Sputum Induction Method to Optimize Respiratory Patient Clinical Trials Authors: Dr

LIFE SCIENCE I TECHNICAL BULLETIN APRIL 2016

SPUTUM INDUCTION METHOD TO OPTIMIZE RESPIRATORY PATIENT CLINICAL TRIALS AUTHORS: DR. ROBERT LINS – SGS SENIOR CLINICAL ADVISER - CLINICAL RESEARCH

Sputum induction has long been established as the best available non-invasive method to evaluate airway inflammation. It was first used for diagnosing Pneumocystis carinii pneumonia (PCP) in patients infected with human immunodeficiency virus (HIV)1. By administering 5% hypertonic saline through an ultrasonic nebulizer for 10 or 20 minutes, sputum could be induced in the majority of patients with acquired immunodeficiency syndrome (AIDS). The method was later adapted for examining the inflammatory response in asthma2. In recent years, sputum induction by hypertonic saline and its subsequent processing has been refined as a noninvasive research tool and, increasingly, as a clinical tool to provide important information about inflammatory events in the lower airways.

Induced sputum has been used for on a large scale in clinical studies. Also, cancer, respiratory infections and in studying various illnesses, including from a safety perspective, the procedure diagnosis of PCP in patients infected asthma, chronic obstructive pulmonary still entails some morbidity. with HIV. In developing countries with disease (COPD), tuberculosis, PCP, cystic a high prevalence of pulmonary tuber- fibrosis, lung cancer and chronic cough. With sputum induction, samples can be culosis, sputum induction can increase Asthma is a heterogeneous disorder obtained from the lower airways with the diagnostic yield, resulting in better characterized by chronic airway inflam- minimal discomfort to the patient, and is categorization of patients for treatment mation, hyperresponsiveness and remod- thought to provide a better representa- purposes. The method can also increase eling. Being the hallmark of asthma, tive sample of several proximal airways. the case detection rate of smear nega- airway inflammation has become the The technique also allows the distal parts tive pulmonary tuberculosis especially in most important target for therapeutic to be sampled with prolonged induction, areas where facilities for more invasive agents. as evident from increased numbers of and expensive techniques are not avail- macrophages from the alveolar com- able or viable. COMPARISONS AND partment. The technique can be used ADVANTAGES OF THE for the evaluation of inflammatory cells The reproducibility of the method has and eosinophils, of biomarkers such as: been repeatedly questioned however, TECHNIQUE tumor necrosis factor (TNF), interleukin and the preparation of the obtained Sputum induction by inhalation of hyper- (IL), macrophage inflammatory protein-1 sputum samples for bio-analysis is labor tonic saline is a simple, cost effective (MIP-1α), monocyte chemotactic factor-1 intensive and demanding for technicians 3 and safe procedure, and has several (MCP-1), metalloproteinases (MMP), trained in the procedure . There have advantages over other techniques. It has transforming growth factor-β (TGF-β), been only a few methodological studies a higher yield in comparison to sponta- platelet derived growth factor (PDGF) that have examined the influence of vari- neous sputum, bronchoalveolar lavage and also for studying local immunoge- ous technical factors on the repeatability (BAL), bronchial washing and gastric nicity against inhaled drugs. It is widely of sputum induction and collection, and lavage. Bronchoscopy allows sampling used in asthma and COPD but also as as such, there is no ‘gold standard’ prac- of the cells, biomarkers and pharmacoki- a complementary tool to BAL both in tice for this technique. netic data by means of BAL and enables the research and clinical monitoring of the biopsy of mucosal tissue. Although patients with interstitial lung disease. relatively safe, BAL is an invasive procedure and more expensive than sputum The cells, recovered from spontaneous induction, and is not easily applicable coughing can be used to study lung

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TECHNICAL ASPECTS example bronchodilator reversibility. To is feasible and reproducible for the study assess for excessive bronchoconstriction of biomarkers in respiratory diseases. The technique of sputum induction con- during sputum induction, measurements The positive outcome is entirely due to sists of inhaling an aerosol of hypertonic of FEV1 will be taken at approximately the strict follow-up of procedures and saline with increasing concentrations of seven minute intervals, or sooner if the repeated operational and laboratory 3, 4, and 5% over different time-periods. subject becomes symptomatic. Pulse ox- staff training. Patients with a history Ultrasonic nebulizers are recommended imetry should be monitored in conjunc- of asthma and smoking are of course for inducing sputum since other nebuliz- tion with FEV1 at the same seven minute better candidates for this procedure, but ers do not usually have sufficient saline intervals during the induction. the same strict procedures and train- aerosol output. Spirometry is necessary ing are necessary. There were no other to assess the baseline airway caliber It is recommended that sputum be pro- parameters that could predict adequate and avoid excessive bronchoconstriction cessed as soon as possible and within sampling. during saline inhalation. Spirometers are two hours, in order to ensure optimum preferable to peak flow meters because cell counting and staining. The sample The application of this procedure has of the greater sensitivity of measur- preparation can take up to two hours per also been studied successfully by others ing the dynamic lung volume after one sample and requires trained technicians in infants with different chronic airways second of forced expiration (FEV ) in 1 for both the induction procedure and the diseases4,5,6. Moreover sputum induc- detecting induced bronchoconstriction. sample handling/cell counting. tion can also be safely and successfully Sputum induction requires a high degree performed in patients with severe, dif- of cooperation from the patient, and only CASE STUDY ficult- to-control asthma if a standardized an experienced technician under the protocol is used7. supervision of an experienced physician SGS undertook a study of the character- 3 should conduct the procedure . istics of healthy volunteers and asthma CONCLUSION patients in sputum induction during The technique requires pretreatment proof of concept studies to assess its The identification of biomarkers that al- with salbutamol, preferably 4 puffs of viability as a method. Healthy volunteers low monitoring and optimization of drug 100 μg via spacer or nebulizer and then and asthma patients were recruited in a development in lung disease therapy is post-bronchodilator spirometry, which phase 1 unit designed for participants un- one of the most ambitious goals in re- serves as the pre-induction FEV1 baseline dertaking early phase respiratory studies, spiratory medicine. The induced sputum for safety monitoring. This pre-induction where sputum induction in the baseline technique allows sampling of the airways FEV1 should be greater than 65%. screening was included. Sputum induc- in a noninvasive manner and as such of- tion was performed according to the fers a unique opportunity for the identifi- Sputum will be induced for approximate- technique described above and basic cation of biomarkers for potential clinical ly 21 minutes divided into three, seven demographics and spirometer results use in respiratory medicine. It is hoped minute sessions of nebulization, followed were collected. In some cases a second that, in the future, induced sputum will by a three step cleansing procedure and induction was performed on participants provide clinicians with useful markers a focused cough attempt. Throughout the after 2-30 days. that can be used to perform more accu- process, regular spirometry is required rate and, ideally, more rapid development for safety monitoring. In recognition of The outcome parameter was an of drugs and for determination of disease intra-subject variability between vis- adequate sputum sample, which was phenotypes in many lung diseases, lead- its, guidelines have been provided for defined as a weight of more than 0.4 ing to precision medicine. investigators to consider where subjects g and visible plugs. Of the 150 eligible whose post-bronchodilator FEV1 may subjects, 102 volunteers (78 healthy The hope is that the induced sputum be below 65% at visits where sputum non-smokers, 10 healthy smokers and technique will provide a simple and induction is to be performed. If the 14 asthma patients) underwent sputum cost-effective tool for assessing the pre-induction post-bronchodilator FEV1 is induction. The mean age was 40.3 ± anti-inflammatory potential of new treat- greater than 60%, then sputum induction 10.9 years and 84 % of the participants ments, an approach that was precluded may be performed starting with 3% and were male. Adequate sputum samples by previous techniques such as bronchial increasing to 4% and then 5% hyper- were obtained in 68 (67 %) subjects, 29 biopsy and bronchoalveolar lavage. tonic saline, if their FEV1 remains at least % in healthy, 75 % in smokers and 74 90% of the pre-induction baseline before % in asthmatic patients. There were no increasing to 4% and then 5% saline. differences in age, sex, BMI, vital signs

With lower FEV1 values a more cautious between the groups with adequate and approach is followed, starting with a non-adequate samples. Reproducibility in lower concentration and a more gradual 51 subjects tested twice was 86 % (intra increase of the dose. subject difference in sputum weight -2.2 mg 95%CI 27.7). There were no major

No medication holds are required for decreases in FEV1 and the procedure sputum induction unless the procedure was well tolerated. It was concluded is performed after other procedures that the use of sputum induction in that do require medication holds, for healthy volunteers and asthma patients LIFE SCIENCE I TECHNICAL BULLETIN 3

REFERENCES 1. Pitchenik AE, Ganjei P, Torres A, Evans DA, Rubin E, Baier H. Sputum examination for the diagnosis of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. Am Rev Respir Dis 1986;133:226-229. 2. Pin I, Gibson PG, Kolendowicz R, et al. Use of induced sputum cell counts to investigate airway inflammation in asthma. Thorax 1992;47:25-29. 3. Paggiaro PL, Chanez P, Holz O, Ind PW, Djukanovic R, Maestrelli P, Sterk PJ. Sputum induction. Eur Respir J 2002;20:Suppl.37,3s–8s. 4. Jones PD, Hankin R, Simpson J, Gibson PG, and Henry RL. The Tolerability, Safety, and Success of Sputum Induction and Combined Hypertonic Saline Challenge in Children. Am J Resp & Crit Care Med 2001;164:1146-1149 5. Grant LR, Hammitt LL, Murdoch DR, O’Brien KL, J. Anthony Scott JA. Procedures for Collection of Induced Sputum Specimens From Children. Clin Infect Dis 2012;54(suppl 2):S140-S145. 6. Jochmann A, Artusio L, Robson K, Nagakumar P, Collins N, Fleming L, Bush A, Saglani S. Infection and inflammation in induced sputum from preschool children with chronic airways diseases. Pediatr Pulmonol 2015 Dec 17. doi: 10.1002/ppul.23366. [Epub ahead of print] 7. ten Brinke A, de Lange C, Zwinderman AH, Rabe KF, Sterk PJ, Bel EH. Sputum Induction in Severe Asthma by a Standardized Protocol Predictors of Excessive Bronchoconstriction. Am J Resp & Crit Care Med 2001;164:749-753.

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