Gauging ganciclovir gel for herpes virus

Ganciclovir gel is effective for herpes simplex epithelial keratitis, and emerging evidence shows it also can be used to treat other corneal disease.

Reviewed by Kristin Hammersmith, MD

Philadelphia-There is good evidence that topical ganciclovir gel (Zirgan, Bausch + Lomb) can help treat herpes simplex epithelial keratitis, said Kristin Hammersmith, MD.

There is also emerging evidence about the gel’s role in the treatment of other herpes viruses, including varicella zoster, cytomegalovirus, and adenovirus, according to Dr. Hammersmith, fellowship director, Cornea Service, Wills Eye Hospital, and associate professor, Thomas Jefferson University, Philadelphia.

The addition of ganciclovir gel to the treatment armamentarium in 2009 after FDA approval was welcome by ophthalmologists because of the side effects associated with other treatments, Dr. Hammersmith said.

“Over the last 50 years, we’ve had limited topical options for herpes keratitis,” she said.

Previous treatments have been associated with some risk for conjunctival inflammation and corneal erosion rates.

Conjunctival toxicity from topical vidarabine use in topical treatment of herpes viruses. (Image courtesy of Kristin Hammersmith, MD)Ganciclovir works similarly as acyclovir. The agent is phosphorylated, contributes to less toxicity and is generally well tolerated. It also has a similar tonicity to tears and a long and stable shelf life.

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The approved use is five times a day until the dendrite is healed and then three times a day for seven days.

Exploring use with other viruses

However, there is still plenty of room to explore how well it works to treat various herpes-related problems, Dr. Hammersmith noted.

The treatment appears effective for epithelial keratitis, Dr. Hammersmith said, citing evidence from four multicenter trials that looked at ganciclovir and acyclovir that found equal rates of recovery and healing times.

A Cochrane review article published last year analyzed 137 studies with more than 8,000 patients and found 29 studies that specifically used topical ganciclovir.¹ Although the investigators concluded that ganciclovir was at least as effective as acyclovir for the treatment of epithelial keratitis, they added that any potential advantage was mitigated by study heterogeneity and possible publication bias.

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There is also some evidence to measure the effect of ganciclovir after penetrating keratoplasty (PK).

Prospective study

Dr. Hammersmith discussed a 2005 prospective study from Tabbara²with six patients, half of whom were post-PK. Ganciclovir 0.15% was used twice a day for a year. There were no recurrences in the group with prophylaxis; the recurrence rate was 30% in the untreated group.

Corneal toxicity from topical vidarabine use in topical treatment of herpes viruses. (Image courtesy of Kristin Hammersmith, MD)

“It may be helpful in prophylaxis with or without PK,” she said. “This is small evidence, but it’s interesting.”

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There is also small but growing evidence about the use of ganciclovir to treat other types of herpes and adenovirus. Ganciclovir gel may be helpful to treat pseudodendrites associated with varicella zoster keratitis. And there is limited positive evidence for its use in treating adenovirus, a common problem with few treatment options.

The clinical application of ganciclovir gel still is ripe for investigation.

“There are lots of areas of opportunity for research to enhance our understanding of utility in other applications,” Dr. Hammersmith said.

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References

1. Wilhelmus KR. Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis. Cochrane Database Syst Rev. 2015;9;1:CD002898.

2. Tabbara KF. Treatment of herpetic keratitis. Ophthalmology. 2005;112:1640.

Kristin Hammersmith, MD

E: kristinhammersmith@hotmail.com

This article was adapted from Dr. Hammersmith’s presentation during Cornea Subspecialty Day at the 2015 meeting of the American Academy of Ophthalmology. Dr. Hammersmith has no financial interests related to her comments. Her presentation addresses some off-label uses of ganciclovir gel.