Pragmatic and Profound Benefits of Acyclovir Buccal Adhesive Tablets

Recurrent “cold sores” or “fever blisters,” as they are commonly called, are painful, unsightly, embarrassing, and distressful for those who experience them. In fact, oro-labial herpes simplex infections are among the two most stigmatizing of all cutaneous disorders.¹ Rapid relief of symptoms associated with labial herpes outbreaks and similarly prompt resolution of visible lesions is important. There are many ways to accomplish this, both through the application of prescription and over-the-counter topical antiviral preparations and via the administration of oral acyclovir and its analogues. While immediate alleviation of signs and symptoms as well as interfering with progression from prodrome to overt vesiculation are desirable, to the labial herpes sufferer, primary prevention of recurrence is even more attractive. To date, however, the aforementioned interventions have not proven particularly effective in this regard. For example, Rooney, et al.² found that oral administration of twice daily acyclovir (400mg per dose) over a four-month time span led to a mean duration of 118 days before the next outbreak, as compared to 46 days in those patients taking a placebo. While a 53% reduction in the number of clinical recurrences is certainly a positive result, this required twice daily ingestion of medication over a protracted time period. We are all aware that adherence falls off significantly over time for virtually all skin diseases, especially when the patient is expected to take (or apply) medication every single day.

By contrast, a single administration of the relatively new product consisting of 50mg acyclovir in a buccal adhesive tablet delivery system (ABT-50mg) not only led to an increase in aborted attacks compared to a placebo adhesive tablet, but also led to a delay in time until the subsequent outbreak.³ In fact, those subjects in this pivotal Phase 3 trial who received the active product had a mean improvement of 105 days free from cold sores compared to placebo.³ Reliance on this simple, single-dose acyclovir therapy should enhance compliance while also obviating worries about potentially serious systemic ramifications (such as nephrotoxicity⁴) since plasma levels of drug are quite low.⁵ It is reasonable to speculate that this particular acyclovir dosage form achieves clinical benefit due to a locally-targeted antiviral assault. Despite low acyclovir plasma concentration, the buccal adhesive tablet provides extremely high concentrations in saliva and both oral and labial tissue.⁵ In this manner, the overall viral load may be reduced by addressing the likely HSV-1 reservoirs not only in the trigeminal ganglia but in both the peripheral nerves and soft tissues.

Although the pivotal clinical study and associated pharmacokinetic studies are promising, the question for the clinician should still remain: how well does this muco-adhesive acyclovir tablet work in real life? Does ABT-50mg perform in a similar fashion when used on “normal” individuals who are not engaged in a clinical research study? To this end, I present several illustrative cases.

A 23-year-old Hispanic female graduate student was employed part-time as a medical receptionist. She had suffered from labial herpes for approximately ten years, with painful attacks always