Histone locus bodies: a paradigm for how nuclear biomolecular condensates control cell cycle regulated gene expression

Histone locus bodies (HLBs) are biomolecular condensates that assemble at replication-dependent (RD) histone genes in animal cells. These genes produce unique mRNAs that are not polyadenylated and instead end in a conserved 3' stem loop critical for coordinated production of histone proteins during S phase of the cell cycle. Several evolutionarily conserved factors necessary for synthesis of RD histone mRNAs concentrate only in the HLB. Moreover, because HLBs are present throughout the cell cycle even though RD histone genes are only expressed during S phase, changes in HLB composition during cell cycle progression drive much of the cell cycle regulation of RD histone gene expression. Thus, HLBs provide a powerful opportunity to determine the cause-and-effect relationships between nuclear body formation and cell cycle regulated gene expression. In this review, we focus on progress during the last five years that has advanced our understanding of HLB biology.

Coordinating transcription and replication to mitigate their conflicts in early Drosophila embryos

Collisions between transcribing RNA polymerases and DNA replication forks are disruptive. The threat of collisions is particularly acute during the rapid early embryonic cell cycles of Drosophila when S phase occupies the entirety of interphase. We hypothesize that collision-avoidance mechanisms safeguard this early transcription. Real-time imaging of endogenously tagged RNA polymerase II (RNAPII) and a reporter for nascent transcripts in unperturbed embryos shows clustering of RNAPII at around 2 min after mitotic exit, followed by progressive dispersal as associated nascent transcripts accumulate later in interphase. Abrupt inhibition of various steps in DNA replication, including origin licensing, origin firing, and polymerization, suppresses post-mitotic RNAPII clustering and transcription in nuclear cycles. We propose that replication dependency defers the onset of transcription so that RNAPII transcribes behind advancing replication forks. The resulting orderly progression can explain how early embryos circumvent transcription-replication conflicts to express essential developmental genes.

Superresolution light microscopy of the Drosophila histone locus body reveals a core-shell organization associated with expression of replication-dependent histone genes

The histone locus body (HLB) is an evolutionarily conserved nuclear body that regulates the transcription and processing of replication-dependent (RD) histone mRNAs, which are the only eukaryotic mRNAs lacking a poly-A tail. Many nuclear bodies contain distinct domains, but how internal organization is related to nuclear body function is not fully understood. Here, we demonstrate using structured illumination microscopy that Drosophila HLBs have a “core–shell” organization in which the internal core contains transcriptionally active RD histone genes. The N-terminus of Mxc, which contains a domain required for Mxc oligomerization, HLB assembly, and RD histone gene expression, is enriched in the HLB core. In contrast, the C-terminus of Mxc is enriched in the HLB outer shell as is FLASH, a component of the active U7 snRNP that cotranscriptionally cleaves RD histone pre-mRNA. Consistent with these results, we show biochemically that FLASH binds directly to the Mxc C-terminal region. In the rapid S-M nuclear cycles of syncytial blastoderm Drosophila embryos, the HLB disassembles at mitosis and reassembles the core–shell arrangement as histone gene transcription is activated immediately after mitosis. Thus, the core–shell organization is coupled to zygotic histone gene transcription, revealing a link between HLB internal organization and RD histone gene expression.

CDK-Regulated Phase Separation Seeded by Histone Genes Ensures Precise Growth and Function of Histone Locus Bodies

Many membraneless organelles form through liquid-liquid phase separation, but how their size is controlled and whether size is linked to function remain poorly understood. The histone locus body (HLB) is an evolutionarily conserved nuclear body that regulates the transcription and processing of histone mRNAs. Here, we show that Drosophila HLBs form through phase separation. During embryogenesis, the size of HLBs is controlled in a precise and dynamic manner that is dependent on the cell cycle and zygotic histone gene activation. Control of HLB growth is achieved by a mechanism integrating nascent mRNAs at the histone locus, which facilitates phase separation, and the nuclear concentration of the scaffold protein multi-sex combs (Mxc), which is controlled by the activity of cyclin-dependent kinases. Reduced Cdk2 activity results in smaller HLBs and the appearance of nascent, misprocessed histone mRNAs. Thus, our experiments identify a mechanism linking nuclear body growth and size with gene expression.

A Comparison of Loratadine, a New Nonsedating Antihistamine, with Clemastine and Placebo in Patients with Fall Seasonal Allergic Rhinitis

Loratadine is a new nonsedating long-acting H1-antagonist which has been shown to be effective at various doses in controlling symptoms of spring seasonal allergic rhinitis. In this multicenter, double-blind, parallel study, 313 adolescent and adult patients with moderate to severe, skin-test positive, fall seasonal rhinitis were randomized to receive either loratadine, 10 mg, in the morning and placebo in the evening, clemastine 1 mg. b.i.d., or placebo b.i.d. for 2 weeks. Patients maintained daily diaries of nasal and ocular symptoms and of adverse effects. They were evaluated before and 7 and 14 days after starting treatment. The mean symptom scores on days 7 and 14 showed greater improvement with both loratadine and clemastine treatments than with placebo. The incidence of somnolence in the loratadine group by comparison with the placebo group was not statistically different, whereas clemastine caused significantly more drowsiness than did placebo. We conclude that loratadine, 10 mg, once a day is as effective as clemastine b.i.d. in decreasing the symptoms of fall seasonal rhinitis and the incidence of somnolence with loratadine is not statistically different from that with placebo.

CRMP-1 enhances EVL-mediated actin elongation to build lamellipodia and the actin cortex

CRMP proteins regulate the cytoskeleton, but the underlying mechanisms are poorly understood. Yu-Kemp et al. show that CRMP-1 helps Ena/VASP proteins elongate actin filaments to assemble actin networks that are necessary for the integrity of epithelial sheets.

Cells can control actin polymerization by nucleating new filaments or elongating existing ones. We recently identified CRMP-1 as a factor that stimulates the formation of Listeria monocytogenes actin comet tails, thereby implicating it in actin assembly. We now show that CRMP-1 is a major contributor to actin assembly in epithelial cells, where it works with the Ena/VASP family member EVL to assemble the actin cytoskeleton in the apical cortex and in protruding lamellipodia. CRMP-1 and EVL bind to one another and together accelerate actin filament barbed-end elongation. CRMP-1 also stimulates actin assembly in the presence of VASP and Mena in vitro, but CRMP-1–dependent actin assembly in MDCK cells is EVL specific. Our results identify CRMP-1 as a novel regulator of actin filament elongation and reveal a surprisingly important role for CRMP-1, EVL, and actin polymerization in maintaining the structural integrity of epithelial sheets.

Distinct relationships of intramuscular and subcutaneous fat with cortical bone: findings from a cross-sectional study of young adult males and females

CONTEXT

Intracellular fat within muscle and visceral tissue has been suggested to adversely influence bone development.

OBJECTIVE

The aim of the study was to evaluate associations between im fat, as reflected by muscle density as measured by peripheral quantitative computed tomography, and cortical bone parameters in young adults.

DESIGN/SETTING/PARTICIPANTS

We conducted a cross-sectional analysis of 1703 males and 2243 females aged 17.8 years from the Avon Longitudinal Study of Parents and Children.

OUTCOME MEASURES

We measured cortical bone parameters from midtibial peripheral quantitative computed tomography scans.

RESULTS

Muscle density (inversely related to im fat) was inversely associated with periosteal circumference (PC) (beta = -0.07 [95% confidence interval (CI), -0.1, -0.04]), cortical bone mineral density (BMDC) (beta = -0.21 [95% CI, -0.26, -0.17]), and cortical thickness (CT) (beta = -0.37 [95% CI, -0.42, -0.33]) (males and females combined, adjusted for age, height, gender, and muscle cross-sectional area). In contrast, sc fat area was positively associated with PC (beta = 0.10 [95% CI, 0.07, 0.12]), but no association was seen with BMDC or CT. To examine the role of candidate intermediary metabolic pathways, analyses were repeated after adjustment for insulin, C-reactive protein, and β-C-telopeptides of type I collagen. Whereas similar associations were observed after adjustment for insulin and C-reactive protein, the association between muscle density and BMDC was partially attenuated by adjustment for β-C-telopeptides of type I collagen (beta = -0.14 [95% CI, -0.20, -0.08]).

CONCLUSION

Although im and sc fat were both positively associated with cortical bone mass, the nature of these relationships differed in that im fat was predominantly associated with CT and BMDC, whereas sc fat was mainly associated with PC. These relationships were largely independent of candidate metabolic pathways, such as altered bone resorption, insulin resistance, or inflammation.

Onset and duration of attenuation of exercise-induced bronchoconstriction in children by single-dose of montelukast

Single-dose montelukast attenuates exercise-induced bronchoconstriction (EIB) in adults within 2 hours postdose and lasting through 24 hours. This study evaluated the onset and duration of EIB attenuation in children after a single dose of montelukast. A randomized, double-blind, placebo-controlled, two-period crossover study was performed. Patients (n = 66) aged 4-14 years, with preexercise forced expiratory volume in 1 second of (FEV(1)) ≥70% predicted and maximum percentage fall in FEV(1) of ≥20% at two screening exercise challenges were eligible. Patients were to receive single-dose montelukast (4 or 5 mg) or placebo before performing standardized exercise challenges at 2 and 24 hours postdose. A 3- to-7-day washout separated the two crossover periods. The primary end point was maximum percentage fall in FEV(1) after exercise challenge 2 hours postdose. Secondary end points included maximum percentage fall in FEV(1) after the 24-hour postdose challenge; each of the following at 2 and 24 hours postdose-maximum percentage fall in FEV(1) categorized as <10%, 10-20%, or >20%; area under the curve (AUC) during 60 minutes postchallenge; time to recovery of FEV(1) to within 5% of preexercise baseline; and need for rescue medication. The mean maximum percentage fall in FEV(1) after the 2-hour postdose exercise challenge was significantly attenuated after single-dose montelukast compared with placebo (15.35% versus 20.00%; p = 0.020). Montelukast was also significantly more effective than placebo for maximum percentage fall after the 24-hour challenge (12.92% versus 17.25%; p = 0.005), the categorized maximum percent fall in FEV(1) at 2 hours (p = 0.034), and AUC at 2 hours (p = 0.022) and 24 hours (p = 0.013). Single-dose montelukast provided rapid and sustained EIB attenuation in children. Clinicaltrials.gov identifier: NCT00534976.

Exercise-induced bronchoconstriction: The effects of montelukast, a leukotriene receptor antagonist

Exercise-induced bronchoconstriction (EIB) is very common in both patients with asthma and those who are otherwise thought to be normal. The intensity of exercise as well as the type of exercise is important in producing symptoms. This may make some types of exercise such as swimming more suitable and extended running more difficult for patients with this condition. A better understanding of EIB will allow the physician to direct the patient towards a type of exercise and medications that can result in a more active lifestyle without the same concern for resulting symptoms. This is especially important for schoolchildren who are usually enrolled in physical education classes and elite athletes who may desire to participate in competitive sports. Fortunately several medications (short- and long-acting beta(2)-agonists, cromolyn, nedocromil, inhaled corticosteroids, and more recently leukotriene modifiers) have been shown to be effective in preventing or attenuating the effects of exercise in many patients. In addition, inhaled beta(2)-agonists have been shown to quickly reverse the airway obstruction that develops in patients and continue to be the reliever medications of choice. Inhaled corticosteroids are increasingly being recommended as regular therapy now that the role of inflammation and airway injury has been identified in EIB. With the discovery that there is a release of mediators such as histamine and leukotrienes from cells in the airway following exercise with resulting airway obstruction in susceptible individuals, interest has turned to attenuating their effects with mediator antagonists especially those that block the effects of leukotrienes. Studies with an oral leukotriene antagonist, montelukast, have shown beneficial effects in adults and children aged as young as 6 years with EIB. These effects can be demonstrated as soon as two hours and as long as 24 hours after administration without a demonstrated loss of a protective effect after months of treatment. The studies leading up to and resulting in an approval of montelukast for EIB for patients aged 15 years and older are reviewed in this paper.

Advances in the management of pediatric asthma: a review of recent FDA drug approvals and label updates

Children have the highest prevalence of asthma of any age group. In the United States during 2001, there were 12.6 million physician and hospital outpatient visits for asthma treatment, of which almost 5 million involved children 18 years and younger. Therapeutic advances in pediatric asthma could improve patient outcomes and potentially reduce the burden on health care systems. Efforts to obtain efficacy and safety data in pediatric populations and develop pediatric formulations of asthma treatments have been encouraged by the FDA and clinicians. This article reviews the newest additions to asthma therapies approved for use in children, including an inhaled corticosteroid, some long-acting beta2-agonists, some leukotriene-receptor blockers, and a single-isomer, short-acting beta2-agonist.

Potential effects of fluticasone propionate on bone mineral density in patients with asthma: a 2-year randomized, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate the effects of treatment with fluticasone propionate vs placebo on bone, hypothalamic-pituitary-adrenal (HPA) axis function, and the eyes in patients with asthma.

PATIENTS AND METHODS

This randomized, double-blind, placebo-controlled study of 160 patients with asthma who had minimal previous exposure to corticosteroids was conducted from July 1994 through June 1997. Patients received fluticasone at 88 microg twice daily, fluticasone at 440 microg twice daily, or placebo twice daily for 2 years. Bone mineral density (BMD) was evaluated every 6 months by lumbar spine, proximal femur, and total body scans. Measurements of HPA axis function and ophthalmic evaluations were conducted at similar intervals.

RESULTS

Among the 3 groups, no significant differences were observed in BMD at week 104 (at any anatomical site). Mean percent change from baseline in the lumbar spine was less than 1% for all 3 groups. At all time points, HPA axis function was similar in the 88-microg fluticasone group compared with the placebo group. For mean change from baseline in corticotropin-stimulated peak cortisol (P = .003 and P = .02 at weeks 24 and 52, respectively) and area under the stimulated plasma cortisol vs time curve (P = .002 and P = .02 at weeks 24 and 52, respectively), statistically significant reductions from baseline were observed in the 440-microg fluticasone group compared with the placebo group. These reductions of 10% to 13% from baseline were not accompanied by other signs of systemic effect and did not persist with continued treatment (at weeks 76 and 104). No important ocular changes were observed.

CONCLUSION

Long-term treatment with 88 microg of fluticasone twice daily was comparable to placebo in all skeletal, ophthalmic, and HPA axis function assessments. Treatment with fluticasone at 440 microg twice daily resulted in no significant effects on BMD and a statistically significant but not clinically important temporary reduction in cortisol production.

Recent advances in the management of asthma using leukotriene modifiers

Asthma is a chronic inflammatory disease of the airways that affects approximately 100 million people worldwide. In order to reduce symptoms, improve pulmonary function, and decrease morbidity, current treatment guidelines emphasize the importance of controlling the underlying inflammation in patients with asthma. Leukotrienes are leukocyte-generated lipid mediators that promote airway inflammation. Recognition of the importance of leukotrienes in the pathogenesis of asthma has led to the development of leukotriene modifiers, the first new class of drugs for the treatment of asthma to become available in 25 years. Controlled clinical trials with the four currently used leukotriene modifiers (montelukast, zafirlukast, and zileuton in the US and pranlukast in Japan) have established their efficacy in improving pulmonary function, reducing symptoms, decreasing night-time awakenings, and decreasing the need for rescue medications. They exert anti-inflammatory effects that attenuate cellular infiltration and bronchial hyperresponsiveness and complement the anti-inflammatory properties of inhaled corticosteroids. In patients with moderate and severe asthma, they permit tapering of the corticosteroid dose. In patients with exercise-induced asthma, leukotriene modifiers limit the decline in and quicken the recovery of pulmonary functions without the tolerance issues seen with chronic long-acting beta(2)-adrenoceptor agonist use. In patients with aspirin (acetylsalicylic acid)-induced asthma, they improve pulmonary function and shift the dose response curve to the right, reducing the patient's response to aspirin. In patients with seasonal allergic rhinitis, with or without concomitant asthma, they improve nasal, eye, and throat symptoms as well as quality of life. Leukotriene modifiers are generally safe and well tolerated with adverse effect profiles similar to that of placebo. The one safety issue raised with leukotriene modifiers, Churg-Strauss Syndrome, appears to be the unmasking of an already present syndrome that is manifested when the leukotriene modifiers permit corticosteroid doses to be reduced. Although current treatment guidelines recommend their use in patients with mild persistent asthma, these guidelines were developed just as leukotriene modifiers were coming to the market, before much of the clinical efficacy data were published. Because asthma is a heterogeneous disease, the different asthma phenotypes respond differently to therapies; consequently asthma therapy needs to be individualized. Leukotriene modifiers increase the therapeutic options for patients with asthma and, based on recent data, it is expected that future guidelines will describe expanded uses for these agents in clinical circumstances where these drugs are effective.

Helical structures in proteins

We examine a minimal model for helix-forming polymers. The monomer-monomer potential energy is based on the anisotropic potentials seen in proteins and is used in conjunction with a wormlike backbone. We show that the coil-helix transition involves four states. As the temperature is lowered, the first observed state is a coil state, the second a collapsed globular, the third a highly flexible helical state, and the fourth a crystalline helical state. We discuss in detail what effect the potential energy form has on these various states by systematically varying the potential from strongly anisotropic to isotropic. The data demonstrate that the foldability of a helix is strongly related to anisotropic nature of the potential. In the isotropic case, we show that the transition following a globular collapse is not first order as postulated for these systems. In the strongly anisotropic case the globular-helix transition is consistent with cooperative first-order-like behavior.

Efficacy of antileukotriene agents in asthma management

OBJECTIVE

This article reviews information on the role of three antileukotrienes (anti-LTs), montelukast, zafirlukast, and zileuton, in the management of asthma. After reading this article, readers should have an understanding of the efficacy of anti-LTs in specific patient populations.

DATA SOURCES

Relevant and appropriately controlled clinical studies on the efficacy of anti-LTs were used. Only literature in the English language was reviewed.

STUDY SELECTION

Material was taken from peer-reviewed journals and published abstracts.

RESULTS

The efficacy of anti-LTs has been established in numerous randomized, controlled, multicenter trials involving patients with mild-to-moderate disease. These agents reduce asthma symptoms, beta2-agonist use, and asthma exacerbations, in addition to improving pulmonary function. The anti-LTs are also effective when added to low-dose or high-dose corticosteroid regimens in symptomatic asthma patients. They have proven efficacy in patients with aspirin-sensitive asthma, and they appear able to reduce nasal congestion in asthma patients with concomitant upper airway symptoms. Some anti-LTs have been shown to be effective in pediatric asthma patients.

CONCLUSIONS

In reviewing available clinical results as well as real-world experience in managing asthma patients, the Antileukotriene Working Group concludes that anti-LTs may be used in patients with mild persistent asthma as well as in combination with other asthma medications at all levels of disease severity for long-term maintenance of asthma control.

Management of asthma in children

The prevalence of asthma in children has increased 160 percent since 1980, and the disease currently affects nearly 5 million children in the United States. The National Asthma Education and Prevention Program provides guidelines for improved asthma care. The goals of this program are to limit the frequency, severity and costliness of asthma exacerbations through extensive education of physicians, children and caregivers. The four components of asthma management include regular assessment and monitoring, control of factors that contribute to or aggravate symptoms, pharmacologic therapy and education of children and their caregivers. The guidelines recommend a stepwise approach to pharmacologic treatment, starting with aggressive therapy to achieve control and followed by a "step down" to the minimal therapy that will maintain control. Quick relief of symptoms can be achieved preferentially by the use of short-acting beta2 agonists. Medications for long-term control should be considered for use in children with persistent symptoms. Inhaled corticosteroids are the most potent long-term anti-inflammatory medications. Other options include long-acting beta2 agonists, cromolyn sodium and nedocromil, antileukotriene agents and theophylline. All have advantages and disadvantages in individual situations.

Mometasone furoate administered once daily is as effective as twice-daily administration for treatment of mild-to-moderate persistent asthma

BACKGROUND

Despite current recommendations, many patients with persistent asthma are still treated with bronchodilators alone.

OBJECTIVE

The safety and efficacy of two once daily dosing regimens (200 microg and 400 microg) of mometasone furoate (MF) administered in the morning by using a dry-powder inhaler (DPI) were compared with those of a twice daily dosing regimen (200 microg administered twice daily) in patients with mild-to-moderate persistent asthma previously taking only inhaled beta(2)-adrenergic agonists.

METHODS

All patients (306 patients; age range, 12-70 years) were given a diagnosis of asthma for at least 6 months before enrollment in this 12-week, placebo-controlled, double-blind, randomized study. The primary efficacy variable was change in FEV(1) from baseline to endpoint (last evaluable visit).

RESULTS

At endpoint, FEV(1) was significantly improved (P < or =.02) after MF-DPI 400 microg once daily morning treatment and MF-DPI 200 microg twice daily treatment (16.0% and 16.1%, respectively) compared with placebo (5.5%). The improvement seen with MF-DPI 200 microg once daily morning treatment (10.4%) was not significantly different from that with placebo. Secondary efficacy variables also showed significant improvement for the MF-DPI 400 microg once daily morning treatment group and the MF-DPI 200 microg twice daily treatment group compared with the placebo group. All doses of MF administered by means of a DPI were well tolerated.

CONCLUSION

This is the first study to demonstrate that a total daily dose of 400 microg of MF administered by means of a DPI is an effective treatment for patients with mild-to-moderate persistent asthma previously taking only inhaled beta(2)-adrenergic agonists. This treatment was equally effective when administered either as a once daily or twice daily regimen.

Role of leukotriene receptor antagonists in pediatric asthma

During the past decade, the inflammatory mechanisms that result in the clinical syndrome we call asthma have been emphasized in research, publications, and the various asthma management guidelines. This information clearly emphasizes the treatment of asthma with maintenance controller therapies early after the onset of symptoms in all but the very mildest of patients. Until the advent of the leukotriene receptor antagonists, nearly all of these maintenance therapies needed to be administered by inhalation through a variety of devices and spacers. Inhalation of medication was necessary to either increase the amount of drug reaching the airways or to increase the therapeutic index of drugs such as corticosteroids. Even under the best circumstances, this route of administration is difficult and expensive for many parents whose children have asthma. Now that oral controller therapies (leukotriene receptor antagonists) are available for children, their role in clinical practice needs to be examined. The latest asthma management guidelines classify asthma into four groups of severity, and base treatment recommendations on the intensity of symptoms, need for rescue medications, and pulmonary function as measured by peak expiratory flow and forced expiratory volume in 1 sec (FEV(1)). The categories of mild intermittent, mild persistent, moderate persistent, and severe asthma in children will be addressed in this presentation by reviewing the available data on the use of the leukotriene receptor antagonist montelukast in children. Mild intermittent asthma can be typified by exercise-induced asthma, a common pediatric condition. In this often troublesome condition, montelukast demonstrated effectiveness at the end of a once a day dose by blocking the effects of this naturally occurring challenge. Drug regulatory approval of a new drug also includes patients with more regular symptoms who are usually classified as having persistent or moderate asthma. In these montelukast pediatric studies, approximately 40% of patients were already taking inhaled corticosteroids. Patients had improvements in FEV(1), symptoms, and rescue medication use, clearly showing an effect with once a day dosing. Pediatric data in severe asthma patients are more limited, but in such patients a therapeutic trial of montelukast would seem preferable to using systemic corticosteroids or increasing inhaled steroids to a level where adverse effects have an increasing potential of occurring. Montelukast has been available in the United States since March 1998 and has received excellent acceptance by physicians, parents, and patients. The 5-mg chewable tablet administered once a day in the evening in children aged 6-14 years apparently fills a previously unmet need in the treatment of pediatric asthma.

Guidelines update: where do the new therapies fit in the management of asthma? NHLBI and WHO Global Initiative for Asthma

The new leukotriene (LT) modifiers have been shown to be effective, safe and convenient 'controller' medications in patients with asthma. However, their use in asthma is recommended only in the most recent US guidelines, and then only as alternative long term controllers in patients with mild persistent asthma. In fact, as has now been shown in a number of studies, LT modifiers are effective in a variety of other asthma settings, and it is expected that expanded roles for these agents will be described in future asthma guidelines. Until then, clinicians aware of the advantages of individualising asthma therapy might consider LT modifiers for the diverse range of patients with asthma who are likely to benefit from the use of these agents.

Leukotriene receptor antagonists for the treatment of asthma

Leukotriene receptor antagonists (LTRAs) are novel medications that provide symptom control in patients with persistent asthma. Current guidelines recommend the use of LTRAs as a treatment option for patients with mild-persistent asthma of at least 12 years of age. As illustrated by the results of controlled, multicenter clinical trials with zafirlukast and montelukast, as well as studies with pranlukast in Japan, LTRAs reduce daytime and night time asthma symptoms, improve pulmonary function, lower beta-adrenergic agonist use, and reduce asthma morbidity in patients with mild-intermittent to moderate-persistent asthma. Moreover, several recent clinical studies demonstrate that these agents are effective in preventing exercise-induced bronchoconstriction in children, and in improving disease control in symptomatic patients taking inhaled steroids. Based on clinical results to date, LTRAs appear to be safe and well tolerated in patients with mildto- moderate asthma. These agents represent an important addition to the drug armamentarium against asthma.

Effect of age on response to zafirlukast in patients with asthma in the Accolate Clinical Experience and Pharmacoepidemiology Trial (ACCEPT)

BACKGROUND

The Accolate Clinical Experience and Pharmacoepidemiology Trial (ACCEPT), evaluated zafirlukast in a wide spectrum of patients from a variety of clinical practices.

OBJECTIVE

To determine the effect of age on the response to zafirlukast 20 mg twice daily in 3759 patients with mild, moderate, or severe asthma.

METHODS

Patients received open-label administration of zafirlukast 20 mg twice daily (bid) for 4 weeks. Pulmonary function was measured twice daily, and overall asthma symptom scores, number of nighttime awakenings, severity of morning asthma symptoms, and beta2-agonist use were recorded daily. Trial results were analyzed to compare the efficacy of zafirlukast in 263 adolescent (12 to 17 years old), 2602 adult (18 to 65 years old), and 321 elderly (66 years old and older) patients (the evaluable population).

RESULTS

After 4 weeks of zafirlukast therapy, improvements in pulmonary function decreased with age and were significant for all measures in adolescents and adults and for morning peak expiratory flow in elderly patients. Improvements in symptom response were statistically significant across age groups. Reduction in beta2-agonist rescue was similar in adolescents and adults but significantly less in elderly patients.

CONCLUSIONS

Zafirlukast is an effective treatment for asthma in all patients, regardless of age. In elderly patients, improvement in asthma symptoms rather than pulmonary function may represent a primary marker for efficacy with zafirlukast.

Oral montelukast compared with inhaled salmeterol to prevent exercise-induced bronchoconstriction. A randomized, double-blind trial. Exercise Study Group

BACKGROUND

Montelukast, an oral, once-daily leukotriene receptor antagonist, provides protection against exercise-induced bronchoconstriction.

OBJECTIVE

To evaluate the effect of 8 weeks of therapy with salmeterol aerosol or montelukast on exercise-induced bronchoconstriction in adults with asthma.

DESIGN

8-week multicenter, randomized, double-blind study.

SETTING

17 asthma treatment centers in the United States.

PATIENTS

191 adults with asthma who had documented exercise-induced bronchoconstriction.

INTERVENTION

Qualified patients were randomly assigned to double-blind treatment with montelukast (10 mg once in the evening) or salmeterol (50 microg [2 puffs] twice daily).

MEASUREMENTS

Changes in pre-exercise and postexercise challenge values; percentage inhibition in the maximal percentage decrease in FEV1; the area above the FEV1-time curve; and time to recovery of FEV1 at days 1 to 3, week 4, and week 8 of treatment.

RESULTS

By day 3, similar and statistically significant reductions in maximal percentage decrease in FEV1 were seen with both therapies. Sustained improvement occurred in the montelukast group at weeks 4 and 8; at these time points, the bronchoprotective effect of salmeterol decreased significantly. At week 8, the percentage inhibition in the maximal percentage decrease in FEV1 was 57.2% in the montelukast group and 33.0% in the salmeterol group (P = 0.002). By week 8, 67% of patients receiving montelukast and 46% of patients receiving salmeterol had a maximal percentage decrease in FEV1 of less than 20%.

CONCLUSIONS

The bronchoprotective effect of montelukast was maintained throughout 8 weeks of study. In contrast, significant loss of bronchoprotection at weeks 4 and 8 was seen with salmeterol. Long-term administration of montelukast provided consistent inhibition of exercise-induced bronchoconstriction at the end of the 8-week dosing interval without tolerance.

A 1-year study of salmeterol powder on pulmonary function and hyperresponsiveness to methacholine

BACKGROUND

Long-acting beta(2)-sympathomimetic agonists such as salmeterol have been proved safe and effective for the treatment of asthma. However, controversy still exists as to the appropriateness of scheduled long-term therapy with these agents.

OBJECTIVE

This study assessed the degree of bronchodilation provided by treatment with salmeterol for a period of 52 weeks and evaluated bronchial hyperresponsiveness to methacholine during and after the treatment period.

METHODS

Three hundred fifty-two patients with mild to moderate asthma were assessed by 12-hour serial spirometry and serial methacholine challenge tests.

RESULTS

The mean area under the FEV(1) curve above baseline over 12 hours after drug at day 1 was significantly greater with salmeterol powder compared with placebo (5.06 liter hours vs 0.77 L/h) and did not change significantly over 1 year. The mean increase in the log(2) of the provocative cumulative methacholine dose producing a 20% decrease in FEV(1) (PD(20)FEV(1)) during treatment was significantly higher in the salmeterol-treated patients than in the placebo group (1.02 doubling doses vs 0.43 doubling doses at week 4, 1.06 doubling doses vs 0.41 doubling doses at week 24). At week 52 the increase from baseline in log(2)PD(20)FEV(1) was not significantly different between salmeterol and placebo (1.08 vs 0.69 doubling doses). Seven days after treatment the log(2)PD(20)FEV(1) was -0.60 doubling doses lower than baseline for salmeterol compared with 0.10 doubling doses for placebo (P =.031). Long-term salmeterol use was not associated with a deleterious effect on asthma control during and after treatment.

CONCLUSION

This study demonstrates that the bronchodilator properties of salmeterol are sustained over 52 weeks and that bronchial hyperresponsiveness to methacholine is decreased to a modest degree during treatment. Clinically significant increases in hyperresponsiveness did not develop after discontinuation of salmeterol treatment.

Study designs and challenges in clinical studies conducted in infants and children with asthma

Because of the challenges associated with conducting clinical trials in pediatric patients, most drugs have not been adequately tested in this patient population. Insufficient testing frequently results in product labeling that fails to provide instructions for safe and effective use in pediatric patients. The most prevalent chronic disease in children is asthma; however, very few asthma medications have been evaluated in infants and young children. Budesonide inhalation suspension is an anti-inflammatory corticosteroid administered by nebulization that requires only passive inhalation and is therefore suitable for infants and young children who are unable to use currently available inhalation devices for the administration of asthma medications. The efficacy of budesonide inhalation suspension was evaluated in 3 US clinical trials. All 3 trials were randomized, controlled, double-blind, 12-week studies in children (6 months-8 years of age) with a primary diagnosis of chronic persistent asthma. Symptom assessments conducted in both the morning and evening were the primary efficacy variables. Although the children were young, secondary efficacy evaluations included spirometry and peak expiratory flow collected in both the morning and evening (in a subset of patients capable of performing these maneuvers). Patients who completed or were discontinued from the 12-week double-blind treatment phase were eligible to enter 52-week, open-label extension studies. The design of these 3 studies confirms the feasibility of the performance of placebo-controlled clinical trials of asthma medications in pediatric patients and allows for efficacy evaluations based on symptom assessments together with pulmonary function testing.

Once-daily budesonide inhalation suspension for the treatment of persistent asthma in infants and young children

BACKGROUND

Inhaled glucocorticosteroids (GCS) are the most effective long-term controller medications for the treatment of persistent asthma. Currently, however, available delivery devices limit their use in young children. A nebulized formulation of budesonide has been developed to address the needs of infants and young children.

OBJECTIVE

To evaluate the efficacy and safety of once-daily budesonide inhalation suspension in children 6 months to 8 years old with mild persistent asthma not on inhaled GCS.

METHODS

Three hundred fifty-nine children were randomized to receive once-daily budesonide inhalation suspension (0.25 mg, 0.50 mg, or 1.0 mg) or placebo via a Pari LC-Jet Plus nebulizer for 12 weeks. Efficacy assessments included nighttime/daytime asthma symptoms, pulmonary function (subset of patients), rescue medication use, and treatment discontinuations. Safety was based on adverse events and assessment of HPA-axis function.

RESULTS

Demographics, baseline characteristics, asthma symptoms, and pulmonary function were similar across treatment groups. Mean nighttime/daytime asthma symptom scores were 1.19 +/- 0.63 and 1.34 +/- 0.53, respectively. Mean duration of asthma was 36.3 months and mean FEV1 was 81.3% of predicted with 27.7% reversibility. Following 12 weeks of treatment, all budesonide inhalation suspension doses produced significant improvements in nighttime/daytime symptoms (P < or = .049) and significant decreases in rescue medication use (P < or = .038) compared with placebo. Significant improvements (P < or = .044) in FEV1 were observed in the 0.5- and 1.0-mg budesonide inhalation suspension groups. There were no differences between doses of budesonide inhalation suspension. Adverse events and basal and ACTH-stimulated cortisol levels were similar among all groups.

CONCLUSION

Once-daily administration of budesonide inhalation suspension was well tolerated and effective for the treatment of mild persistent asthma in infants and young children not adequately controlled with bronchodilators or non-GCS antiinflammatory treatments.

Semianalytical calculation of the Rouse dynamics of randomly branched polymers

We present a semianalytical approach to the determination of the dynamic properties of randomly branched polymers under the Rouse approximation. The principal procedure is based on examining an eigenvalue spectrum which represents the average dynamic behavior of various structures. The calculated spectra show that the eigenvalue distribution is random even within a single structure, which in turn produces a continuous spectrum of values for the entire class. The autocorrelation function for the square of the radius of gyration was calculated based on these spectra, which confirms that the dynamics are nonexponential as earlier reported. A universal stretched exponent is also found in this study.

Effect of long-term salmeterol therapy compared with as-needed albuterol use on airway hyperresponsiveness

STUDY OBJECTIVES

To determine the effect of long-term salmeterol aerosol therapy on airway hyperresponsiveness measured by methacholine challenge.

DESIGN

Randomized, double-blind, placebo-controlled, multicenter study.

SETTING

Thirty-one clinical centers in the United States.

PATIENTS

Four hundred eight asthmatic patients > or = 12 years of age with baseline FEV1 of > or = 70% of predicted values. Patients were not using inhaled corticosteroids.

INTERVENTIONS

Twice-daily salmeterol aerosol, 42 microg, or placebo via metered-dose inhaler for 24 weeks. Backup albuterol was available.

MEASUREMENTS AND RESULTS

Pulmonary function tests were performed before, during, and after treatment. Subjects recorded asthma-related symptoms, morning and evening peak expiratory flow (PEF) levels, and use of supplemental albuterol daily on diary cards. Methacholine challenges were performed 10 to 14 h postdose at weeks 4, 12, and 24, and 3 and 7 days posttreatment. Over 24 weeks of treatment, salmeterol provided significant (p < 0.001) protection against methacholine-induced bronchoconstriction of approximately one doubling dose of methacholine when compared to placebo with no evidence for a progressive decrease in protection. A rebound increase in airway hyperresponsiveness was not observed 3 and 7 days after cessation of salmeterol therapy. Salmeterol treatment resulted in sustained improvements of 0.21 to 0.26 L in morning premedication FEV1 and an improvement of 26.2 L/min in morning PEF when compared to placebo (p < 0.001). The use of salmeterol significantly reduced combined daytime asthma symptoms by 20% when compared to placebo (p = 0.005). A total of 34 and 48 exacerbations, respectively, were reported in the Salmeterol and placebo groups, and no evidence was present for a difference in the severity of asthma exacerbations between groups. Adverse event profiles were similar for the salmeterol and placebo groups.

CONCLUSIONS

Regular long-term use of salmeterol aerosol resulted in sustained improvements in pulmonary function and asthma symptom control over the 24-week treatment period. There was no increase in bronchial hyperresponsiveness or loss of bronchoprotection at 24 weeks from that seen following 4 weeks of therapy. There was no evidence of rebound airway hyperresponsiveness after cessation of salmeterol treatment. Regular treatment with the long-acting beta-agonist salmeterol does not lead to clinical instability or vulnerability to unpredictable asthma attacks.

Dose-ranging study of a new steroid for asthma: mometasone furoate dry powder inhaler

A new formulation of mometasone furoate (MF) for administration by dry powder inhaler (DPI) was evaluated for the treatment of asthma. A 12-week, double-blind, placebo-controlled dose-ranging study compared the efficacy and safety of three doses of MF DPI (100, 200 and 400 mcg b.i.d) with beclomethasone dipropionate (BDP) 168 mcg b.i.d. administered by metered dose inhaler in 365 adult or adolescent patients being treated with inhaled glucocorticoids. The mean change from baseline to endpoint (last treatment visit) for forced expiratory volume in 1 sec (FEV1) was the primary efficacy variable. Secondary efficacy variables included other objective measures of pulmonary function [forced vital capacity (FVC), forced expiratory flow 25-75% (FEV25-75%.) and peak expiratory flow rate (PEFR)] as well as subjective measures of therapeutic response (patients' daily evaluation of asthma symptoms and physicians' evaluation). At endpoint, all four active treatments were significantly more effective than placebo (P < 0.01) in improving FEV1 (MF DPI 5 to 7%, BDP 3%, placebo -6.6%) and all other measures of pulmonary function (FVC: MF DPI 4 to 5%, BDP 2%, placebo -4.7%; FEF25-75%: MF DPI 6 to 18%, BDP 7.5%, placebo -9.5%; PEFR (AM): MF DPI 5 to 10%, BDP 5.7%, placebo -7%). A consistent trend was observed for better improvement in patients treated with MF DPI 200 mcg b.i.d. than with MF DPI 100 mcg b.i.d., with no apparent additional benefit of MF DPI 400 mcg b.i.d. Results for the MF DPI 100 mcg b.i.d. and BDP 168 mcg b.i.d. treatment groups were similar. Patients' and physicians' subjective evaluations of symptoms found similar improvement in the MF DPI 200 and 400 mcg b.i.d. treatment groups, which were slightly better than that in the MF DPI 100 mcg b.i.d. group. Symptoms tended to worsen in the placebo group. MF DPI was well tolerated at all dose levels and the most frequently reported treatment-related adverse effects were headache, pharyngitis and oral candidiasis. No evidence of HPA-axis suppression was detected in any treatment group. In summary, all doses of MF DPI were well tolerated and significantly improved lung function and MF DPI 400 mcg (200 mcg b.i.d.) was the optimal dose in this study of patients with moderate persistent asthma.

Administration of budesonide once daily by means of turbuhaler to subjects with stable asthma

BACKGROUND

Optimal management of chronic, mild-to-moderate asthma with inhaled steroids may include use of the lowest possible doses, as recommended in guidelines, and a reduction in the frequency of daily administration for greater convenience. Lower doses and once daily treatment with inhaled steroids must be rigorously evaluated in controlled clinical trials.

OBJECTIVES

The objective of this study was to assess the efficacy and safety of once daily treatment with budesonide in subjects with stable asthma.

METHODS

Once daily budesonide was assessed in 309 adult subjects, including those who were and were not using an inhaled steroid at baseline. The subjects were stratified by inhaled steroid use and randomly assigned to one of 3 treatments: 200 microgram budesonide, 400 microgram budesonide, or placebo administered by means of Turbuhaler once daily in the morning for 6 weeks. Beyond this point, treatment was continued unchanged for another 12 weeks (maintenance) in those receiving 200 microgram budesonide once daily and placebo. In those who received 400 microgram budesonide once daily, the dose was reduced to 200 microgram once daily at week 6 and held constant for the remaining 12 weeks (400/200 microgram group). Primary efficacy endpoints were mean change from baseline in FEV1 and morning peak expiratory flow.

RESULTS

Once daily budesonide was well tolerated and resulted in significant improvements in all efficacy endpoints, even though baselines were well stabilized. Baseline lung function was elevated with little room for improvement; however, mean increases in FEV1 during the maintenance period were 0.10 L and 0.11 L in the 200 microgram and 400/200 microgram groups, respectively, versus a decrease of -0.09 L in the placebo arm (P <.001). Results for peak expiratory flow were similar. Significant improvements in secondary endpoints, including symptoms, beta-agonist use, and quality of life, also developed with budesonide 200 and 400 microgram once daily.

CONCLUSION

Inhaled budesonide, in doses as low as 200 microgram, may be an appropriate introductory or maintenance dose in subjects with stable, mild-to-moderate asthma.

Zafirlukast in clinical practice: results of the Accolate Clinical Experience and Pharmacoepidemiology Trial (ACCEPT) in patients with asthma

BACKGROUND

Zafirlukast is an oral leukotriene receptor antagonist used in the treatment of patients with mild to moderate asthma. To investigate its effects in a clinical practice setting, we evaluated zafirlukast in a heterogeneous group of patients who had asthma of different degrees of severity and who were receiving concomitant asthma medications.

METHODS

A total of 3759 patients were enrolled at 924 sites. Patients received zafirlukast 20 mg twice a day for 4 weeks. Pulmonary function was measured twice a day, and overall asthma symptom scores, number of nighttime awakenings, severity of morning asthma symptoms, and beta2-agonist use were recorded daily.

RESULTS

In the efficacy analysis (3207 evaluable patients), all parameters showed statistically significant improvement that continued throughout the 4 weeks of the trial. A total of 71% of patients had improved pulmonary function and 72% had improved asthma symptoms. Improvement was consistent regardless of asthma severity category and regardless of concomitant asthma medication category. More than 70% of both physicians and patients indicated there was clinical improvement in pulmonary measures as well as in asthma symptoms. Common adverse events reported were headache (3.7%), nausea (1.4%), pharyngitis (1.4%), and sinusitis (1.1%).

CONCLUSIONS

Zafirlukast 20 mg twice a day is well tolerated and improves pulmonary function and asthma symptoms, regardless of asthma severity category and regardless of concomitant asthma medication category.

Therapeutic effect of zafirlukast as monotherapy in steroid-naive patients with severe persistent asthma

STUDY OBJECTIVES

We evaluated the efficacy of the leukotriene receptor antagonist zafirlukast (Accolate), 20 mg twice daily, as monotherapy in patients with severe persistent asthma (defined by an FEV1 < 60% of predicted before treatment and frequent night-time symptoms).

DESIGN

Data were analyzed from a subgroup of 261 steroid-naive patients (zafirlukast, n = 149; placebo, n = 112) from four randomized, double-blind, placebo-controlled, 13-week trials with similar experimental designs, entry criteria, and clinical assessments.

PATIENTS

These patients were mostly men (57%) older than 30 years (56%) with pulmonary obstruction, ie, FEV1/FVC ratio < 0.7 (79%), and reversible airway disease demonstrated by a 15% increase in FEV1 after inhaled bronchodilator use.

RESULTS

At end point, patients who received zafirlukast monotherapy had significant (p < 0.05) improvements from baseline, and compared with placebo, in FEV1, morning and evening peak expiratory flow (PEF), daytime asthma symptoms, nighttime awakenings, and beta2-agonist use. A stratified analysis based on the FEV1/FVC ratio showed an interaction between treatment and the amount of airflow obstruction for nighttime awakenings and mornings with asthma. Moreover, 37% of patients in both treatment groups had PEF variability > or = 20% (an indirect measure of airway inflammation). Zafirlukast patients with PEF variability > or = 20% had increases from baseline in the morning and evening PEF of approximately 40 and 11 L/min, respectively. For patients who take zafirlukast and who have a PEF variability of < 20%, the morning and evening PEF increased by 25 and 30 L/min, respectively. Regardless of the degree of PEF variability, zafirlukast significantly (p < 0.05) increased morning and evening PEF compared with placebo.

CONCLUSION

Patients with severe persistent asthma who received zafirlukast as monotherapy had clinically significant improvements across all efficacy measures compared with placebo and significant reductions in PEF variability.

Comparative efficacy and safety of albuterol sulfate Spiros inhaler and albuterol metered-dose inhaler in asthma

STUDY OBJECTIVE

To compare the long-term efficacy and safety of albuterol administration using a Spiros Inhalation System (Dura Pharmaceuticals; San Diego, CA) dry powder inhaler (DPI) and albuterol (Ventolin; Glaxo Wellcome; Research Triangle Park, NC) administration using a metered-dose inhaler (MDI) in patients with asthma.

MATERIALS AND METHODS

This was a phase III, 12-week, randomized, double-blind, double-dummy, placebo-controlled, parallel-group, multicenter study of 283 adolescent and adult patients with mild to moderate asthma. The patients were randomized into one of three treatment groups: the Spiros group, who were given 108 microg/actuation of albuterol sulfate equivalent to 90 microg of albuterol base; the MDI group, who were given 90 microg/actuation of albuterol; and the placebo group.

RESULTS

Over the length of the study, the Spiros and MDI groups were comparable in all FEV1 parameters. Both active treatment groups were superior to the placebo group for each FEV1 parameter at all visits. With the exception of differences at treatment week 0 for the maximum percent change in the FEV1, the duration of effect, and the area under the curve at baseline, there were no statistically significant differences between the Spiros and MDI groups for any FEV1 parameters. Using a repeated-measures analysis, the FEV1 parameters at week 0 for the Spiros group were not statistically significantly different from the parameters at weeks 4, 8, and 12. The same analysis effect at week 0 for the MDI group was greater for maximum percent change in the FEV1 from baseline (weeks 4, 8, and 12) and duration of effect. Adverse events and changes in clinical laboratory values, vital signs, ECG results, and physical examinations were reported with similar incidence in each of the three treatment groups.

CONCLUSION

Both active treatments were superior to the placebo treatment. The Spiros DPI was well tolerated and was as effective as the albuterol MDI in treating patients with moderate asthma.

Comprehensive asthma management: guidelines for clinicians

Asthma is a chronic inflammatory disease characterized by reversible airway obstruction and nonspecific airway hyperreactivity. Asthma is managed in steps according to disease symptoms and severity. Treatment goals are to decrease symptoms, improve pulmonary function, and reduce overall morbidity and the associated cost of medical care. Antiasthma drugs are a key component of asthma management that are classified as either long-term-control medications that control symptoms and prevent disease exacerbations, or quick-relief medications that rapidly relieve airway obstruction and acute asthma symptoms. Several new leukotriene (LT) modulators have been developed that promise to improve asthma control, including LT receptor antagonists montelukast and zafirlukast and the 5-lipoxygenase inhibitor zileuton. Each decreases symptoms and the use of rescue medication, and improves pulmonary function in patients with mild intermittent to moderate persistent asthma.

Zafirlukast improves asthma symptoms and quality of life in patients with moderate reversible airflow obstruction

BACKGROUND

Previous trials demonstrated the effectiveness of the leukotriene receptor antagonist zafirlukast in patients with mild-to-moderate asthma.

OBJECTIVES

We sought to assess the efficacy and safety of zafirlukast and its effect on patients' quality of life (QOL) during a 13-week, double-blind, placebo-controlled, multicenter trial in adults and adolescents with moderate reversible airflow obstruction.

METHODS

Patients (age range, 12 to 68 years) with total daytime asthma symptoms scores of 10 or greater over 7 consecutive days (maximum, 21/wk), FEV1 45% or greater but less than or equal to 80% of predicted value (>/=6 hours after beta2 -agonist), and reversible airway disease were randomized to 20 mg zafirlukast twice daily (nZ = 231) or placebo twice daily (nP = 223). Efficacy was assessed from changes in daytime and nocturnal symptoms, beta2 -agonist use, nasal congestion score, and pulmonary function. QOL was evaluated with a disease-specific Asthma Quality of Life Questionnaire. Safety was determined from adverse event information and clinical laboratory test results.

RESULTS

Zafirlukast was significantly (P <.001) more effective than placebo, with reductions from baseline in the daytime asthma symptoms score (-23%), nighttime awakenings with asthma (-19%), and beta2 -agonist use (-24%) and improvements from baseline in morning (+25 L/min) and evening (+18 L/min) peak expiratory flow rates. Compared with placebo, zafirlukast significantly (P </=.018) improved scores for QOL domains (activity limitations, symptoms, emotional function, and exposure to environmental stimuli) and overall QOL, with a significantly greater proportion of zafirlukast-treated patients demonstrating clinically meaningful improvements (>/=0.5-unit change from baseline; P </=.037). The safety profile of zafirlukast was clinically indistinguishable from that of placebo.

CONCLUSIONS

Zafirlukast is effective and well tolerated and improves QOL in the long-term treatment of patients with moderate reversible airflow obstruction.

Pharmacokinetics of a novel 5-lipoxygenase inhibitor (ABT-761) in pediatric patients with asthma

OBJECTIVE

The pharmacokinetics of an N-hydroxyurea analog, ABT-761 in asthmatic pediatric patients with asthma were investigated.

METHODS

A total of 24 patients were enrolled into this 8-day single- and multiple-dose study. Patients received daily doses of ABT-761 according to their body weight: patients of 20-38 kg received 50 mg; patients >38 kg but < or = 55 kg received 100 mg, and patients >55 kg received 150 mg.

RESULTS

The mean values for the terminal phase t1/2 were 16-17 h after multiple-dose administration. When normalized for body weight, the mean day 8 Cl(f) values for 50-, 100-mg, and 150-mg doses were 0.57 (n=13), 0.51 (n=10), and 0.43 (n=1) ml x min(-1) x kg(-1), respectively, while the mean Vz/f values ranged from 0.75 to 0.77 l x kg(-1). The mean accumulation ratio observed (day 8 to day 1 AUC0-24 ratio) of ABT-761 was approximately 1.7, which is consistent with the t1/2 of this drug. Body weight, age, and body surface area were virtually identical in explaining the variability in dose-normalized Cmax and AUC values (R2=0.61-0.68). The percents of variance explained by these three variables were within a range of 3% for each pharmacokinetic parameter.

CONCLUSIONS

The pharmacokinetics of ABT-761 in children were similar to those previously reported in adults. Body weight, age, or body surface area can be used to provide dosing adjustment for ABT-761 in pediatric patients.

Montelukast once daily inhibits exercise-induced bronchoconstriction in 6- to 14-year-old children with asthma

OBJECTIVE

To determine whether montelukast, a leukotriene receptor antagonist, attenuates exercise-induced bronchoconstriction (EIB) in 6- to 14-year-old children with asthma.

STUDY DESIGN

Double-blind, multicenter, 2-period crossover study. Children (n = 27) with forced expiratory volume in 1 second (FEV1) > or =70% of the predicted value and a fall in FEV1 > or =20% after exercise on 2 occasions. Patients received montelukast (5-mg chewable tablet) or placebo once daily in the evening for 2 days in crossover fashion (at least 4 days between treatment periods). Standardized exercise challenges were performed 20 to 24 hours after the last dose in each period. End points included area above the postexercise percent fall in FEV1 versus time curve (AAC0-60 min), maximum percent fall in FEV1 from pre-exercise baseline, and time to recovery of FEV1 to within 5% of pre-exercise baseline.

RESULTS

Montelukast significantly reduced AAC0-60 min (265 vs 590% x min for montelukast and placebo, respectively, P < or = .05; approximately 59% protection relative to placebo) and the maximum percent fall (18% vs 26% for montelukast and placebo, respectively, P < or = .05). Montelukast treatment resulted in a shorter time to recovery (18 vs 28 minutes for montelukast and placebo, respectively, P = .079).

CONCLUSIONS

Montelukast attenuates EIB at the end of the dosing interval in 6- to 14-year-old children with asthma.

Safety and clinical efficacy of zileuton in patients with chronic asthma

Zileuton, a leukotriene pathway inhibitor used to treat asthma, improves lung function, relieves symptoms, and is well tolerated. The purpose of this 12-month, parallel-group, open-label study was to assess the efficacy of zileuton and evaluate liver function in patients treated with this drug (approximately 2% of patients treated with zileuton in controlled trials had reversible liver enzyme elevations). A total of 2,947 patients at 233 centers in the United States were randomly assigned in a 5:1 ratio to treatment with zileuton plus usual asthma care or usual asthma care alone. Efficacy variables included asthma exacerbations; need for alternative treatment, steroid rescue, emergency care, and hospitalizations; forced expiratory volume in 1 second (FEV1); and asthma symptom scores. The safety evaluation included measurement of alanine aminotransferase levels. Patients treated with zileuton had significantly fewer corticosteroid rescues (P < 0.001), required less emergency care (P < 0.05), had fewer hospitalizations, and had greater increases in FEV1 (P = 0.048). They also had significantly greater improvements in asthma symptoms. Increases in alanine aminotransferase levels to three times or more the upper limit of normal occurred in 4.6% of patients treated with zileuton and 1.1% of those receiving usual care (P < 0.001); most increases occurred during the first 2 to 3 months. Alanine aminotransferase levels decreased to less than two times the upper limit of normal or to baseline levels during zileuton treatment or after drug cessation. Jaundice or chronic liver disease did not develop in any patient. Adding zileuton to the therapeutic regimens of patients with asthma is likely to improve asthma control and lower utilization of healthcare resources.

The responsiveness of disease-specific and generic health measures to changes in the severity of asthma among adults

The objective of the study was to compare the validity of asthma-specific and generic health outcome measures in relation to changes in the severity of asthma and to treatment. Adult patients (n = 142) participating in a randomized placebo-controlled trial at six clinics were assessed at baseline, prior to the withdrawal (placebo) or continuation of treatment with Vanceril and again after 8 weeks. The criterion measures of change in severity included pulmonary function expressed as the percent predicted FEV1, five physician-assessed asthma severity measures (cough, chest tightness, wheezing, shortness of breath and overall condition) and two patient-assessed severity measures (night-time symptoms and overall symptoms). The 8 week change scores were estimated for all generic and specific measures and the results were compared across groups of patients who did and did not change in terms of clinical criteria of disease severity and across treatment groups. The responsiveness of each generic and specific measure was estimated independently using the relative validity (RV) methodology, which compares F-ratios for the mean change scores across measures in analyses of the same comparison groups. RV coefficients estimate how much worse each measure discriminated between comparison groups, relative to the best measure (RV = 1.0). Four standardized asthma-specific measures and a total scale score (based on the Marks questionnaire), an individualized asthma-specific scale measuring limitations in activities most important to each patient (based on the Juniper method) and two newly-developed scales measuring physical and psychosocial symptoms were used as outcome measures, generic health outcome measures included eight functional health and well-being scales as well as the physical and mental health summary scales from the SF-36 health survey. A standardized asthma-specific scale was most valid in discriminating between groups of patients who did and did not change according to all of the clinical criterion variables studied and in discriminating between treated and untreated groups. Different scales performed best, depending on the clinical criterion. The asthma-specific Marks breathlessness scale was significant in all nine comparisons (RV = 0.62-1.0) and was most valid in discriminating between groups in six of nine tests. The overall scale also performed well in all comparisons (RV = 0.58-1.0). The newly-developed physical symptoms scale was significant in discriminating between groups in eight out of nine tests (RV = 0.52-1.0) and was most valid in three of the nine, including the treatment comparison. The psychosocial impact scale discriminated significantly in eight of the nine comparisons (RV = 0.16-0.38), but was less valid than other specific measures. The asthma-specific individualized activities scale discriminated significantly in seven of the nine tests, but performed less well than the other specific measures (RV = 0.21-0.35) and was not significant in the treatment comparison. One or more SF-36 scales discriminated significantly between groups in all nine comparisons. Two of those scales (physical functioning and role-physical) were consistently more valid than the others (RV = 0.17 and 0.58, respectively) and were the only two generic scales that discriminated between groups of patients defined in terms of changes in FEV1 (RV = 0.26-0.58). The SF-36 physical summary scale discriminated significantly between groups in all nine comparisons (RV = 0.19-0.61) and was the most valid generic measure in the treatment comparison (RV = 0.55). The SF-36 mental summary scale was significant only for the two patient-assessed changes in disease severity (RV = 0.31 and 0.32) and for physician-assessed overall severity (RV = 0.12). A comprehensive battery of generic and specific measures is likely to be most useful in understanding the impact of changes in disease severity on the functional health and well-being of adults with asthma, a

Salmeterol improves quality of life in patients with asthma requiring inhaled corticosteroids. Salmeterol Quality of Life Study Group

BACKGROUND

Traditional clinical outcomes have demonstrated that salmeterol improves pulmonary function and reduces asthma symptoms. However, they do not evaluate how patients perceive the effect of therapeutic intervention on day-to-day functioning and well-being.

OBJECTIVE

We sought to evaluate the impact of salmeterol on disease-specific quality of life with the Asthma Quality-of-Life Questionnaire, as well as the efficacy and safety of salmeterol in patients with stable asthma who were symptomatic despite daily use of inhaled corticosteroids.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group study of 506 patients. Patients were treated with 42 microg salmeterol or placebo twice daily for 12 weeks delivered through a metered dose inhaler.

RESULTS

Mean change from baseline in asthma quality-of-life scores was significantly greater (p < or = 0.006) after 12 weeks of treatment with salmeterol compared with placebo ("as-needed" albuterol) in global scores (1.08 vs 0.61) and individual domains (activity limitations, 0.91 vs 0.54; asthma symptoms, 1.28 vs 0.71; emotional function, 1.17 vs 0.65; and environmental exposure, 0.84 vs 0.47). Patients treated with salmeterol experienced significantly greater improvements from baseline to week 12 compared with placebo in FEV1 (0.42 L vs 0.15 L, p < 0.001), morning peak expiratory flow (47 L/min vs 14 L/min, p < 0.001), evening peak expiratory flow (29 L/min vs 11 L/min, p < 0.001), and asthma symptom scores (daytime scores reduced by 0.55 vs 0.30, p < 0.001). Patients treated with salmeterol used significantly less supplemental albuterol (reduced by 3 puffs/day vs 1 puff/day, p < 0.001).

CONCLUSION

Salmeterol provided significantly greater improvement in quality-of-life outcomes in patients whose asthma symptoms are not well controlled with inhaled corticosteroids. These results demonstrate that the benefits of salmeterol are not limited to conventional clinical measures of efficacy.

Dose-related protection of exercise bronchoconstriction by montelukast, a cysteinyl leukotriene-receptor antagonist, at the end of a once-daily dosing interval

The dose-related protective effects of montelukast, a potent and selective cysteinyl leukotriene-receptor antagonist, against exercise-induced bronchoconstriction were investigated in a five-period, randomized, incomplete-block, crossover study with montelukast (0.4, 2, 10, 50 mg) and placebo. The study subjects were 27 nonsmoking, healthy stable patients with asthma (mean forced expiratory volume in 1 second [FEV1], 82.0% predicted) who demonstrated a > or = 20% decrease in FEV1 while beta-agonist was withheld for 6 hours before treadmill exercise. The standard exercise challenge was performed 20 to 24 hours, and again 32 to 36 hours, after the second of two once-daily doses. The effect of oral montelukast on exercise was measured by the area above the postexercise percentage decrease in FEV1 versus time curve from 0 to 60 minutes [AUC(0-60)], the maximal percentage decrease in FEV1 after exercise, and time after maximal decrease to recovery of FEV1 to within 5% of the preexercise baseline. Twenty to 24 hours after administration, montelukast caused dose-related protection, while providing similar protection against exercise-induced bronchoconstriction at the two highest doses. The AUC(0-60) values (mean +/- SD) were 637 +/- 898, 715 +/- 870, 988 +/- 1147, and 927 +/- 968 min. % for 50, 10, 2, and 0.4 mg montelukast, respectively, and 1193 +/- 1097 min. % for placebo (p = 0.003). No important clinical effect was present 36 hours after dosing. Montelukast was generally well tolerated at all dose levels. In conclusion, montelukast caused dose-related protection against exercise-induced bronchoconstriction at the end of a once-daily dosing interval. Protection against exercise-induced bronchoconstriction can be used to determine appropriate dose selection.

Pilot study of bronchodilator response to inhaled albuterol delivered by metered-dose inhaler and a novel dry powder inhaler

BACKGROUND

The metered-dose inhaler is currently one of the most prescribed methods of delivering drugs to the lungs. In the United States, most currently marketed metered dose inhalers use chlorofluorocarbons as the system propellant and require patient breath coordination. These factors lead to the need for a delivery system that is independent of propellants and patient coordination.

OBJECTIVE

To compare the magnitude and time course of bronchodilation between albuterol delivered by Ventolin metered dose inhaler and albuterol sulfate powder (Rotacaps) delivered by a novel dry powder inhaler that generates a respirable drug aerosol over a range of inspiratory flow rates.

METHODS

A single-center, single-dose, randomized, placebo-controlled, partial-blind, 3-way crossover study was conducted in an outpatient asthma Clinical Research Center. Twelve mild to moderate asthmatic patients 12 to 36 years of age participated in this study that involved three treatments, each separated by three to eight days, consisting of 2 puffs (90 micrograms/puff) albuterol by Ventolin metered-dose inhaler, two inhalations (100 micrograms/puff) albuterol sulfate powder (Rotacaps) by dry powder inhaler, and two inhalations (12.5 mg/inhalation) lactose powder by dry powder inhaler. Spirometry, blood pressure, and heart rate were measured at 30 minutes, 15 minutes, and immediately before treatment and then at 15, 30, 45, 60, 90, 120, 180, 240, and 300 minutes after each treatment. Serum potassium and glucose, and electrocardiograms were measured at 30 minutes before, and 30, 60, 90, and 180 minutes after each treatment. Endpoints were compared with analysis of variance.

RESULTS

Five patients (one metered-dose inhaler and four dry powder inhaler) did not respond with > 15% FEV1 increase over baseline within 30 minutes. Metered-dose inhaler and dry powder inhaler mean FEV1 results, respectively, for 11 and 8 responders were 15 minutes in onset, 202.9 and 185.4 minutes in duration, 24.8% and 25.1% maximum change, and 18.6 and 18.2 area-under-FEV1-bronchodilation-curve. Statistical analysis of all patients and responders-only revealed both active treatments to be different from placebo (P = .0018), but not different from each other (P = .1291). No safety endpoints were significantly different among all three treatments (P > .10 for all safety endpoints).

CONCLUSIONS

In this study, the dry powder inhaler safely and effectively delivered a commercially available albuterol sulfate powder (Rotacaps) into human lungs with bronchodilation comparable to Ventolin metered-dose inhaler.

Zafirlukast for symptomatic mild-to-moderate asthma: a 13-week multicenter study. The Zafirlukast Trialists Group

The efficacy of the oral leukotriene-receptor antagonist zafirlukast was assessed as maintenance therapy for patients with mild-to-moderate asthma. A total of 762 patients aged 12 to 76 years were enrolled in a 13-week, multicenter, double-masked, placebo-controlled, parallel-group trial and randomly assigned to receive either zafirlukast (20 mg twice daily) or placebo. Patients were maintained on as-needed beta-agonist therapy throughout the study and had to have a cumulative daytime asthma symptoms score > or = 8 (on a daily scale of 0 to 3) over 7 consecutive days before randomization. Efficacy was assessed by changes in symptoms, beta-agonist use, and pulmonary function. Safety was assessed by adverse experiences, laboratory test results, physical examination, and electrocardiography. Zafirlukast significantly decreased daytime asthma symptoms scores (-26.5%), nighttime awakenings (-19.8%), mornings with asthma (-29.0%), and beta-agonist use (-22.3%) and significantly increased morning peak expiratory flow rate (6.9%) and forced expiratory volume in 1 second (6.3%) compared with placebo. Changes in symptoms, beta-agonist use, and pulmonary function occurred within 2 days of zafirlukast treatment and continued throughout the trial. Zafirlukast was well tolerated. Pharyngitis and headache were the most common adverse events, occurring with similar frequency in both the zafirlukast and placebo groups. No clinically significant changes were observed in laboratory test results, findings on physical examination, or electrocardiographic findings. We conclude that zafirlukast produces early and sustained effects in the treatment of mild-to-moderate asthma.

Special considerations in the treatment of seasonal allergic rhinitis in adolescents: the role of antihistamine therapy

The symptoms of seasonal allergic rhinitis often develop during adolescence. Teen-age students with seasonal allergic rhinitis may experience decreased academic performance and productivity from the disease or because of the sedative effects of some antihistamines. The pharmacologic effects of nonsedating second-generation antihistamines are compared with those of classical antihistamines. The effects of antihistamines on sedation and motor and cognitive function are discussed. The role of antiinflammatory agents, decongestants, and combination products is reviewed. Potential drug interactions must be considered along with factors such as drug-induced weight gain and the use of antihistamines in potentially pregnant patients in selecting appropriate antihistamine therapy for adolescent patients.

Efficacy and safety of inhaled bitolterol mesylate via metered-dose inhaler in children with asthma

BACKGROUND

There have been numerous studies in asthmatic adults demonstrating the efficacy and safety of bitolterol mesylate metered-dose inhaler; however, only one additional study has examined bitolterol metered-dose inhaler in pediatric asthma.

OBJECTIVE

To establish the safety and effectiveness of bitolterol mesylate metered-dose inhaler at one, two, and three inhalations in pediatric asthmatic patients 4 to 12 years of age.

METHODS

A multicenter, double-blind, randomized, crossover, placebo-controlled, dose-ranging study. Forty-six patients were evaluated in three centers. Patients were stratified by age, 4 to 6, 7 to 9, 10 to 12 years at each center. One, two, or three inhalations were administered along with an additional double-blind, randomized, placebo dose. Bronchodilation was defined as a 15% or greater increase in FEV1 over baseline. Onset, maximum improvement, and duration of action were obtained for each patient. Serial pulse rate, blood pressure, and respiratory rate determinations were obtained for each patient.

RESULTS

Onset within five minutes occurred in 56.6% to 71% of patients, depending on the dose. Mean maximum improvement, which was dose dependent, overall ranged from 28.2% to 40.3% with a peak response in 66.7 to 69.8 minutes. In direct relationship of magnitude with regard to dose of bitolterol was observed, (P < .001). A significant correlation, r = .732, in response between bronchodilation and baseline FEV1 was observed (P < .001). Median duration of action ranged from three to four hours in responding patients across all doses. Up to 31% of patients had durations greater than eight hours after three inhalations. Adverse effects were reported in five of 46 patients for all doses with mild transient tremor occurring in two patients, 4.3%. Also, there was little effect on pulse rate, 2.2%.

CONCLUSION

Bitolterol is an effective bronchodilator with durations of activity up to eight hours and minimal adverse effects in children.

Safety of salmeterol in the maintenance treatment of asthma

BACKGROUND

Salmeterol is the first long-acting inhaled beta 2-agonist available in the US for the maintenance treatment of asthma.

OBJECTIVE

To compare the safety of salmeterol with that of the short-acting beta 2-agonist albuterol.

METHODS

Two identically designed, prospective, randomized, double-blind, parallel studies were conducted comparing salmeterol 42 micrograms twice daily, albuterol 180 micrograms four times daily, and placebo over 12 weeks in 556 patients (12 to 73 years old) with mild-to-moderate chronic asthma. Patients in each treatment group could use albuterol as needed to control acute symptoms.

RESULTS

The incidence of potentially drug-related adverse events was similar among the treatment groups (range: 22% to 23%), with headache being the most commonly reported (range: 9% to 10%). No deaths occurred during the studies. Concomitant use of > 4 puffs of supplemental albuterol per day in the salmeterol group produced no increase in the incidence of adverse events either in general or of a cardiovascular nature. There were no statistically significant differences among treatment groups or clinically significant changes from pretreatment values in mean pulse rate, systolic/diastolic blood pressure, or clinical laboratory values after 12 weeks. There were no clinically significant differences among groups in heart rates nor were there differences in the frequency of supraventricular or ventricular ectopic beats during 24-hr Holter monitoring. The frequency of asthma exacerbations was lowest among patients receiving salmeterol (and highest among those who received placebo), and this rate did not increase over the 12 weeks. Asthma exacerbations were treated successfully with nebulized albuterol (2.5 mg), with no evidence of any increased risk of cardiovascular events.

CONCLUSIONS

Salmeterol 42 micrograms twice daily is well-tolerated in patients with asthma, having a similar safety profile as that of albuterol 180 micrograms inhaled four times daily or placebo (plus as-needed albuterol). Concomitant use of albuterol, either by MDI or nebulization, did not affect the safety of salmeterol. Extensive cardiovascular monitoring revealed no significant cardiovascular adverse effects or arrhythmogenic effects associated with salmeterol over 12 weeks.

Prolonged effect of inhaled salmeterol against exercise-induced bronchospasm

Physical exercise is a common trigger for bronchial asthma. We evaluated the preventive effect on exercise-induced bronchospasm (EIB) of a single 42 micrograms dose of salmeterol, a uniquely long-acting inhaled bronchodilator, and compared salmeterol with 180 micrograms albuterol in two independent, randomized, double-blind, placebo-controlled studies involving 161 subjects. Three exercise challenges were conducted over 12 h, and bronchoconstriction following the serial challenges was assessed as change in FEV1 compared with predose values. The mean maximal percentage decrease in FEV1 after the three exercise challenges was 5% at 0.5 h, 8% at 5.5 h, and 13% at 11.5 h postdose in the salmeterol group compared with 7, 25, and 27%, respectively, in the albuterol group and 27, 27, and 26%, respectively, in the placebo group (p < 0.001, overall treatment difference). Albuterol provided complete protection against EIB (defined as < 10% decrease in FEV1 compared with predose values) only after the first exercise challenge, but salmeterol continued to provide complete protection in the majority of subjects after each exercise challenge: 80% (44 of 55) at 0.5 h, 70% (37 of 53) at 5.5 h, and 55% (29 of 53) at 11.5 h. Electrocardiographic monitoring revealed no clinically significant changes in any treatment group 15 and 30 min following each exercise challenge. In summary, these data demonstrate that salmeterol is effective against EIB and that a single 42 micrograms dose can prevent EIB for up to 12 h.

A 1-week dose-ranging study of inhaled salmeterol in patients with asthma

STUDY OBJECTIVE

A dose-ranging study was conducted to evaluate the efficacy and safety of a new long-acting, selective beta 2-adrenoceptor agonist, salmeterol.

DESIGN

Adolescents and adults (N = 160) with mild-to-moderate asthma received salmeterol (10.5, 21, 42, or 84 micrograms) or placebo by metered-dose inhaler twice daily for 1 week. Twelve-hour serial spirometry measurements were performed on the first and last days of treatment, and patients recorded their peak expiratory flow (PEF) twice daily on diary cards.

RESULTS

On day 1, salmeterol produced greater bronchodilation than placebo (p = 0.001), and both the 42-micrograms and 84-micrograms doses of salmeterol were significantly more effective in improving FEV1 responses than the two lower doses of salmeterol (p < 0.05). After 1 week of treatment, all but the 21-micrograms dose of salmeterol remained statistically superior to placebo (p < 0.01), but significant differences between salmeterol doses were no longer evident, despite an apparent dose-response effect. Only the 42-micrograms and 84-micrograms doses of salmeterol sustained bronchodilation for 12 h in the majority of patients at both treatment days. The degree of improvement in morning and evening PEF was also found to be dose related. There was no significant difference among treatment groups in the overall incidence of adverse events; however, pharmacologically predictable events (eg, tremor) occurred significantly more often with salmeterol, 84 micrograms.

CONCLUSIONS

Salmeterol, 42 micrograms, was similar in efficacy to 84 micrograms but was associated with a lower incidence of adverse events. Salmeterol, 42 micrograms twice daily, is a safe and effective dosage for patients with mild-to-moderate asthma who are persistently symptomatic and require maintenance bronchodilator therapy.

Multicenter dose-ranging study of bitolterol mesylate solution for nebulization in children with asthma

This open-label, placebo-controlled study was undertaken to assess the safety and effectiveness of bitolterol mesylate in pediatric asthma patients. Bitolterol mesylate was administered in increasing doses of 0.5 to 3.5 mg by continuous-flow nebulization on separate days to children 4 to 12 years of age. Pulmonary function tests and vital signs were measured before and for up to eight hours after each treatment. Bronchodilation was defined as a > or = 15% increase in FEV1 over baseline. Onset, magnitude, and duration of bronchodilation all showed general dose-related improvements. Onset of bronchodilation occurred within five minutes in 66% to 82% of all treatments. The mean maximum percent increase in FEV1 ranged from 35% to 52% for all doses. Median durations of bronchodilation in responding patients ranged from four and one tenth to more than eight hours. Bitolterol was well-tolerated with all adverse effects being mild to moderate in severity and transient in nature. Although the incidence of cough, increased pulse rate, and tremor were relatively low, they did increase slightly with the 2.5- and 3.5-mg doses. No significant clinical laboratory or electrocardiographic findings were noted. We conclude that doses of 1.0 and 1.5 mg bitolterol mesylate administered by continuous-flow nebulization are safe, effective, and well-tolerated for the treatment of asthma in pediatric patients.

The effect of inhibition of 5-lipoxygenase by zileuton in mild-to-moderate asthma

OBJECTIVE

To evaluate the effectiveness of inhibiting the formation of the 5-lipoxygenase products of arachidonic acid by the 5-lipoxygenase inhibitor zileuton in the treatment of mild-to-moderate asthma.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

University hospitals and private allergy and pulmonary practices.

PATIENTS

A total of 139 persons with asthma who had a forced expiratory volume in 1 second (FEV1) of 40% to 75% of the predicted value and who were not being treated with inhaled or oral steroids.

INTERVENTION

Zileuton, 2.4 g/d or 1.6 g/d, or placebo for 4 weeks.

MEASUREMENTS

Airway function, beta-agonist use, and symptoms; inhibition of 5-lipoxygenase assessed by measurement of urinary leukotriene E4 (LTE4).

RESULTS

Zileuton produced a 0.35-L (95% CI, 0.25 to 0.45 L) increase in the FEV1 within 1 hour of administration (P < 0.001 compared with placebo), equivalent to a 14.6% increase from baseline. After 4 weeks of zileuton therapy, airway function and symptoms improved, with the greatest improvements occurring in the 2.4 g/d group: This group's FEV1 increased by 0.32 L (CI, 0.16 to 0.48 L), a 13.4% increase, compared with a 0.05-L (CI, -0.10 to 0.20 L) increase in patients taking placebo (P = 0.02). Symptoms and frequency of beta-agonist use also decreased with zileuton, 2.4 g/d. The mean urinary LTE4 level decreased by 39.2 pg/mg creatinine (CI, 18.1 to 60.4 pg/mg creatinine) and 26.5 pg/mg creatinine (CI, 6.6 to 46.5 pg/mg creatinine) in the 2.4 g/d and 1.6 g/d groups, respectively, compared with a slight increase in the placebo group (P = 0.007 and P = 0.05). No difference was noted in the number of adverse events among treatment groups.

CONCLUSIONS

Inhibition of 5-lipoxygenase can improve airway function and decrease symptoms and medication use in patients with asthma, suggesting that this inhibition can be useful therapy for asthma. Also, 5-lipoxygenase products may mediate part of the baseline airway obstruction in patients with mild-to-moderate asthma.