|A systematic review of the clinical effectiveness and cost-effectiveness of Pharmalgen for the treatment of bee and wasp venom allergy
|Hockenhull J, Elremeli M, Cherry MG, Mahon J, Lai M, Darroch J, Oyee J, Boland A, Dickson R, Dundar Y, Boyle R
This review found that no confident conclusions could be made on the effectiveness of Pharmalgen as immunotherapy for people with a history of type I systemic allergic reaction to bee or wasp venom. The data were limited and diverse, and study quality was poor, so the authors' conclusions are appropriate.
To assess the effectiveness of Pharmalgen, as an immunotherapy, for people with a history of type I immunoglobulin E-mediated systemic allergic reaction to bee or wasp venom.
MEDLINE, EMBASE and The Cochrane Library were searched up to February 2011. Search strategies were presented.
All comparative studies of Pharmalgen were eligible if the participants had a history of type I immunoglobulin E-mediated systemic allergic reaction to bee or wasp venom, or both. The outcomes had to be: systemic and local adverse reactions to treatment and to subsequent stings, anxiety over future allergic reactions, or quality of life.
In the included studies, a range of different approaches to Pharmalgen therapy were used, with the comparator generally being another form of Pharmalgen therapy, or Aquagen or Alutard therapy. The average age of participants ranged from 35 to 49 years, and the percentage of men ranged from 57 to 88. Four studies were co-authored by the manufacturer, and three studies used venom provided by the medication manufacturer.
Two reviewers selected the studies, with disagreements resolved by discussion.
Assessment of study quality
Study quality was assessed for randomisation, baseline comparability of groups, eligibility criteria and co-interventions, blinding, withdrawals and outcome reporting. One reviewer assessed quality, and this was checked by a second reviewer.
Data were extracted on the numbers of participants experiencing systemic reactions to re-stings, large local reactions and adverse reactions. One reviewer extracted these data, which were checked by a second reviewer.
Methods of synthesis
A narrative synthesis was performed, with data presented in tables. A meta-analysis and mixed-treatment comparison were planned, but were not deemed appropriate.
Results of the review
Nine studies were eligible, with over 400 participants (range 30 to 65); four were randomised controlled trials. Follow-up times ranged from four days to over three years. Study quality was judged to be poor, particularly for reporting randomisation, lack of blinding, and imbalance in the number of drop-outs between arms.
In eight studies, the incidence of systemic reactions to re-sting ranged from zero to 36.4%. Two studies compared the incidence across study arms and found no difference in incidence between arms. Two studies compared large local reactions between arms: one found no difference in incidence, the other found a higher incidence with subcutaneous use (88.9%) than with sublingual use (50%).
Five studies reported systemic reactions during the treatment period, with rates ranging from zero to 38.1%. Three of these found no difference between study arms; the results for the other two were unclear. Four studies reported large local reactions during the treatment period. The rates with subcutaneous treatment ranged from 6.7% to 60%. There were no reported reactions with sublingual treatment. Two studies compared rates between study arms and found no differences.
None of the studies reported quality of life or anxiety data.
A similar review was conducted to assess the cost-effectiveness of Pharmalgen and no published evidence was found. A model, based on survey data, found that the incremental cost-effectiveness ratio of Pharmalgen, over alternative therapies, was not less than £700,000 per quality-adjusted life-year, except in groups at a high risk of sting, where it was approximately £24,000 per quality-adjusted life-year.
The use of Pharmalgen immunotherapy appeared to be based on evidence of limited and poor quality. Conclusions on its effectiveness in reducing systemic reactions could not be made with any confidence.
This review addressed a suitable question, with appropriate inclusion criteria. A suitable search was conducted, but it was unclear whether unpublished material was sought, so some studies may have been missed. Appropriate action was taken to reduce reviewer error and bias. Study quality was assessed and studies were judged to be of poor quality. A narrative review was performed, which was appropriate given the limited and diverse nature of the data. The authors noted that all studies were small, with limited data, and the studies varied considerably in how the treatment was administered and their duration. This made comparisons across studies difficult.
For all these reasons, the authors' statement that no reliable conclusions could be drawn from this review was appropriate.
Implications of the review for practice and research
Practice: The authors noted that sting reactions, after Pharmalgen, were low and adverse reactions to it were minor and easily treatable.
Research: The authors suggested that research should focus on identifying the groups of patients who were most likely to benefit from treatment, and that data on the use of venom immunotherapy should be routinely collected.
Funded by the NIHR Health Technology Assessment programme, UK.
Hockenhull J, Elremeli M, Cherry MG, Mahon J, Lai M, Darroch J, Oyee J, Boland A, Dickson R, Dundar Y, Boyle R. A systematic review of the clinical effectiveness and cost-effectiveness of Pharmalgen for the treatment of bee and wasp venom allergy. Health Technology Assessment 2012; 16(12): 1-110
Subject indexing assigned by NLM
Adolescent; Adult; Aged; Allergens /drug effects; Anaphylaxis /drug therapy; Antigens, Dermatophagoides /administration & Bee Venoms /adverse effects; Cost-Benefit Analysis; Female; Great Britain; Humans; Male; Middle Aged; Treatment Outcome; Wasp Venoms /adverse effects; Young Adult; dosage /economics /therapeutic use
Date bibliographic record published
Date abstract record published
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.