New drugs designed to improve efficacy, compliance

SAN FRANCISCO - A new class of drugs is being developed to fight bacteria, viruses and fungi, according to a presenter here at the Optometric Council on Refractive Technology meeting, held prior to the start of Academy 2010.

Aganocides are being developed for topical treatment of the eye, ear, skin and sinuses, Kelly Grosdidier, OD, of Durrie Vision, Overland Park, Kan., reported. "The antimicrobial molecules are designed to mimic the way the body's white blood cells fight infection," he said.

Novabay Pharmaceuticals is in clinical trials with NVC-422, Dr. Grosdidier said.

"It kills by destroying cell walls, proteins and nucleic acids," he said. "High kills rates have been shown. This might be another type of anti-infective we can use to treat our patients."

Dr. Grosdidier outlined the benefits of a number of other new agents.

Acuvail (ketorolac tromethamine 0.45%, Allergan) is a reduced concentration of traditional ketorolac tromethamine (0.5%) and was developed to enhance efficacy of previous formulations to reduce side effects and protect the cornea, Dr. Grosdidier said. It is approved for pain and inflammation following surgery and is dosed twice daily.

Carboxymethylcellulose was added and it was made preservative-free in a unit dose applicator.

Dr. Grosdidier performed a study of Acuvail in 10 patients who underwent bilateral PRK. Acuvail was placed in one eye and an artificial tear in the other twice daily for 4 days prior to surgery. Optovue OCTs were performed prior to surgery and at every postoperative visit. He said the primary endpoint was re-epithelialization and no pain.

"Preliminary results show that the Acuvail was clearly more comfortable," Dr. Grosdidier reported. "It was obvious which eye was which.

"OCTs were done every day until bandage contacts were removed," he continued. "We must still evaluate the OCTs, but at this point there does not appear to be a significant difference between the two groups."

Zymaxid (gatifloxacin 0.5%, Allergan) is a reformulation of Zymar (gatifloxacin 0.3%, Allergan) with a higher concentration.

"This is effective against gram-positive and gram-negative bacteria," Dr. Grosdidier said. "Designed to deliver more drug to the ocular surface, it has the same indications and similar dosing schedule to Zymar. One difference is that Zymaxid comes in a 2.5-mL bottle while Zymar is in a 5-mL bottle. It's preserved with BAK.

"We switched to this in all of our laser procedures in August," he added.

Another newer antibiotic is Besivance (besifloxacin 0.6%, Bausch + Lomb), which is formulated in Durasite to prolong contact time to the ocular surface, Dr. Grosdidier continued.

"This is not a new generation, but a 'first-in-class' chlorofluoroquinolone," he said. "This is an ophthalmic drug only. There is no systemic counterpart, so it should have reduced resistance."

Besivance is effective against methicillin-resistant Staphylococcus aureus, he said. "Studies have shown that Besivance is equivalent to vancomycin at treating MRSA."

Dr. Grosdidier added that a new formulation of Vigamox (moxifloxacin, Alcon) will be introduced soon. "It will have the same indications, spectrum of coverage and concentration," he said. "A new delivery system will allow for greater residency time and penetration."

Azasite (azithromycin 1% in Durasite, Inspire), another relatively new agent, can control meibomian gland dysfunction and improve the quality of meibomian gland secretions.

A newer antiviral, Zirgan (ganciclovir 0.15%, Bausch + Lomb), is indicated for acute herpetic keratitis. "It interferes with DNA replication of the virus in the cells, only targeting infected cells," Dr. Grosdidier said.

In the steroid category, Durezol (difluprednate 0.05%, Alcon) was initially developed as a topical dermatological agent, Dr. Grosdidier said. In June 2008 it was approved for inflammation and pain associated with ocular surgery. "It is expected to cause fewer ocular side effects," he said.

TobraDex ST (tobramycin 0.3%/dexamethasone 0.05%, Alcon) was designed to increase retention time on the surface of the eye.

In studies comparing TobraDex ST with the original TobraDex, ST has superior anti-inflammatory and bactericidal properties, he reported.

"Retention time is increased by suspension technology with xanthan gum," Dr. Grosdidier said. "It forms an ionic interaction in the bottle; on the eye, tears interrupt the interaction."

A new anti-allergy agent, Bepreve (bepotastine besilate 1.5% ophthalmic solution, Ista), was approved in late 2009 for ocular itching associated with allergic conjunctivitis. It has twice daily dosing and comes in a larger bottle (10 mL) than other anti-allergy agents, he said.

Dr. Grosdidier recommended Fluramene, a combination of fluorescein sodium 1% and lissamine green 0.5% sterile solution in a 15-mL bottle. "The single drop makes it easier to diagnose ocular surface disease - instilling one drop in the eye vs. trying to wet the lissamine green strip," he said. "This may make the strip a thing of the past. It's available from EyesupplyUSA.com."