Chronic anal fissure: botulinum toxin type A injection

Cost effectiveness

No cost-effectiveness studies were identified for the use of botulinum toxin type A to treat chronic anal fissure in a UK setting were identified.

One US-based cost-effectiveness study (Essani et al. 2005) was identified. This study looked at the cost-saving effect of using a 3-step treatment escalation pathway. The pathway included first-line use of topical 0.2% GTN ointment, second-line botulinum type A injection (Botox, 2×20 units) and third-line lateral internal sphincterotomy. Each patient progressed through the pathway if treatment failed to improve symptoms or heal the fissure at the previous stage. A total of 67 adults were recruited. The study indicated surgery could be avoided in 88% of patients using this escalation pathway. Cost savings using the 3-step pathway were estimated at 41% compared with botulinum toxin type A alone followed by surgery if needed (excluding glyceryl trinitrate [GTN] use) and up to 70% compared with treating all patients with surgery. The study costs were based on US prices and are not directly applicable to the UK. None the less, they may be indicative of a reduction in surgery and associated cost savings in the UK through a similar approach. This would require further research in the UK to confirm.

Cost

The MIMS (May 2013) drug costs of botulinum toxin type A injection (Botox, Allergan Ltd) are £77.50 for a 50-unit vial, £138.20 for a 100-unit vial and £267.40 for a 200-unit vial. The MIMS cost for botulinum toxin type A injection (Dysport, Ipsen Ltd) was £92.40 for 300 units and £308.00 for 1000 units. The units are not equivalent across different brands of botulinum toxin type A.

Some studies of botulinum toxin type A used a single injection given in either side of the fissure, whereas others used 2 injections given as 1 injection on each side of the fissure. The most typical dose included in the studies in the Cochrane review was a single injection of 20 units of Botox. This would give an approximate drug cost of £77.50 per patient assuming wastage. This estimate is for the drug cost only and does not include cost of administration or specialist supervision. The Association of Coloproctology of Great Britain and Ireland points out that grouping patients on the same operating list and follow-up at the same outpatient clinic improves cost effectiveness because 1 vial can be used to treat more than 1 patient.

Although botulinum toxin type A is given in an outpatient department in some hospitals and in some of the studies reviewed, in the UK the majority of botulinum toxin type A treatment is given with the patient under general or regional anaesthesia in an operating theatre (Personal communication. Nelson R, Piramanayagam BApril 2013). These non-drug costs should be considered.

The NHS electronic drug tariff (May 2013) lists the price of the licensed treatment for anal fissure, 0.4% GTN (4 mg/g rectal ointment, ProStrakan), as £39.30 for 30 g. The Rectogesic 4 mg/g rectal ointment summary of product characteristics recommends a dose of 1.5 mg GTN (375 mg of ointment) applied intra-anally every 12 hours for up to 8 weeks. The cost of this 8-week treatment period would be £78.60 assuming wastage. As this is applied by the patient, there are no administration costs, so it is likely to be less expensive than botulinum injection overall.

The potential need for repeated botulinum injections or repeated 8-week cycles of GTN, as well as administration costs, should be factored into consideration of the relative costs of these 2 non-surgical treatments.

Current drug usage

Prescription Cost Analysis data show that from March 2012 to February 2013, 222 prescription items of botulinum toxin type A injections were dispensed in primary care in England, costing approximately £67,000 (Personal communication. NHS Business Services Authority May 2013). However, any off-label use of botulinum toxin A injection for anal fissure is most likely to be prescribed by hospitals and would therefore not appear in primary care prescribing data.

No information on the off-label use of botulinum toxin type A for chronic anal fissure was available at the time this evidence summary was prepared.

The British national formulary lists 6 botulinum toxin type A preparations that are licensed in the UK in adults. It states all should be used under specialist supervision and that unit doses are not equivalent between different brands:

Botox and Dysport are licensed for treating focal spasticity blepharospasm, hemifacial spasm, and spasmodic torticollis. Botox is also licensed for severe hyperhidrosis of the axillae, for the prophylaxis of headaches in adults with chronic migraine, and for managing urinary incontinence in adults with neurogenic detrusor overactivity caused by subcervical spinal cord injury (traumatic or non-traumatic) or multiple sclerosis, whose condition is not adequately managed with anticholinergics.

Azzalure, Bocouture, Botox, and Vistabel are licensed for the temporary improvement of moderate to severe wrinkles between the eyebrows in adults under 65 years. The Scottish Medicines Consortium has advised that Azzalure and Vistabel (December 2010), and that Bocouture (February 2011) are not recommended for use within NHS Scotland.

Xeomin is licensed for treating blepharospasm, spasmodic torticollis, and post-stroke spasticity of the upper limb.

In addition, the British national formulary states treatment with botulinum toxin type A can be considered after an acquired non-progressive brain injury if rapid-onset spasticity causes postural or functional difficulties.

Each botulinum toxin type A summary of product characteristics warns that the units (dose) of botulinum toxin are specific to each individual preparation and are not interchangeable with other preparations.

The British national formulary for children describes how botulinum toxin type A, used under specialist supervision, can be considered in children with an acquired non-progressive brain injury if rapid-onset spasticity causes postural or functional difficulties, and in children with spasticity in whom focal dystonia causes postural or functional difficulties or pain.