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Background: Each year in the UK, there are between two and nine deaths from anaphylaxis caused by bee and wasp venom. Anaphylactic reactions can occur rapidly following a sting and can progress to a life-threatening condition within minutes. To avoid further reactions in people with a history of anaphylaxis to bee and wasp venom, the use of desensitisation, through a process known as venom immunotherapy (VIT), has been investigated and is in use in the UK. VIT consists of subcutaneous injections of increasing amounts of purified bee and/or wasp venom extract. Pharmalgen® products (ALK Abelló) have had UK marketing authorisation for VIT (as well as diagnosis) of allergy to bee venom (using Pharmalgen Bee Venom) and wasp venom (using Pharmalgen Wasp Venom) since March 1995. Objective: This review assessed the clinical effectiveness and cost-effectiveness of Pharmalgen in providing immunotherapy to individuals with a history of type 1 [immunoglobulin E (IgE)-mediated] systemic allergic reaction to bee and wasp venom. Data sources: A comprehensive search strategy using a combination of index terms (e.g. Pharmalgen) and free-text words (e.g. allerg$) was developed and used to interrogate the following electronic databases: EMBASE, MEDLINE, The Cochrane Library. Review methods: Papers were included if they studied venom immunotherapy using Pharmalgen (PhVIT) in patients who had previously experienced a systemic reaction to a bee and/or a wasp sting. Comparators were any alternative treatment options available in the NHS without VIT. Included outcomes were systemic reactions, local reactions, mortality, anxiety related to the possibility of future allergic reactions, health-related quality of life (QoL) and adverse reactions (ARs) to treatment. Cost-effectiveness outcomes included cost per quality-adjusted life-years (QALYs) gained. Because of the small number of published randomised controlled trials (RCTs), no meta-analyses were conducted. A de novo economic model was developed to assess the cost-effectiveness of PhVIT plus high-dose antihistamine (HDA) plus adrenaline auto-injector (AAI) plus avoidance advice in relation to two comparators. Results: A total of 1065 citations were identified, of which 266 full-text papers were obtained. No studies were identified that compared PhVIT with any of the outlined comparators. When these criteria were widened to include different protocols and types of PhVIT administration, four RCTs and five quasi-experimental studies were identified for inclusion. The quality of included studies was poor, and none was conducted in the UK. Eight studies reported re-sting data (systemic reactions ranged from 0.0% to 36.4%) and ARs (systemic reactions ranged from 0.0% to 38.1% and none was fatal). No included studies reported quality of life. No published economic evidence relevant to the decision problem was identified. The manufacturer of PhVIT did not submit any clinical effectiveness or cost-effectiveness evidence to the National Institute for Health and Clinical Excellence in support of PhVIT. The results of the Assessment Group’s (AG) base-case analysis show that the comparison of PhVIT + HDA + AAI versus AAI + HDA yields an incremental cost-effectiveness ratio (ICER) of £18,065,527 per QALY gained; PhVIT + HDA + AAI versus avoidance advice only yields an ICER of £7,627,835 per QALY gained. The results of the sensitivity analyses and scenario analyses showed that the results of the base-case economic evaluation were robust for every plausible change in parameter made. The results of the ‘High Risk of Sting Patients’ subgroup analysis show that PhVIT + HDA + AAI dominates both AAI + HDA and avoidance advice only (i.e. is less expensive and more effective). The ‘VIT Anxiety QoL Improvement’ subgroup analysis shows that PhVIT + HDA + AAI versus HDA + AAI has an ICER of £23,868 per QALY gained, and PhVIT + HDA + AAI versus avoidance advice only yields an ICER of £25,661 per QALY gained. Limitations: This review is limited to the use of Pharmalgen in the treatment of hymenoptera venom allergy and therefore does not assess the effectiveness of VIT in general. Conclusions: The current use of PhVIT in clinical practice in the NHS appears to be based on limited and poor-quality clinical effectiveness research. Available evidence indicates that sting reactions following the use of PhVIT are low and that the ARs related to treatment are minor and easily treatable. The results of the AG’s de novo economic evaluation demonstrate that PhVIT + AAI + HDA compared with AAI + HDA and with avoidance advice only yields ICERs in the range of £8–20M per QALY gained. Two subgroups (‘High Risk of Sting Patients’ and ‘VIT Anxiety QoL Improvement’) were considered in the economic evaluation and the AG concludes that the use of PhVIT + AAI + HDA may be cost-effective in both groups. Future research should focus on clearly identifying groups of patients most likely to benefit from treatment and ensure that clinical practice is focussed on these groups. Furthermore, given the paucity of UK data in this area it would be informative if data could be collected routinely when VIT is administered in the NHS (e.g. rates of systemic adverse reactions to VIT, rates of systemic reactions to bee/wasp stings). Funding: The National Institute for Health Research Health Technology Assessment programme.

Background: Atrial fibrillation (AF) is a tachyarrhythmia characterised by unco-ordinated atrial activation with consequent deterioration of impairment of atrial function and a rapid, irregular heartbeat. The annual incidence rate of paroxysmal AF (PAF) has been estimated at 1.0 per 1000 person-years (95% confidence interval 0.9 to 1.1), and reported prevalence rates show wide variations depending on age and country. Conventional treatment strategies for PAF focus on the suppression of paroxysms of AF and return to normal sinus rhythm. Objectives: To summarise the results of the rapid reviews of the clinical effectiveness and cost-effectiveness literature describing the pill-in-the-pocket (PiP) approach for the treatment of patients with PAF; and to develop an economic model to assess the cost-effectiveness of PiP compared with in-hospital treatment (IHT) or continuous antiarrhythmic drugs (AADs) for the treatment of patients with PAF. Data sources: Ovid MEDLINE and Ovid OLDMEDLINE 1950 to present with Daily Update were searched. The following electronic databases were searched for ongoing trials: Health Services Research Projects in Progress, ClinicalTrials.gov, metaRegister of Current Controlled Trials, BioMed Central, World Health Organization International Clinical Trials Registry Platform, ClinicalStudyResults.org and the National Library of Medicine Gateway. Review methods: Inclusion criteria, which included patients suffering from PAF, were independently applied to all identified references by two reviewers (JH and CMS). Electronic searches were conducted to identify clinical effectiveness and cost-effectiveness evidence describing the use of a PiP strategy for the treatment of PAF, published since the release of the Royal College of Physicians’ national guidelines on AF in June 2006. A Markov model was constructed to examine differences between three PAF strategies (PiP, AAD and IHT) in terms of cost per quality-adjusted life-year (QALY). A Markov model structure was chosen because it is assumed that PAF is a condition that causes patients to move between a limited number of relevant health states during their lives. Results: The search strategies for clinical studies identified 201 randomised controlled trials (RCTs). Of the 201 RCTs identified, 12 were deemed to be relevant to the decision problem as they included drugs used to treat PAF; summary data were abstracted from these studies in order to inform the development of the economic model only. The model results indicate that the PiP strategy is slightly less effective than the other two strategies, but also less costly (incremental cost-effectiveness ratio of £45,916 per QALY when compared to AAD, and £12,424 per QALY when compared to IHT). The one-way sensitivity analyses performed do not show substantial changes in relative cost-effectiveness except in relation to the age of patients, where PiP dominates AAD in men over 65 years and in women over 70 years. At a threshold of £25,000 per QALY, IHT has the maximum probability of being cost-effective at this threshold. For threshold values between £0 and £9266 per QALY, PiP is the option exhibiting the maximum probability of being cost-effective. The AAD strategy has a very poor probability of being cost-effective under any threshold. However, none of the strategies considered has more than a 40% probability of being cost-effective at a threshold of £25,000 per QALY at any threshold level. This demonstrates the uncertainty around the parameters and its effect on the decision to choose any one strategy over the others. Limitations: Most of the data used to populate the model have been taken from studies with populations that do not match the patient population specified in the decision problem. Populating the model in this way was unavoidable as there was a paucity of published clinical effectiveness and cost-effectiveness data describing a PiP strategy for this highly specific group of patients. Conclusions: Overall, a PiP strategy seems to be slightly less effective (i.e. fewer QALYs gained) than AAD and IHT, but is associated with cost savings. A PiP strategy seems to be more efficacious and cost-effective than an AAD strategy in men over 65 years and women over 70 years, but this is principally due to a very slight difference in QALY gained by the PiP strategy. A change in clinical practice that includes the introduction of PiP may save costs, but also involves a reduction in clinical effectiveness compared to existing approaches used to treat patients with PAF. Uncertainty in the available clinical data means there was insufficient evidence to support a recommendation for the use of PiP strategy in patients with PAF. Further research should identify outcomes of interest such as adverse events and recurrent AF episodes in an RCT setting because the only clinical study addressing these issues, even partially, is not an RCT but a descriptive analysis. Patient preferences also need to be considered in any future research designs.