Theophylline. Current thoughts on the risks and benefits of its use in asthma

Comparison of salmeterol/fluticasone propionate (FP) combination with FP+sustained release theophylline in moderate asthma patients

OBJECTIVES

To compare the efficacy and safety of the salmeterol/fluticasone propionate combination product with concurrent sustained release theophylline plus fluticasone propionate in adult Japanese patients with persistent asthma.

DESIGN

Multicentre, randomised, double-blind, double-dummy, parallel-group study.

PATIENTS AND INTERVENTIONS

Three hundred and eighty-three asthmatic patients receiving sustained release theophylline 200-400mg/day entered the study and were randomised to receive either salmeterol/fluticasone propionate combination (SFC) 50microg/250microg+1 placebo tablet, fluticasone propionate 250microg+1 sustained release theophylline 200mg (SR-T+FP), twice daily for 8 weeks.

RESULTS

The adjusted mean change morning peak expiratory flow (PEF) over 8 weeks was 29.8L/min in the SFC group and 16.3L/min in the SR-T+FP group, with a treatment difference of 13.4L/min (p=0.0004). SFC improved evening PEF, FEV1, V50 and V25 at the completion of treatment to a greater extent than SR-T+FP (all p<0.05). A higher percentage of patients on SFC were symptom free (p=0.0286) and rescue free (ns) than those on SR-T+FP. There was not a statistically significant difference between treatments in symptom scores. Both treatments were well tolerated.

CONCLUSIONS

The finding that SFC was associated with greater improvements in lung function than SR-T+FP, a commonly employed treatment for asthmatic patients in Japan, suggests that SFC should be the preferred therapeutic option in these patients.

Synthesis and bronchodilator activity of new quinazolin derivative

Taking lead from a naturally occurring quinazolin vasicine, a number of compounds were developed and evaluated for bronchodilator and anti-allergic activities. One of these compounds was 2,4-diethoxy-6,7,8,9,10,12-hexahydroazepino[2,1-b]quinazolin-12-one, hereinafter named 95-4, exhibited marked bronchodilator activity evaluated on contracted trachea or constricted tracheo-bronchial tree. On intestinal smooth muscle too it showed relaxant effect. Tracheal relaxant effect was not found to be mediated through beta-adrenoceptors. Cumulative dose-response study with acetylcholine and histamine indicated for its non-specific direct effect on smooth muscles. 95-4 was found to be more potent than theophylline and less to that of salbutamol on dose basis. Tested by a number of experimental models, it was found devoid of anti-allergic activity. It was also found to be free from any adverse effect. 95-4 due to its marked bronchial muscle relaxant effect can find use in conditions associated with spasm of bronchial muscles.

Montelukast or salmeterol combined with an inhaled steroid in adult asthma: design and rationale of a randomized, double-blind comparative study (the IMPACT Investigation of Montelukast as a Partner Agent for Complementary Therapy-trial)

Asthma patients who continue to experience symptoms despite taking regular inhaled corticosteroids represent a management challenge. Leukotrienes play a key role in asthma pathophysiology, and since pro-inflammatory leukotrienes are poorly suppressed by corticosteroids it seems rational to add a leukotriene receptor antagonist (LTRA) when a low to moderate dose of inhaled corticosteroids does not provide sufficient disease control. Long acting beta2-agonist (LABA) treatment represents an alternative to LTRAs and both treatment modalities have been shown to provide additional disease control when added to corticosteroid treatment. To compare the relative clinical benefits of adding either a LTRA or a LABA to asthma patients inadequately controlled by inhaled corticosteroids, a randomized, double-blind, multi-centre, 48-week study will be initiated at approximately 120 centres throughout Europe, Latin America, Middle East, Africa and the Asia-Pacific region in early 2000. The study will compare the oral LTRA montelukast with the inhaled LABA salmeterol, each administered on a background of inhaled fluticasone, on asthma attacks, quality of life, lung function, eosinophil levels, healthcare utilization, and safety, in approximately 1200 adult asthmatic patients. The requirements for study enrollment include a history of asthma, FEV1 or PEFR values between 50% and 90% of the predicted value together with > or = 12% improvement in FEV1 after beta-agonist administration, a minimum pre-determined level of asthma symptoms and daily beta-agonist medication. The study will include a 4-week run-in period, during which patients previously taking inhaled corticosteroids are switched to open-label fluticasone (200 microg daily), followed by a 48-week double-blind, treatment period in which patients continuing to experience abnormal pulmonary function and daytime symptoms are randomized to receive montelukast (10 mg once daily) and salmeterol placebo, or inhaled salmeterol (100 microg daily) and montelukast placebo. All patients will continue with inhaled fluticasone (200 microg daily). During the study, asthma attacks, overnight asthma symptoms, and morning peak expiratory flow rate will be assessed using patient diary cards; quality of life will also be assessed using an asthma-specific quality-of life questionnaire. The results of this study are expected to provide physicians with important clinical evidence to help them make a rational and logical treatment choice for asthmatic patients experiencing breakthrough symptoms on inhaled corticosteroids.

The efficacy and safety of salmeterol compared to theophylline: meta-analysis of nine controlled studies

The aim of this study was to compare the efficacy and safety of salmeterol vs theophylline in asthma management using meta-analysis of clinical trials. Nine clinical studies, containing a total of 1330 patients, met meta-analysis inclusion criteria: randomized, controlled study, minimum 2-week treatment duration with either salmeterol or theophylline. The main outcome measurements were morning and evening peak expiratory flow rate (PEFR), morning and evening symptom scores, use of salbutamol as rescue medication, and withdrawal from treatment for any cause. During the second week of treatment, salmeterol patients had a 10 l min-1 greater increase in mean morning PEFR from baseline than theophylline patients (P < 0.001). Similarly, in the second week, the increase in mean evening PEFR from baseline observed with salmeterol was significantly greater (P < 0.01) than that observed with theophylline. Salmeterol also produced a significantly greater increase in mean morning and evening PEFR than theophylline at weeks 3 and 4. Patients receiving salmeterol were free from daytime symptoms for a mean of 51% of days in the second week compared to 39% for theophylline patients (P < 0.001). Salmeterol patients experienced a mean of 63% symptom-free nights compared to 52% for theophylline patients (P < 0.001). Rescue medication with salbutamol was not required on 49% of days for salmeterol patients and 34% of days for theophylline patients. All results were maintained in the third and fourth weeks of treatment. Withdrawal and incidence of adverse events leading to withdrawal were significantly less frequent in patients receiving salmeterol (P < 0.001). Thus, this meta-analysis suggests that salmeterol has a superior safety and efficacy profile to theophylline in the management of symptoms of chronic asthma.

Salmeterol versus theophylline in the treatment of asthma

BACKGROUND

Although theophylline is recommended by current guidelines for the management of asthma in patients with persistent symptoms, theophylline has a narrow therapeutic index, requiring individual dose titration and regular monitoring of serum theophylline concentrations to avoid adverse effects.

OBJECTIVE

To compare the inhaled long-acting bronchodilator, salmeterol, with the oral bronchodilator, theophylline, in the maintenance treatment of asthma.

METHODS

In two multicenter, randomized, double-blind, double-dummy, placebo-controlled, parallel-group studies, patients received salmeterol aerosol 42 micrograms, extended-release theophylline capsules, or placebo twice daily for 12 weeks.

RESULTS

Of 638 adult and adolescent patients with moderate asthma who entered the prebaseline theophylline titration period, 154 were withdrawn prior to randomization (71 due to theophylline-related adverse effects); 484 patients comprised the intent-to-treat population. The mean serum theophylline concentration measured approximately seven hours postdose during the titration period in the theophylline group was 12.7 mg/L (70 mumol/L). The same dose during the treatment period resulted in a mean serum theophylline concentration between 7.6 to 7.9 mg/L (42-44 mumol/L) when measured approximately 12 hours postdose. Salmeterol was significantly more effective than theophylline or placebo in improving mean morning PEF over the entire 12 weeks (P < or = .02). Mean predose FEV1 improved significantly with salmeterol compared with placebo (P < .001); there was no difference between theophylline and placebo. Salmeterol was also significantly more effective than theophylline or placebo (P < .02) in improving asthma symptoms, reducing nighttime awakenings, and reducing the daily use of albuterol. After 12 weeks of treatment, patients in the salmeterol group expressed significantly greater overall satisfaction with their asthma medication than did patients who received theophylline (P < .01). Patients in the theophylline group experienced more gastrointestinal adverse events than did patients in the salmeterol group (P < .05).

CONCLUSION

Salmeterol, 42 mg twice daily, was better tolerated and significantly more effective than extended-release theophylline twice daily in the maintenance treatment of asthma.

Efficacy and safety of salmeterol in childhood asthma

In children with asthma, twice daily administration of salmeterol 25 micrograms, salmeterol 50 micrograms and salbutamol 200 micrograms were compared in two, 3-month, double-blind, parallel group studies, one using metered dose inhalers (MDIs), the other using dry powder inhalers (Diskhaler, DPIs). Both studies were continued for a further 9 months during which time exacerbation rates, lung function at the clinic and adverse events were monitored. Similarities in design and methodology of the two studies justified a combined analysis. Eight hundred and forty-seven asthmatic children aged between 4 and 16 (mean 10.1) years, requiring inhaled beta 2-agonist treatment were randomised to treatment. After a 2 week run-in when all bronchodilator therapy was withdrawn, 279 patients received salmeterol 25 micrograms bd, 290 patients salmeterol 50 micrograms bd and 278 patients salbutamol 200 micrograms bd. After 3 months' treatment the change from baseline in daily morning and evening peak expiratory flow (PEF) was significantly greater with salmeterol 50 micrograms bd than with salbutamol 200 micrograms bd (P < 0.001). Salmeterol 50 micrograms bd was also significantly better than salmeterol 25 micrograms bd at improving mean morning PEF (P = 0.017) but both treatments had a similar effect on evening PEF. Analysis of variance showed an interaction between baseline PEF less than 100% predicted normal value and treatment outcome. Analysis of this sub-set of patients with lower lung function revealed similar results to the total population although the improvements in PEF from baseline were greater. Data from both studies, showed that the improvement in lung function was maintained throughout 12 months' treatment. Patients receiving salmeterol 50 micrograms bd had significantly more symptom-free nights (P < 0.01) and a higher percentage of rescue bronchodilator-free days (P = 0.01). The incidence of asthma exacerbations was evenly distributed between the three treatment groups and there was no evidence of any change in the rate of occurrence of exacerbations over the 12 month period. Adverse events were no different across treatment groups or across age groups and were primarily related to the patients' disease state.

CONCLUSION

Salmeterol 50 micrograms bd is the appropriate dose for the treatment of children with mild to moderate asthma.

A 4-week comparison of salmeterol and terbutaline in adult asthma

This was a 4-week, open-label, parallel-group study designed to compare the efficacy and safety of the long-acting inhaled bronchodilator, salmeterol, with the established inhaled bronchodilator, terbutaline, in the treatment of patients with mild to moderate asthma. A total of 243 adult patients was randomized to receive treatment with either salmeterol 50 micrograms bd via a Diskhaler (Glaxo) inhaler (n = 121) or terbutaline 500 micrograms qds via a reservoir powder inhaler device (n = 122). Apart from all bronchodilator treatment which was withdrawn at the start of the run-in period and replaced by inhaled salbutamol to be used as required for symptom relief, all concurrent medications were kept constant throughout the study. Salmeterol produced a significantly greater increase in mean morning peak expiratory flow (PEF) than terbutaline (difference in adjusted means after treatment = 28 l/min; 95% CI = 19-37 l/min; P < 0.001). Likewise, the increase in mean evening PEF was significantly greater following treatment with salmeterol than with terbutaline (difference in adjusted means = 9 l/min; 95% CI = 0-17 l/min; P = 0.045). Salmeterol was associated with a significant reduction in diurnal variation in PEF by comparison with terbutaline (difference in adjusted means = -18 l/min; 95% CI = -24, -12 l/min; P < 0.001). Significant improvements with salmeterol by comparison with terbutaline were also observed in daytime and night-time asthma scores, percentage of symptom-free days and nights, use of additional inhaled bronchodilator, and percentage of days and nights when no additional inhaled bronchodilator was needed.(ABSTRACT TRUNCATED AT 250 WORDS)

Pilgrim's progress: the effect of salmeterol in older children with chronic severe asthma

Twenty-four children aged 12-17 years entered a randomized, double-blind placebo-controlled study investigating the use of salmeterol in chronic severe asthma. In addition to their usual medication, the children were given either placebo or 100 micrograms salmeterol b.d. by dry powder inhalation. Treatment was continued throughout one term at a residential school for asthma. Symptom scores, peak expiratory flow rates, spirometry and quality-of-life scores were compared between the two treatment groups. One child withdrew during the run-in period. Twelve pupils received placebo and 11 pupils received salmeterol. There were consistent improvements in favour of salmeterol, reaching statistical significance for morning and evening peak flow rates and spirometry when measured on four occasions during the study period. There were no medication-related adverse events recorded and no pulse rate changes. Salmeterol (100 micrograms b.d.) is well tolerated and efficacious in older children with chronic severe asthma.

A double-blind comparison of inhaled budesonide, long-acting theophylline, and their combination in treatment of nocturnal asthma

In 61 patients with nocturnal asthma, the effects of budesonide, an inhaled steroid (Pulmicort; 200 micrograms twice daily), long-acting theophylline (Theodur; 200 mg twice daily), and their combination were compared. After a 2-week placebo run-in period, the patients were entered into double-blind, crossover periods of 3 weeks. Patients were allowed to use inhaled beta 2-agonists as required throughout the study. Morning and evening peak expiratory flow rate (PEFR) (percentage of predicted normal +/- SEM) was significantly higher during the budesonide (morning 77 +/- 1%; evening 80 +/- 1%) and combination therapy (morning 79 +/- 1%; evening 81 +/- 1%) than the theophylline treatment (morning 74 +/- 1%; evening 76 +/- 1%; P < 0.01, respectively). Significantly fewer sleep disturbances and fewer nighttime inhalations of beta 2-agonists were required during budesonide and combination therapy than theophylline treatment. No statistically significant differences were seen between combined therapy and budesonide alone. Budesonide, an inhaled steroid, was significantly better than the bronchodilator, theophylline, in controlling nocturnal asthma, but no additional improvement in efficacy was seen when the drugs were used in combination.

The efficacy and tolerability of inhaled salmeterol and individually dose-titrated, sustained-release theophylline in patients with reversible airways disease

In a double-blind, double-dummy, cross-over, multicentre study, 141 patients with moderate reversible airways disease were randomized to receive either 50 micrograms salmeterol via a metered dose inhaler or individually dose-titrated oral theophylline, both twice daily for a 2-week period. Just over half (n = 77) the patients had received theophylline before, but 64 patients were new to theophylline therapy. Efficacy was based on lung function data and symptom scores. Salmeterol produced significantly higher increase in mean morning peak expiratory flow (PEF) of 161 min-1 (P < 0.001; 95% Confidence Interval (CI); 8-241 min-1) and mean evening PEF of 151 min-1 (p < 0.001; 95% CI; 7-221 min-1) compared with theophylline therapy. Further analysis of the data revealed that the increase in PEF with salmeterol compared with theophylline was highest in a sub-group of patients new to theophylline therapy. Patients on salmeterol had significantly less night-time awakenings than those on theophylline (P = 0.011) and significantly less daytime symptoms (P = 0.017). There was also a significant increase in the number of nights (P = 0.013) and days (P < 0.001) on salmeterol when no additional salbutamol was required compared with theophylline. Theophylline produced a higher incidence of adverse events compared with salmeterol. The results of this study show that inhaled salmeterol is more effective and better tolerated than individually dose-titrated oral theophylline over a 2-week study period in patients with moderate asthma.