Tetracaine

National report -- Results achieved in a series of studies comprising an extensive phase 3 clinical research program support the conclusion that a self-occlusive lidocaine 7 percent/tetracaine 7 percent peel (LT peel) provides safe, rapid and effective anesthesia for a broad spectrum of cutaneous procedures.

The presentations reported on use of the LT peel for achieving local anesthesia in adults prior to vascular access procedures, laser-assisted tattoo removal, laser-assisted hair removal, facial collagen injections, nonablative facial laser resurfacing, cryotherapy for actinic keratoses and pulsed dye laser treatment of facial vascular lesions.

Trial parameters

All of the trials had a randomized, double-blind, placebo-controlled design, and the number of patients enrolled ranged from 20 to 60. Their results showed consistently that the novel investigational product was well-tolerated and provided clinically useful local anesthesia based on patient visual analogue scale (VAS) ratings of pain, which was the primary efficacy endpoint, as well as in a number of secondary efficacy analyses.

"This local anesthetic peel has been fabulous in the premarketing clinical studies," says Tina S. Alster, M.D., who has been an investigator in several of the phase 3 trials as well as earlier studies of the topical anesthetic peel. "It is associated with a rapid onset of action and provides very deep dermal anesthesia that allows patients to tolerate supertidal surgery, such as laser treatment of telangiectasias or pigmented lesions, as well as more aggressive procedures, including ablative laser skin resurfacing."

Dr. Alster is director of the Washington Institute of Dermatologic Laser Surgery and clinical professor of dermatology, Georgetown University Medical Center.

She adds, "As our preferences move in the direction of using topical anesthesia whenever possible, I am looking forward to the commercial availability of this product. It is the best topical anesthetic I have ever used and will certainly- decrease the need for anesthetic injections."

How it works

The LT peel applies as a cream and dries when exposed to air to form a flexible film membrane that is easily peeled off prior to surgery. In most of the phase 3 studies, a 30-minute application time was used. That is much shorter than the duration of application needed for other topical anesthetic products, Dr. Alster notes.

"An earlier study we performed using a dose-response design showed that a 30-minute duration of application was at least as good as, if not better than, 60 minutes. The rapid onset of efficacy with this product is probably due to the fact that it is self-occlusive and improves penetration of the anesthetic agents, making this product an attractive option from the standpoint of increasing office efficiency with faster patient turnaround" she notes.

Dr. Alster was the lead author of a poster reporting on the use of the LT peel for dermal anesthesia prior to nonablative facial laser resurfacing at the American Academy of Dermatology's Academy '05. That multicenter study enrolled 40 patients and had a split-face design. Patients received concurrent 30-minute applications of the LT peel or placebo peel to the fight or left side of the face.

The VAS results showed the mean pain rating was significantly lower on the facial halves pretreated with the LT peel versus placebo (31.0 mm vs. 54.5 mm, respectively). In addition, more than four times as many patients reported adequate anesthesia with the LT peel versus with the control (78 percent versus 18 percent, respectively). According to the investigator ratings, no pain or slight pain was experienced by 93 percent of patients after use of the LT peel, compared with only 58 percent of those treated with placebo.

Favorable safety profile

In that study and across all the other trials, the LT peel has had a favorable safety profile. Some local skin reactions such as erythema, edema or skin discoloration occurred. However, they were generally minor, transient and similar in incidence compared with the placebo peel.

When the LT peel becomes available, Dr. Alster foresees additional uses.

"It may be especially helpful for patients undergoing punch biopsies or procedures like fractional skin resurfacing that tend to hurt quite a bit, and it will likely be a useful adjunct in pediatric offices prior to inoculations or other uncomfortable cutaneous procedures," she says.

The LT peel is being developed by Zars with the proposed trade name of TetraPeel. A new drug application has been submitted and is pending approval by the Food and Drug Administration.

Disclosure: Dr. Alster reports no financial interest in Zars, but says she did receive research support from the company.

CHERYL GUTTMAN

STAFF CORRESPONDENT

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