1. 12 months before treatment 12 months after treatment
Evaluating the selection of patients with asthma treated with omalizumab: A retrospective, descriptive study J Hutchison1, C Souter1,2, A Kurdi NHS Lothian Pharmacy Service 2 University of Strathclyde
BACKGROUND AND AIM
Omalizumab is a monoclonal antibody used to treat severe asthma. The product licence and clinical guidance from the Scottish Medicines Consortium (SMC) and National Institute for Healthcare and Excellence(NICE) specify criteria that should be met when selecting patients for treatment with omalizumab. Literature reports variation in patients fulfilling all criteria.
This study aimed to evaluate adherence to treatment eligibility criteria and profile the characteristics of patients initiated on omalizumab for asthma.
METHOD
Retrospective, descriptive, single centre study performed at the Western General Hospital (WGH), Edinburgh.
Twenty patients were initiated on omalizumab for asthma between October 2007 and July 2017.
Data from patients’ primary and secondary care electronic notes and prescribing records was used to profile patient characteristics and evaluate clinical outcomes (Figure 1).
Two sets of eligibility criteria were developed to reflect the change in evidence based guidance: the product licence and SMC guidance informed the criteria for patients commenced before April 2013 and the product licence and NICE guidance were used for patients after April 2013.
12 months before treatment
12 months after treatment
Index date
Gender; age; ethnicity; IgE; weight; smoking status; % predicted FEV1; omalizumab dose; daily OCS maintenance dose
Prescription refill; number of SABA inhalers dispensed; number of emergency attendances or hospital admissions; number of acute steroid prescriptions
Daily OCS dose
ELIGBILITY CRITERIA
1. Patient is 12 years or older
2. Diagnosis of severe, allergic persistent asthma
3. Positive skin test or IgE reactivity to perennial allergen
4. FEV1 less than 80% predicted
5. Frequent day time symptoms or night time awakening
6. Multiple exacerbations despite high dose inhaled corticosteroids (ICS) and long-acting beta-2-agonist (LABA)
7. Baseline IgE and weight within limits of product literature for dose selection
8. Chronic systemic steroids
9. All other asthma treatments failed (defined as a full trial of high dose ICS, LABA, SABA and fourth drug e.g. Leukotriene receptor antagonist (LRTA) or theophylline in line with SIGN 101 step 41)
10. Optimised therapy (defined as a full trial of, and if documented compliance with, high dose ICS, LABA, LRTA, theophylline, oral corticosteroids and smoking cessation where applicable)
11. Continuous or frequent treatment with oral corticosteroids (frequent treatment defined as four or more courses in the previous year)
Figure1: Timeline of data collection
IgE-immunoglobulin E; % FEV1 predicted; % of predicted forced expiratory volume in one second; OCS-oral corticosteroid; SABA-short-acting beta-2-agonist
Table 1: Eligibility criteria
Criteria 1-7 were developed from the manufacturer product licence2; 8 and 9 from the SMC3; 10 and 11 from NICE4.
RESULTS
Table 2: Omalizumab treatment outcomes
CLINICAL OUTCOME
TOTAL PATIENTS
(n=20)
Number of patients on maintenance OCS
Prior to omalizumab*
After omalizumab#
17 (85%)
9 (45%)
Mean OCS daily dose
Mean change
4.9mg (4.9)
2.9mg (6.4)
-2.0mg (3.8)
Mean number of acute OCS prescriptions (asthma exacerbations) in 12 months
Prior to omalizumab**
After omalizumab##
3.5 (2.8)
1.7 (2.0)
-1.8 (3.2)
Mean number of hospital admissions or emergency attendances in 12 months
0.5 (0.8)
0.2 (0.5)
-0.3 (0.8)
Figure 2: Adherence to eligibility criteria for patients commenced on omalizumab prior to April 2013 (n=6)
Figure 4: Adherence to maintenance ICS expressed as dispensed daily dose/defined daily dose in the 12 months before and after commencing omalizumab
Data presented as mean (SD) or n (%). *At the point of starting omalizumab (index date). **Over the 12 month period prior to index date. #at 12 months after index or when treatment stopped if within this period. ##over the 12 month period after index date or treatment cessation if within this period.
Figure 3: Adherence to eligibility criteria for patients commenced on omalizumab after April 2013 (n=14)
DISCUSSION AND CONCLUSIONS
Results indicated poor adherence to prescribing guidelines when selecting patients for treatment with omalizumab.
Patient adherence to ICS prior to omalizumab use was also suboptimal.
Positive clinical outcomes in oral corticosteroid use and exacerbation rates have been observed following treatment with omalizumab, it is appropriate to question whether similar positive outcomes could have been achieved if patients’ adherence to ICS had been optimised.
Further work should focus on how to improve patient selection for omalizumab treatment and ensuring appropriate adherence to standard therapy prior to commencing monoclonal antibodies.
Scottish Intercollegiate Guidelines Network (SIGN). SIGN 141: British guideline on the management of asthma. Scottish Intercollegiate Guideline Network Accessed 16 Jul 2018
Novartis Pharmaceuticals UK Ltd. Xolair 150mg solution for injection. Novartis Pharmaceuticals UK Ltd. Accessed 04 Jan 2018.
Scottish Medicines Consortium. Detailed advice document: Omalizumab 150mg powder and solvent for injection (Xolair®) No. (259/06). Scottish Medicines Consortium Accessed 19 Jun 2018.
The National Institute for Health and Care Excellence. Omalizumab for treating severe persistent allergic asthma. Technology appraisal guidance TA278. The National Institute for Health Care and excellence Accessed 28 Jun 2018.