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The effects of calcitriol treatment in glucocorticoid-resistant asthma

2014; Elsevier BV; Volume: 133; Issue: 6 Linguagem: Inglês

10.1016/j.jaci.2014.03.015

1097-6825

Alexandra M. Nanzer, Emma S. Chambers, Kimuli Ryanna, Anna Freeman, Grainne Colligan, David F. Richards, Peter Timms, Adrian R. Martineau, Chris Griffiths, Christopher J. Corrigan, Catherine M. Hawrylowicz,

IL-33, ST2, and ILC Pathways

Discuss this article on the JACI Journal Club blog: www.jaci-online.blogspot.com. Asthma is a chronic inflammatory disease characterized clinically by variable small airways obstruction and hyperresponsiveness and pathologically by airways inflammation and remodeling. The current cornerstone of asthma therapy is anti-inflammatory glucocorticoids. Although glucocorticoids improve clinical features of disease and airways inflammation in most patients, there is a cohort of well-defined asthma patients in whom high-dose glucocorticoid treatment is not only clinically ineffective but also potentially detrimental.1Wenzel S.E. Asthma phenotypes: the evolution from clinical to molecular approaches.Nat Med. 2012; 18: 716-725Crossref PubMed Scopus (1523) Google Scholar Improved understanding and management of glucocorticoid-resistant asthma is vitally important because these patients are very difficult to manage clinically and are at high risk of hospitalization, morbidity, and mortality. A number of mechanisms have been proposed to contribute to glucocorticoid-resistant asthma, including increased expression of nuclear factor kappa B and activating protein 1 (AP-1), increased expression of histone deacetylase, polymorphisms in IL-10, increased expression of the dominant negative isoform of the glucocorticoid receptor beta (GRβ), and vitamin D insufficiency.2Barnes P.J. Adcock I.M. Glucocorticoid resistance in inflammatory diseases.Lancet. 2009; 373: 1905-1917Abstract Full Text Full Text PDF PubMed Scopus (760) Google Scholar, 3Sutherland E.R. Goleva E. Jackson L.P. Stevens A.D. Leung D.Y. Vitamin D levels, lung function, and steroid response in adult asthma.Am J Respir Crit Care Med. 2010; 181: 699-704Crossref PubMed Scopus (304) Google Scholar, 4Gupta A. Sjoukes A. Richards D. Banya W. Hawrylowicz C. Bush A. et al.Relationship between serum vitamin D, disease severity, and airway remodeling in children with asthma.Am J Respir Crit Care Med. 2011; 184: 1342-1349Crossref PubMed Scopus (247) Google Scholar Our earlier data showed that peripheral blood CD4+ T cells from glucocorticoid-resistant as compared with glucocorticoid-sensitive asthmatic patients failed to synthesize the anti-inflammatory cytokine IL-10 in response to glucocorticoid in vitro.5Hawrylowicz C. Richards D. Loke T.K. Corrigan C. Lee T. A defect in corticosteroid-induced IL-10 production in T lymphocytes from corticosteroid-resistant asthmatic patients.J Allergy Clin Immunol. 2002; 109: 369-370Abstract Full Text Full Text PDF PubMed Scopus (105) Google Scholar The active form of vitamin D (calcitriol; 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]) when used in combination with glucocorticoid restored this IL-10 response both in vitro and ex vivo following patient ingestion of calcitriol.6Xystrakis E. Kusumakar S. Boswell S. Peek E. Urry Z. Richards D.F. et al.Reversing the defective induction of IL-10-secreting regulatory T cells in glucocorticoid-resistant asthma patients.J Clin Invest. 2006; 116: 146-155Crossref PubMed Scopus (479) Google Scholar These data, together with epidemiologic evidence linking vitamin D insufficiency/deficiency with a poor clinical response to treatment in asthma,3Sutherland E.R. Goleva E. Jackson L.P. Stevens A.D. Leung D.Y. Vitamin D levels, lung function, and steroid response in adult asthma.Am J Respir Crit Care Med. 2010; 181: 699-704Crossref PubMed Scopus (304) Google Scholar, 4Gupta A. Sjoukes A. Richards D. Banya W. Hawrylowicz C. Bush A. et al.Relationship between serum vitamin D, disease severity, and airway remodeling in children with asthma.Am J Respir Crit Care Med. 2011; 184: 1342-1349Crossref PubMed Scopus (247) Google Scholar provided the rationale for this proof-of-concept clinical trial. We characterized a group of patients with severe asthma as glucocorticoid resistant following a standardized, 2-week course of oral prednisolone (Screening) using our previously established and generally accepted criteria.6Xystrakis E. Kusumakar S. Boswell S. Peek E. Urry Z. Richards D.F. et al.Reversing the defective induction of IL-10-secreting regulatory T cells in glucocorticoid-resistant asthma patients.J Clin Invest. 2006; 116: 146-155Crossref PubMed Scopus (479) Google Scholar Following a washout period, patients were randomly assigned placebo or 0.25 μg calcitriol twice daily, according to British National Formulary guidelines, for 4 weeks with a repeat course of oral prednisolone during the final 2 weeks. We hypothesized that concomitant calcitriol therapy improves clinical glucocorticoid responsiveness in these patients. It should be noted that calcitriol, a downstream metabolite of 25-hydroxyvitaminD (25[OH]D), would not be expected to restore vitamin D sufficiency, as defined by circulating 25(OH)D: our intention was to address the short-term effects of calcitriol itself. Details of the patient recruitment and study protocol may be seen in the Methods section of this article's Online Repository at www.jacionline.org. There were no differences in patients' demographic characteristics including age, body mass index, atopic status, baseline FEV1, and inhaled glucocorticoid usage between the 2 randomized groups (see Table E1 in this article's Online Repository at www.jacionline.org). There were no serious adverse events, and all such events were self-limiting (see Table E2 in this article's Online Repository at www.jacionline.org). Differential blood leukocyte counts showed a similar increase in circulating neutrophils and reduction of eosinophils in response to both courses of prednisolone therapy in all patients, confirming compliance with this treatment (data not shown). On the basis of the primary outcome of change in lung function from the initial screening visit to the end of treatment, we saw no significant difference in % predicted FEV1 between the 2 groups (P = .82; Table I). Nevertheless, a within-group comparison showing the change in lung function during the initial screening in response to 2-week oral prednisolone (Screening) versus the response to an identical course of prednisolone plus either placebo or calcitriol (Treatment) revealed a modest but significant improvement in absolute and predicted FEV1 within the calcitriol (P = .03) but not the placebo arm (Fig 1, A). These differences were not apparent in patients randomized to receive calcitriol before the second course of prednisolone, suggesting that calcitriol alone had had no effect on lung function.Table IPrimary and secondary outcomesClinical measurementScreeningTreatmentPre-steroidsPost-steroidsPre-steroids post-treatmentPost-steroids post-treatmentFEV1 (L/s) Placebo1.82 (1.44-2.21)1.82 (1.79-2.44)1.83 (1.42-2.23)2.01 (1.61-2.41) Calcitriol1.98 (1.67-2.29)1.88 (1.52-2.23)1.96 (1.58-2.34)2.20 (1.64-2.75)FEV1 (%) Placebo59.9 (48.8-71.0)59.9 (48.3-71.3)60.6 (46.7-74.7)65.9 (55.0-76.8) Calcitriol62.5 (55.2-69.8)59.5 (49.8-69.2)61.6 (53.3-69.9)68.1 (55.4-80.7)Serum 25(OH)D (nmol/L) Placebo42.6 (26.5-58.6)44.6 (30.7-58.6)53.2 (35.4-71.0)50.8 (31.2-70.5) Calcitriol32.5 (21.5-43.5)34.3 (21.5-43.5)37.1 (15.9-58.4)34.4 (19.6-49.2)Note: Data shown as mean ± 95% CIs. Open table in a new tab Note: Data shown as mean ± 95% CIs. In the placebo cohort, 4 of the 11 patients showed a more than 10% improvement in their lung function post-prednisolone in the treatment phase than in the screening phase. Retrospective analysis of serum concentrations of 25(OH)D in these patients showed that 6 patients exhibited elevation of their baseline serum 25(OH)D concentrations from start to final visit of study (Fig 1, B). A trend for a positive correlation between baseline serum 25(OH)D concentrations and change in predicted lung function following prednisolone (r = 0.56, P = .08; Fig 1, C) was observed. Despite the very low numbers, a greater improvement in FEV1 following prednisolone in those with relatively high (>50 nmol/L; n = 6) as compared with low (<50 nmol/L; n = 5) serum concentrations of 25(OH)D was seen (P = .03; Fig 1, D). This study represents the first demonstration to our knowledge that the clinical responsiveness of asthmatic patients to glucocorticoid therapy is subject to manipulation in the short term. Our data show that treatment with a short course of 1,25(OH)2D3 (calcitriol) may modestly improve the clinical glucocorticoid responsiveness in asthma, even in patients classified as clinically glucocorticoid resistant. This study was not designed to correct or take account of the patients' vitamin D status. Nevertheless, all but 1 of the patients were vitamin D insufficient (<75 nmol/L) and 16 of our patients were deficient ( 20% diurnal peak expiratory flow rate variability) documented within the previous 5 years. Individuals were excluded if they suffered from past or present disease, which, as judged by the investigator, might affect the study outcome (other than asthma, rhinitis, or eczema); if serum-corrected calcium was more than 2.65 mol/L; if they were a current cigarette smoker or ex-smoker of less than 5 years with a more than 5 pack-year history; if they were pregnant or lactating females or at risk of pregnancy; if they had a history of a respiratory tract infection and/or exacerbation of asthma within 4 weeks of the screening visit requiring oral glucocorticoid therapy; if they had participated in a study involving an investigational medicinal product in the previous 3 months or had made a blood donation within the last year; if they were currently receiving, or had received, allergen immunotherapy or treatment with lithium carbonate or calcium supplements; or if they were unable to understand or comply with the research protocol. Patients were asked, and agreed not to take any vitamin supplements for the duration of the study. Patients remained on their regular maintenance medication for the duration of the study, including the 4-week washout period. On the day of screening, 8 (34.7%) patients showed more than 20% peak flow variability and 15 (65.3%) showed reversibility to a bronchodilator response. However, all 8 patients who were enrolled on the basis of peak flow variability had shown significant bronchodilator response within 5 years prior to enrolling into the study. All patients who went through the screening period (ie, 2 weeks of oral corticosteroids) had confirmed bronchodilator reversibility. Glucocorticoid-resistant asthma was defined as less than 10% improvement in baseline FEV1 following a 14-day course of oral prednisolone (Wockhardt UK Ltd, Wrexham, United Kingdom; 40 mg/1.73 m2/d) in eligible patients. Routine spirometry was measured before and after the course of prednisolone using a PC-based spirometer and software (MIR Medical International Research, Rome, Italy/WinspiroPRO). In addition, differential full blood cell counts were performed before and after the course of prednisolone using a LH750 hematology analyzer (Beckman Coulter, Brea, Calif). Fifty patients were screened for eligibility between April 2009 and September 2012. Twenty-five patients were excluded before or during the screening period: 7 patients did not meet inclusion criteria, 3 declined to participate, 3 were noncompliant with the protocol, and 12 were steroid sensitive (>10% improvement in FEV1 compared with baseline). One patient was lost to follow-up after completion of the screening visits. Twenty-four patients were randomized: 11 were allocated to placebo, 13 to intervention. One patient in the treatment group withdrew because of an adverse event, thought to possibly be related to the study drug (Fig E1; clinical flow diagram), making it 12 patients to complete the treatment group in that arm. There were no serious adverse events, and all events were self-limiting (Table E1). The study outline is summarized in Fig E1. Participants who met the eligibility criteria for glucocorticoid-resistant asthma returned following a 4-week washout period and were randomly allocated to commence treatment with either calcitriol 0.25 μg soft capsules (Rocaltrol; Roche Pharmaceuticals, Welwyn Garden City, United Kingdom) or organoleptically identical lactose placebo generated in-house (Pharmacy Production Unit, St Thomas' Hospital NHS Trust, London, United Kingdom) twice daily. Patients were randomized in a 1:1 ratio using a computerized random plan generated by a physician not involved in the trial. Patients and trial investigators were blinded to treatment allocation. Following 2 weeks of calcitriol or placebo treatment, patients were given a second course of oral prednisolone identical to the first while calcitriol or placebo was continued. Spirometry was performed at the beginning and end of this second course of oral prednisolone as before. Serum concentrations of calcium, corrected calcium, albumin, total protein, phosphate, sodium, potassium, urea, creatinine, and 25(OH)D were analyzed. Concentrations of 25(OH)D2 and 25(OH)D3 were determined by isotope-dilution liquid chromatography–tandem mass spectrometry and summed to give values for total 25(OH)D. Sensitivity for this assay was 10 nmol/L. Full blood cell counts were performed as described above. Albumin, phosphate, and total serum calcium concentrations were determined using an Architect ci8200 analyzer (Abbott Diagnostics, Chicago, Ill). Calcium concentration was corrected for serum albumin concentration using the formula: corrected calcium (mmol/L) = total calcium (mmol/L) + 0.02 × (40 – albumin [g/L]). Power calculations predicted that the study of 40 glucocorticoid-resistant participants would enable detection of an improvement in change in FEV1 from 0.4% to 10% with 80% power, tested at the 2-sided 5% significance level. Because of difficulties with patient recruitment, however, the decision was made to terminate the study after 24 patients completed. The primary outcome measure was change in FEV1 from screening to the final visit. Secondary outcomes measured included asthma control questionnaire and serum 25(OH)D measurements. There was no difference observed in the asthma control questionnaire scores between the calcitriol and placebo treatment groups. Additional analysis of glucocorticoid response was performed within (screening vs treatment phases) and between groups (calcitriol vs placebo), expressed as absolute values and percentage change. Study subjects were asked to report any adverse events from the day of commencement of the first course of oral prednisolone until 4 weeks after the second course by telephone or e-mail or at study visits. The differences in % predicted FEV1 at 28 days postrandomization between treatment groups was assessed using a linear regression model adjusted for screening values of % predicted FEV1 value and vitamin D status. The analysis was performed on the complete case population, and statistical significance was assessed at the 5% level. For subsequent subanalyses, data were assessed for Gaussian distribution and equality of variance. Then, for normally distributed data, assessment was done by either an unpaired or a paired (where appropriate) Student t test and for non-normally distributed data, Wilcoxon matched-pairs signed test (paired data) and Mann-Whitney U test (unpaired). Correlations were nonnormally distributed and were assessed by Spearman rank correlation test. Normally distributed data were presented as the mean ± 95% CIs, and nonnormally distributed data were shown as median ± interquartile range.Table E1Patients' characteristicsCharacteristicPlaceboCalcitriolAge (y)53.5 (47.8-59.1)50.3 (39.1-61.6)Ethnic origin Caucasian98 African23 Asian01Sex Male77 Female46Atopic109BMI29.1 (25.0-33.2)27.4 (25.5-29.2)Inhaled corticosteroid dose1236 (830-1643)1267 (849-1684)Feno19.9 (15.7-24.1)38.4 (20.7-56.0)n = 11n = 12Note: Data are presented as the mean and 95% CI. Atopy was defined by skin prick testing. The dose of inhaled corticosteroids was calculated according to the British Thoracic Society - Scottish Intercollegiate Guidelines Network (BTS-SIGN) Guideline on the management of asthma (Table 8b: Equivalent doses of inhaled steroids relative to BDP and current licensed age indications). Patients were on beclomethasone 1600 μg/d, budenoside 1600 μg/d, or fluticasone 800 μg/d.BDP, Beclomethasone dipropionate; BMI, body mass index; Feno, fractional exhaled nitric oxide; 25(OH)D, 25-hydroxyvitamin D. Open table in a new tab Table E2Side effects documented throughout the trialAdverse eventStudy phaseStudy drugRelated to study drugMild indigestionScreeningPrednisoloneYesNauseaScreeningPrednisolonePossibleIncreased hungerScreeningPrednisoloneYesCoryzal symptomsTreatmentPlaceboNoDiarrheaTreatmentPlaceboNoCoryzal symptomsTreatmentCalcitriolNoCoryzal symptomsTreatmentCalcitriolNoCoryzal symptomsTreatmentCalcitriolNoConstipation, back painTreatmentCalcitriolPossibleBang to headTreatmentCalcitriolNoNote: All effects were nonsevere and resolved spontaneously. Open table in a new tab Note: Data are presented as the mean and 95% CI. Atopy was defined by skin prick testing. The dose of inhaled corticosteroids was calculated according to the British Thoracic Society - Scottish Intercollegiate Guidelines Network (BTS-SIGN) Guideline on the management of asthma (Table 8b: Equivalent doses of inhaled steroids relative to BDP and current licensed age indications). Patients were on beclomethasone 1600 μg/d, budenoside 1600 μg/d, or fluticasone 800 μg/d. BDP, Beclomethasone dipropionate; BMI, body mass index; Feno, fractional exhaled nitric oxide; 25(OH)D, 25-hydroxyvitamin D. Note: All effects were nonsevere and resolved spontaneously.