Comparative efficacy of inhaled medications (ICS/LABA, LAMA, LAMA/LABA and SAMA) for COPD: a systematic review and network meta-analysis

PURPOSE

To assess the comparative efficacy of short-acting muscarinic antagonists (SAMAs), long-acting muscarinic antagonists (LAMAs), LAMA in combination with long-acting beta-agonists (LABAs; LAMA/LABAs) and inhaled corticosteroids (ICS) in combination with LABA (ICS/LABAs) for the maintenance treatment of COPD.

MATERIALS AND METHODS

We systematically reviewed 74 randomized controlled trials (74,832 participants) published up to 15 November 2017, which compared any of the interventions (SAMA [ipratropium], LAMA [aclidinium, glycopyrronium, tiotropium, umeclidinium], LAMA/LABA [aclidinium/formoterol, indacaterol/glycopyrronium, tiotropium/olodaterol, umeclidinium/vilanterol] and ICS/LABA [fluticasone/vilanterol, budesonide/formoterol, salmeterol/fluticasone]) with each other or with placebo. A random-effects network meta-analysis combining direct and indirect evidence was conducted to examine the change from baseline in trough FEV1, transition dyspnea index, St George's Respiratory Questionnaire and frequency of adverse events at weeks 12 and 24.

RESULTS

Inconsistency models were not statistically significant for all outcomes. LAMAs, LAMA/LABAs and ICS/LABAs led to a significantly greater improvement in trough FEV1 compared with placebo and SAMA monotherapy at weeks 12 and 24. All LAMA/LABAs, except aclidinium/formoterol, were statistically significantly better than LAMA monotherapy and ICS/LABAs in improving trough FEV1. Among the LAMAs, umeclidinium showed statistically significant improvement in trough FEV1 at week 12 compared to tiotropium and glycopyrronium, but the results were not clinically significant. LAMA/LABAs had the highest probabilities of being ranked the best agents in FEV1 improvement. Similar trends were observed for the transition dyspnea index and St George's Respiratory Questionnaire outcomes. There were no significant differences in the incidences of adverse events among all treatment options.

CONCLUSION

LAMA/LABA showed the greatest improvement in trough FEV1 at weeks 12 and 24 compared with the other inhaled drug classes, while SAMA showed the least improvement. There were no significant differences among the LAMAs and LAMA/LABAs within their respective classes.

Comparative safety and effectiveness of long-acting inhaled agents for treating chronic obstructive pulmonary disease: a systematic review and network meta-analysis

OBJECTIVE

To compare the safety and effectiveness of long-acting β-antagonists (LABA), long-acting antimuscarinic agents (LAMA) and inhaled corticosteroids (ICS) for managing chronic obstructive pulmonary disease (COPD).

SETTING

Systematic review and network meta-analysis (NMA).

PARTICIPANTS

208 randomised clinical trials (RCTs) including 134,692 adults with COPD.

INTERVENTIONS

LABA, LAMA and/or ICS, alone or in combination, versus each other or placebo.

PRIMARY AND SECONDARY OUTCOMES

The proportion of patients with moderate-to-severe exacerbations. The number of patients experiencing mortality, pneumonia, serious arrhythmia and cardiovascular-related mortality (CVM) were secondary outcomes.

RESULTS

NMA was conducted including 20 RCTs for moderate-to-severe exacerbations for 26,141 patients with an exacerbation in the past year. 32 treatments were effective versus placebo including: tiotropium, budesonide/formoterol, salmeterol, indacaterol, fluticasone/salmeterol, indacaterol/glycopyrronium, tiotropium/fluticasone/salmeterol and tiotropium/budesonide/formoterol. Tiotropium/budesonide/formoterol was most effective (99.2% probability of being the most effective according to the Surface Under the Cumulative RAnking (SUCRA) curve). NMA was conducted on mortality (88 RCTs, 97 526 patients); fluticasone/salmeterol was more effective in reducing mortality than placebo, formoterol and fluticasone alone, and was the most effective (SUCRA=71%). NMA was conducted on CVM (37 RCTs, 55,156 patients) and the following were safest: salmeterol versus each OF placebo, tiotropium and tiotropium (Soft Mist Inhaler (SMR)); fluticasone versus tiotropium (SMR); and salmeterol/fluticasone versus tiotropium and tiotropium (SMR). Triamcinolone acetonide was the most harmful (SUCRA=81%). NMA was conducted on pneumonia occurrence (54 RCTs, 61 551 patients). 24 treatments were more harmful, including 2 that increased risk of pneumonia versus placebo; fluticasone and fluticasone/salmeterol. The most harmful agent was fluticasone/salmeterol (SUCRA=89%). NMA was conducted for arrhythmia; no statistically significant differences between agents were identified.

CONCLUSIONS

Many inhaled agents are available for COPD, some are safer and more effective than others. Our results can be used by patients and physicians to tailor administration of these agents.

PROTOCOL REGISTRATION NUMBER

PROSPERO # CRD42013006725.

Identification and characterization of m1 selective muscarinic receptor antagonists1

A series of esters of 1,4-disubstituted tetrahydropyridine carboxylic acids (I) has been synthesized and characterized as potential m1 selective muscarinic receptor antagonists. The affinity of these compounds for the five human muscarinic receptor subtypes (Hm1-Hm5) was determined by the displacement of [3H]-NMS binding using membranes from transfected Chinese hamster ovarian cells. One of the most potent and selective compounds of this series is an analogue of I [11, R1 = (CH2)5CH3], which has an IC50 value of 27.3 nM at the m1 receptor and possesses 100-fold (m2), 48-fold (m3), 74-fold (m4), and 19-fold (m5) selectivities at the other receptors. Thus, this analogue appears to be more selective on the basis of binding than the prototypical m1 antagonist, pirenzepine. Functional data, such as the inhibition of carbachol-stimulated phosphatidylinositol hydrolysis, on selected analogues confirmed the muscarinic antagonistic properties of this chemical series.

Selective muscarinic receptor agonists and antagonists

Muscarinic receptors are composed of a family of four subtypes each of which can be distinguished pharmacologically and structurally. The physiological role of each subtype in the central and peripheral nervous systems remains to be clarified, due, in part, to a lack of agonists and antagonists with adequate subtype selectivity. Nonetheless, several agonists with functional selectivity for M1 receptors are now in advanced clinical evaluation for Alzheimer's disease, while selective M1/M3 antagonists may prove useful in the treatment of disorders of smooth muscle function. These novel compounds thus provide an advance over earlier therapeutics with which the clinical efficacy was compromised by the side effect profile. This review attempts to assess novel, selective agonists and antagonists, both in terms of their use in defining muscarinic receptor subtypes and their potential clinical utility.

Pharmacological characterization of muscarinic receptors mediating acetylcholine-induced contraction and relaxation in rabbit intrapulmonary arteries

Rabbit pulmonary arteries exhibit a biphasic response to acetylcholine consisting of an endothelium-dependent contraction in tissues at resting tone and an endothelium-dependent relaxation in vessels with elevated tone. Each response was studied separately by treating the arteries with inhibitors of nitric oxide synthase to block the relaxant response or with inhibitors of cyclooxygenase to inhibit the contractile response. In the present study, experiments in isolated pulmonary arteries were undertaken to characterize the muscarinic receptor subtypes mediating the two separate responses by utilizing subtype-selective antagonists and determining pA2 values of the antagonists through Schild analysis. Both the relaxant and the contractile responses were inhibited most potently by atropine and by the M3-selective antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide. The pA2 values for inhibition of the contractile and relaxant responses were 9.44 and 8.79 for atropine and 8.92 and 9.29 for 4-diphenylacetoxy-N-methylpiperidine methiodide, respectively. The M1-selective antagonist pirenzepine and the M2-selective antagonist (11-([2-[(diethylamino)methyl]-1-piperidinyl]- acetyl)-5, 11-dihydro-6H-pyrido[2,3-b][1,4]-benzodiazepine-6-one) displayed much lower affinities for the muscarinic receptors mediating these responses. The pA2 values for inhibition of the contractile and relaxant responses were 6.77 and 6.74 for pirenzepine and 6.06 and 5.70 for (11-([2-[(diethylamino)methyl]-1-piperidinyl] acetyl)-5, 11-dihydro-6H-pyrido[2,3-b][1,4]-benzodiazepine-6-one), respectively.