unexplained adverse event or cluster of temporally related events occurring during or within 2 hours of infusion. RESULTS: Infusion-related reactions occurred in 94 (45%) of 208 patients receiving pegloticase; 10 patients reported IRs at first infusion and 84 during subsequent infusions. Chest discomfort (15%), flushing (12%), and dyspnea (11%) were the most common symptoms. Most IRs were rated mild or moderate; 7% were rated severe. All IRs resolved with slowing, interrupting, or stopping the infusion. No patient required blood pressure or ventilatory support. Infusion-related reactions were associated with loss of pegloticase urate-lowering efficacy: 91% of all IRs occurred in patients with preinfusion serum uric acid concentrations (sUA) greater than 6 mg/dL. For patients sustaining preinfusion sUA of less than 6 mg/dL, IRs occurred in fewer than 1 per 100 infusions. CONCLUSIONS: Phase 3 trial data combined with post hoc analyses demonstrated that knowledge of sUA preceding each pegloticase infusion and cessation of therapy when urate-lowering efficacy is lost provide a means to optimize the safety of pegloticase in clinical practice.

Circularly Polarized Luminescence Without External Magnetic Fields from Individual CsPbBr3 Perovskite Quantum Dots.

Lead halide perovskite quantum dots (QDs), the latest generation of the colloidal QD family, exhibit outstanding optical properties, which are now exploited as both classical and quantum light sources. Most of their rather exceptional properties are related to the peculiar exciton fine-structure of band-edge states, which can support unique bright triplet excitons. The degeneracy of the bright triplet excitons is lifted with energetic splitting in the order of millielectronvolts, which can be resolved by the photoluminescence (PL) measurements of single QDs at cryogenic temperatures. Each bright exciton fine-structure-state (FSS) exhibits a dominantly linear polarization, in line with several theoretical models based on the sole crystal field, exchange interaction, and shape anisotropy. Here, we show that in addition to a high degree of linear polarization, the individual exciton FSS can exhibit a non-negligible degree of circular polarization even without external magnetic fields by investigating the four Stokes parameters of the exciton fine-structure in individual CsPbBr3 QDs through Stokes polarimetric measurements. We observe a degree of circular polarization up to ∼38%, which could not be detected by using the conventional polarimetric technique. In addition, we found a consistent transition from left- to right-hand circular polarization within the fine-structure triplet manifold, which was observed in magnetic-field-dependent experiments. Our optical investigation provides deeper insights into the nature of the exciton fine structures and thereby drives the yet-incomplete understanding of the unique photophysical properties of this class of QDs for the benefit of future applications in chiral quantum optics.

Long-term safety of pegloticase in chronic gout refractory to conventional treatment.

OBJECTIVE: To evaluate the long-term safety (up to 3 years) of treatment with pegloticase in patients with refractory chronic gout. METHODS: This open-label extension (OLE) study was conducted at 46 sites in the USA, Canada and Mexico. Patients completing either of two replicate randomised placebo-controlled 6-month trials received pegloticase 8 mg every 2 weeks (biweekly) or every 4 weeks (monthly). Safety was evaluated as the primary outcome, with special interest in gout flares and infusion-related reactions (IRs). Secondary outcomes included urate-lowering and clinical efficacy. RESULTS: Patients (n=149) received a mean±SD of 28±18 pegloticase infusions and were followed for a mean of 25±11 months. Gout flares and IRs were the most frequently reported adverse events; these were least common in patients with a sustained urate-lowering response to treatment and those receiving biweekly treatment. In 10 of the 11 patients with a serious IR, the event occurred when uric acid exceeded 6 mg/dl. Plasma and serum uric acid levels remained <6 mg/dl in most randomised controlled trial (RCT)-defined pegloticase responders throughout the OLE study and were accompanied by sustained and progressive improvements in tophus resolution and flare incidence. CONCLUSIONS: The safety profile of long-term pegloticase treatment was consistent with that observed during 6 months of RCT treatment; no new safety signals were identified. Improvements in clinical status, in the form of flare and tophus reduction initiated during RCT pegloticase treatment in patients maintaining goal range urate-lowering responses were sustained or advanced during up to 2.5 years of additional treatment.

A revised estimate of the burden of illness of gout.

BACKGROUND: Gout is a chronic, inflammatory arthritis characterized by painful and debilitating acute/episodic flares. Until recently, gout has been regarded as a minor medical problem, in part because the associated economic burden has not been appreciated. Previous literature on this subject focused on the costs associated with acute episodes of gout rather than on the long-term medical and economic implications of this chronic disorder. OBJECTIVE: Our aim was to estimate the current impact of gout in the United States with respect to disability and economic costs. METHODS: THE FOLLOWING DATA SOURCES WERE USED: published data on the incremental economic burden of gout; statistics from the US Census Bureau and the US Bureau of Labor Statistics; and recent epidemiological and clinical literature concerning the course, treatment, and outcomes of the disease. Disability is expressed as days of lost productivity. Charges for gout-related treatments were used as direct cost inputs. RESULTS: Gout affects an estimated 8 million Americans, among whom those working have an average of almost 5 more absence days annually than workers without gout. On average, the incremental annual cost of care for a gout patient is estimated at >$3000 compared with a nongouty individual. Even though comorbidities common in gout patients account for a portion of this increased economic burden, the total annual cost attributable to gout patients in the United States is likely in the tens of billions of dollars and comparable to those of other major chronic disorders, such as migraine and Parkinson's disease. CONCLUSIONS: The economic burden of gout is most readily assessable in patients whose acute arthritic flares result in emergency department visits, bedridden days, and episodic loss of productivity. Chronic progression of the disease can also result in long-term impairment of function and health-related quality of life, but the contribution of chronic gout to the economic burden is more difficult to quantitate because gout is frequently associated with serious cardiovascular, metabolic, and renal comorbidities. Recent demonstration that successful gout management can reverse functional deficits in many chronic gout patients, however, supports the views that chronic gout contributes substantially to the medical and thus economic costs of these patients and that early and aggressive efforts to improve gout outcomes are likely to reduce the associated economic burden.

Robust Tipless Positioning Device for Near-Field Investigations: Press and Roll Scan (PROscan).

Scanning probe microscopes scan and manipulate a sharp tip in the immediate vicinity of a sample surface. The limited bandwidth of the feedback mechanism used for stabilizing the separation between the tip and the sample makes the fragile nanoscopic tip very susceptible to mechanical instabilities. We propose, demonstrate, and characterize an alternative device based on bulging a thin substrate against a second substrate and rolling them with respect to each other. We showcase the power of this method by placing gold nanoparticles and semiconductor quantum dots on the two opposite substrates and positioning them with nanometer precision to enhance the fluorescence intensity and emission rate. Furthermore, we exhibit the passive mechanical stability of the system over more than 1 h. Our design concept finds applications in a variety of other scientific and technological contexts, where nanoscopic features have to be positioned and kept near contact with each other.

Evaluation of the Relationship Between Serum Urate Levels, Clinical Manifestations of Gout, and Death From Cardiovascular Causes in Patients Receiving Febuxostat or Allopurinol in an Outcomes Trial.

OBJECTIVE: To investigate whether serum urate levels, number of gout flares, and tophi burden are related to death from cardiovascular (CV) causes after treatment with febuxostat or allopurinol in patients with gout from the Cardiovascular Safety of Febuxostat or Allopurinol in Patients With Gout and Cardiovascular Comorbidities (CARES) trial. METHODS: Patients were randomly assigned to receive febuxostat (40 mg or 80 mg once daily, according to serum urate levels at week 2) or allopurinol titrated in 100-mg increments from 200-400 mg or 300-600 mg (with dose determined according to kidney function). Changes from baseline in serum urate level, gout flares, and tophus resolution were key exploratory efficacy parameters in the overall population and in subgroups of patients who died and those who did not die from a CV-related cause. The latter subgroup included patients who died due to non-CV causes and those who did not die due to any cause. RESULTS: Patients received treatment with febuxostat (n = 3,098) or allopurinol (n = 3,092) for a median follow-up period of 32 months (for a maximum of 85 months). In the overall population, mean serum urate levels were lower in those receiving febuxostat compared with those receiving allopurinol at most study visits. There were no associations between serum urate levels and death from CV causes with febuxostat. The number of gout flares requiring treatment was higher within 1 year of treatment with febuxostat compared with allopurinol (mean incidence of gout flares per patient-years of exposure 1.33 versus 1.20), but was comparable thereafter and decreased overall throughout the study period (mean incidence of gout flares per patient-years of exposure 0.35 versus 0.34 after 1 year of treatment; overall mean incidence 0.68 versus 0.63) irrespective of whether the patient died from a CV-related cause. Overall, 20.8% of patients had ≥1 tophus at baseline; tophus resolution rates were similar between treatment groups, with cumulative resolution rates of >50%. CONCLUSION: In the CARES trial, febuxostat and allopurinol (≤600 mg doses) had comparable efficacy in patients with gout and CV disease, and there was no evidence of a relationship between death from CV causes and serum urate levels, number of gout flares, or tophus resolution among the patients receiving febuxostat.

Efficacy and tolerability of pegloticase for the treatment of chronic gout in patients refractory to conventional treatment: two randomized controlled trials.

CONTEXT: Patients with chronic disabling gout refractory to conventional urate-lowering therapy need timely treatment to control disease manifestations related to tissue urate crystal deposition. Pegloticase, monomethoxypoly(ethylene glycol)-conjugated mammalian recombinant uricase, was developed to fulfill this need. OBJECTIVE: To assess the efficacy and tolerability of pegloticase in managing refractory chronic gout. DESIGN, SETTING, AND PATIENTS: Two replicate, randomized, double-blind, placebo-controlled trials (C0405 and C0406) were conducted between June 2006 and October 2007 at 56 rheumatology practices in the United States, Canada, and Mexico in patients with severe gout, allopurinol intolerance or refractoriness, and serum uric acid concentration of 8.0 mg/dL or greater. A total of 225 patients participated: 109 in trial C0405 and 116 in trial C0406. INTERVENTION: Twelve biweekly intravenous infusions containing either pegloticase 8 mg at each infusion (biweekly treatment group), pegloticase alternating with placebo at successive infusions (monthly treatment group), or placebo (placebo group). MAIN OUTCOME MEASURE: Primary end point was plasma uric acid levels of less than 6.0 mg/dL in months 3 and 6. RESULTS: In trial C0405 the primary end point was reached in 20 of 43 patients in the biweekly group (47%; 95% CI, 31%-62%), 8 of 41 patients in the monthly group (20%; 95% CI, 9%-35%), and in 0 patients treated with placebo (0/20; 95% CI, 0%-17%; P < .001 and <.04 for comparisons between biweekly and monthly groups vs placebo, respectively). Among patients treated with pegloticase in trial C0406, 16 of 42 in the biweekly group (38%; 95% CI, 24%-54%) and 21 of 43 in the monthly group (49%; 95% CI, 33%-65%) achieved the primary end point; no placebo-treated patients reached the primary end point (0/23; 95% CI, 0%-15%; P = .001 and < .001, respectively). When data in the 2 trials were pooled, the primary end point was achieved in 36 of 85 patients in the biweekly group (42%; 95% CI, 32%-54%), 29 of 84 patients in the monthly group (35%; 95% CI, 24%-46%), and 0 of 43 patients in the placebo group (0%; 95% CI, 0%-8%; P < .001 for each comparison). Seven deaths (4 in patients receiving pegloticase and 3 in the placebo group) occurred between randomization and closure of the study database (February 15, 2008). CONCLUSION: Among patients with chronic gout, elevated serum uric acid level, and allopurinol intolerance or refractoriness, the use of pegloticase 8 mg either every 2 weeks or every 4 weeks for 6 months resulted in lower uric acid levels compared with placebo. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00325195.

Unraveling the Origin of the Long Fluorescence Decay Component of Cesium Lead Halide Perovskite Nanocrystals.

A common signature of nearly all nanoscale emitters is fluorescence intermittency, which is a rapid switching between "on"-states exhibiting a high photon emission rate and "off"-states with a much lower rate. One consequence of fluorescence intermittency occurring on time scales longer than the exciton decay time is the so-called delayed photon emission, manifested by a long radiative decay component. Besides their dominant fast radiative decay, fully inorganic cesium lead halide perovskite quantum dots exhibit a long fluorescence decay component at cryogenic temperatures that is often attributed to the decay of the dark exciton. Here, we show that its origin is delayed photon emission by investigating temporal variations in fluorescence intensity and concomitant decay times found in single CsPbBr3 perovskite quantum dots. We attribute the different intensity levels of the intensity trace to a rapid switching between a high-intensity exciton state and an Auger-reduced low-intensity trion state that occurs when the excitation is sufficiently strong. Surprisingly, we observe that the exponent of this power-law-dependent delayed emission is correlated with the emission intensity, which cannot be explained with existing charge carrier trapping models. Our analysis reveals that the long decay component is mainly governed by delayed emission, which is present in both the exciton and trion state. The absence of a fine structure in trions clarifies the vanishing role of the dark exciton state for the long decay component. Our findings are essential for the development of a complete photophysical model that captures all observed features of fluorescence variations in colloidal nanocrystals.

Update on emerging urate-lowering therapies.

PURPOSE OF REVIEW: To discuss currently available urate-lowering therapeutic options for gout in the United States and newer therapeutic initiatives in development. RECENT FINDINGS: Currently available urate-lowering drugs include allopurinol and probenecid. These drugs are effective but are often underdosed or underutilized, and caution must be taken in patients with multiple comorbidities. Newer therapeutic agents in development include febuxostat, a nonpurine analogue xanthine oxidase inhibitor, and pegloticase, a pegylated recombinant uricase. SUMMARY: There have been no new US Food and Drug Administration-approved urate-lowering drugs for gout in the past 40 years. Recent advances in therapeutics promise to provide the opportunity for much needed improvement in patient outcomes in this disorder.

Reduction of plasma urate levels following treatment with multiple doses of pegloticase (polyethylene glycol-conjugated uricase) in patients with treatment-failure gout: results of a phase II randomized study.

OBJECTIVE: To assess the efficacy of pegloticase in achieving and maintaining plasma urate levels of <6 mg/dl in gout patients in whom other treatments have failed, and to assess the pharmacokinetics and safety of pegloticase. METHODS: Forty-one patients were randomized to undergo 12-14 weeks of treatment with pegloticase at 1 of 4 dosage levels: 4 mg every 2 weeks, 8 mg every 2 weeks, 8 mg every 4 weeks, or 12 mg every 4 weeks. Plasma uricase activity, plasma urate, and antipegloticase antibodies were measured, pharmacokinetic parameters were assessed, and adverse events were recorded. RESULTS: The mean plasma urate level was reduced to

Efficacy and Safety of Febuxostat Extended and Immediate Release in Patients With Gout and Renal Impairment: A Phase III Placebo-Controlled Study.

OBJECTIVE: To assess the efficacy and safety of febuxostat extended release (XR) and immediate release (IR) in patients with gout and normal or impaired renal function. METHODS: This was a 3-month, phase III, multicenter, double-blind, placebo-controlled study. Patients (n = 1,790) with a history of gout and normal or impaired (mild-to-severe) renal function were randomized to receive placebo, febuxostat IR 40 or 80 mg, or febuxostat XR 40 or 80 mg once daily (1:1:1:1:1 ratio). End points included proportions of patients with a serum urate (UA) level of <5.0 mg/dl at month 3 (primary end point), a serum UA level of <6.0 mg/dl at month 3, and ≥1 gout flare requiring treatment over 3 months (secondary end points). RESULTS: Both febuxostat formulations led to significantly greater proportions of patients achieving a serum UA level of <5.0 mg/dl or <6.0 mg/dl at month 3 (P < 0.001 for all comparisons versus placebo). Equivalent doses of febuxostat XR and IR had similar treatment effects on serum UA level end points; however, a significantly greater proportion of patients achieved a serum UA level of <5.0 mg/dl with XR 40 mg versus IR 40 mg. Similar proportions of patients experienced ≥1 gout flare across treatment groups. Rates of treatment-emergent adverse events were low and evenly distributed between treatment arms. A preplanned subgroup analysis demonstrated that febuxostat formulations were well tolerated and generally effective on serum UA level end points (versus placebo) across all renal function subgroups. CONCLUSION: Both formulations of febuxostat (XR and IR) were well tolerated and effective in patients with gout and normal or impaired renal function, including patients with severe renal impairment.

Febuxostat compared with allopurinol in patients with hyperuricemia and gout.

BACKGROUND: Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase, is a potential alternative to allopurinol for patients with hyperuricemia and gout. METHODS: We randomly assigned 762 patients with gout and with serum urate concentrations of at least 8.0 mg per deciliter (480 micromol per liter) to receive either febuxostat (80 mg or 120 mg) or allopurinol (300 mg) once daily for 52 weeks; 760 received the study drug. Prophylaxis against gout flares with naproxen or colchicine was provided during weeks 1 through 8. The primary end point was a serum urate concentration of less than 6.0 mg per deciliter (360 micromol per liter) at the last three monthly measurements. The secondary end points included reduction in the incidence of gout flares and in tophus area. RESULTS: The primary end point was reached in 53 percent of patients receiving 80 mg of febuxostat, 62 percent of those receiving 120 mg of febuxostat, and 21 percent of those receiving allopurinol (P<0.001 for the comparison of each febuxostat group with the allopurinol group). Although the incidence of gout flares diminished with continued treatment, the overall incidence during weeks 9 through 52 was similar in all groups: 64 percent of patients receiving 80 mg of febuxostat, 70 percent of those receiving 120 mg of febuxostat, and 64 percent of those receiving allopurinol (P=0.99 for 80 mg of febuxostat vs. allopurinol; P=0.23 for 120 mg of febuxostat vs. allopurinol). The median reduction in tophus area was 83 percent in patients receiving 80 mg of febuxostat and 66 percent in those receiving 120 mg of febuxostat, as compared with 50 percent in those receiving allopurinol (P=0.08 for 80 mg of febuxostat vs. allopurinol; P=0.16 for 120 mg of febuxostat vs. allopurinol). More patients in the high-dose febuxostat group than in the allopurinol group (P=0.003) or the low-dose febuxostat group discontinued the study. Four of the 507 patients in the two febuxostat groups (0.8 percent) and none of the 253 patients in the allopurinol group died; all deaths were from causes that the investigators (while still blinded to treatment) judged to be unrelated to the study drugs (P=0.31 for the comparison between the combined febuxostat groups and the allopurinol group). CONCLUSIONS: Febuxostat, at a daily dose of 80 mg or 120 mg, was more effective than allopurinol at the commonly used fixed daily dose of 300 mg in lowering serum urate. Similar reductions in gout flares and tophus area occurred in all treatment groups.

Efficacy and safety of febuxostat extended release and immediate release in patients with gout and moderate renal impairment: phase II placebo-controlled study.

BACKGROUND: Febuxostat immediate release (IR), a xanthine oxidase inhibitor, is indicated for the management of hyperuricemia in patients with gout by lowering urate levels. An extended release (XR) formulation of febuxostat was developed to provide equal or superior efficacy on urate lowering compared with the IR formulation and potentially lower the risk of treatment-initiated gout flares due to an altered pattern of drug exposure. The present study evaluated the efficacy and safety of febuxostat XR and IR formulations in patients with gout and moderate renal impairment (estimated glomerular filtrate rate ≥ 30 and < 60 ml/min). METHODS: This was an exploratory, 3-month, phase II, multicenter, placebo-controlled, double-blind proof-of-concept study. Patients (n = 189) were randomized 1:1:1:1:1 to receive placebo or febuxostat IR 40 mg, XR 40 mg, IR 80 mg, or XR 80 mg once daily. Endpoints included: proportion of patients with serum uric acid (sUA) < 5.0 mg/dl at month 3 (primary endpoint), proportion of patients with sUA < 6.0 mg/dl at month 3, and proportion of patients with ≥ 1 gout flare requiring treatment over 3 months. RESULTS: At month 3, all febuxostat treatment groups were associated with greater proportions of patients achieving sUA < 5.0 mg/dl (p < 0.05 vs placebo). A greater proportion of patients receiving XR 40 mg achieved sUA < 5.0 mg/dl versus those receiving IR 40 mg (p = 0.034); proportions were similar in the IR 80 mg and XR 80 mg groups. Higher proportions of febuxostat-treated patients achieved sUA < 6.0 mg/dl at month 3 (p < 0.05 vs placebo) and experienced ≥ 1 gout flare (significant for all comparisons, except XR 40 mg). Incidences of treatment-related adverse events were low across all treatment groups; the majority were mild or moderate with no apparent trends correlating with IR or XR doses. The most common treatment-emergent adverse event was hypertension. One death (unrelated to the study drug) was reported. CONCLUSIONS: These exploratory data demonstrate that febuxostat (XR and IR) formulations were effective and well tolerated in patients with gout and moderate renal impairment. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02128490 Registered on 29 April 2014.

Real-time pulmonary graphic monitoring.

Real-time pulmonary graphics allow breath-to-breath assessment of pulmonary mechanics and patient-ventilator interaction. It allows the clinician to customize ventilator settings based on pathophysiology and patient response, and may enable detection of complications before they become clinically apparent. Graphics also provide objective information about the efficacy of pharmacologic agents and changes in patient status over time.