A Pilot of Pediatric/Adult Study of Gene Expression Profiling and Clinical Characterization of Phototoxicity

Healthy Volunteers Clinical Trial

Official title: A Pilot Pediatric/Adult Study of Gene Expression Profiling and Clinical Characterization of Phototoxicity

Status Completed

Clinical Trial Summary

This study will examine the phototoxicity, a reaction to light that is like exaggerated sunburn, which occurs in people who take medications such as voriconazole, a medication used to fight fungus. Sunscreens might protect the skin from the reaction. Although phototoxicity from voriconazole is not completely understood, it may be related to how that medication is metabolized in the liver by enzymes called cytochrome P450 enzymes-and mainly by one known as 2C19. A way to evaluate phototoxicity is through microarrays, which measure how much each gene is expressed in cells from tissues such as skin.

Patients ages 8 and older who are scheduled to begin taking or who currently take voriconazole may be eligible for this study. Also, patients ages 18 to 45 in good health who have skin tone known as Type 2, which usually burns and tans only slightly following sun exposure, may be eligible. All patients will visit the Dermatology Clinic. They will complete two questionnaires, on medical history and medications, as well as the skin response to sunlight, and donate about 3 teaspoons of blood. Patients who are scheduled to take voriconazole will visit the clinic four times, that is, two visits 2 consecutive days before beginning the medication and two visits on 2 consecutive days after taking it for at least 7 days. Each visit will take 1 to 2 hours. Patients about to take voriconazole will have a blood test and undergo a physical exam of the skin test site, on the buttocks. Researchers will take photographs of the specific site and do tests to measure skin reaction to ultraviolet (UV) light. UV light will be shined on 15 small areas of the skin, each 1 x 1 centimeters. After 24 hours, any redness that occurs on the skin will be checked. Afterward, patients will begin taking voriconazole according to directions by the researchers. At 10 or more days later, patients will visit the clinic. Sunscreen will be applied and 1 hour later after administration of voriconazole, a blood sample will be drawn to check the level of medication. Then UV light will be shined on 23 areas of skin 1 x 1 centimeters. More photographs will be taken of test sites to record changes in skin redness. On the next day, the skin response will be evaluated. Participants in the control group will be asked to avoid UV radiation by wearing hats and clothing, and using sunscreen. They will be given the doxycycline, an antibiotic, and undergo procedures with UV light shined on small areas of the skin, on the buttocks. Control participants will have 7 study days, with visits lasting from 1 to 3 hours and probably not exceeding 8 hours. They will have two shave biopsies on Study Day 2 and on Study Day 7 to determine how the skin has responded to UV light exposures.

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Clinical Trial Description

Background:

• Phototoxicity is a sunburn-like response associated with certain medications and is a phenomenon which is not completely understood. Although clinically similar to a typical sunburn reaction, the gene expression changes in phototoxic skin reactions may differ from those in typical sunburn.

• Doxycycline is a relatively well-tolerated and known phototoxic antimicrobial which can be used in healthy volunteers to increase susceptibility to phototoxicity.

• Characterizing potential risk factors to phototoxicity secondary to voriconazole, a broad-spectrum antifungal agent associated with potentially treatment-limiting phototoxicity, may allow identification of subjects at risk for the adverse reaction via pharmacogenetic evaluation and medical record review.

• Subjects at risk of phototoxicity may benefit from application of effective sunscreens.

Objectives:

• To determine the global gene expression profiles in skin exhibiting phototoxic reactions in healthy volunteers treated with doxycycline, and compare expression profiles in skin exposed to ultraviolet (UV) radiation occurring in the absence of doxycycline.

• To investigate the effects of the doxycycline alone in the skin of phototoxic and non-phototoxic healthy volunteers.

• To characterize voriconazole-related phototoxicity reactions in subjects with the use of phototesting and to determine if these subjects may receive reasonable phototoxic protection from the use of sunblock.

Eligibility:

• I & II) Healthy volunteers with skin phototype II.

• III) Subjects scheduled to begin voriconazole therapy.

• IV) Subjects on chronic voriconazole with or without a history of phototoxicity reaction.

• Previously treated healthy volunteers (I & II) who were evaluated to be either phototoxic

OR non-phototoxic.

Design:

• I) For the Screening visit arm, forty healthy volunteers will undergo screening with pertinent skin exam and blood work to evaluate ANA/ENA and liver function profile.

• II) For the Study visit arm, eligible healthy volunteers will undergo phototesting and will have skin biopsies prior to initiating a 3-day course of oral doxycycline 100 mg twice daily.

• After the last dose of doxycycline, healthy volunteers will undergo on-treatment MED testing.

• In those demonstrating phototoxicity, skin biopsies will be performed and submitted for processing for microarray analysis.

• III) Thirty-five subjects scheduled to begin voriconazole will undergo CYP450 genotyping and baseline phototesting prior to initiation of voriconazole.

• Adult subjects will be invited to undergo optional skin biopsies pre-drug and on-drug.

• Repeat phototesting will be performed in subjects after at least 7 days of voriconazole to determine if voriconazole predisposes to phototoxicity.

• Subjects with voriconazole phototoxicity will be invited to undergo sunscreen testing.

• IV) Seventy subjects with prior clinical history of voriconazole phototoxicity as well as known voriconazole phototoxicity non-reactors will undergo CYP450 genotyping and potential phototesting.

• To investigate the effects of the doxycycline alone in the skin of healthy volunteers previously categorized as phototoxic and non-phototoxic ;

Related Conditions & MeSH terms

• Bacterial Infections
• Communicable Diseases
• Dermatitis, Phototoxic
• Fungal Infections
• Healthy Volunteers
• Infections
• Mycoses

• NCT number: NCT00353158
• Study type: Interventional
• Source: National Institutes of Health Clinical Center (CC)
• Status: Completed
• Phase: Phase 1
• Start date: May 25, 2007
• Completion date: September 20, 2011