Purchase this article with an account.
J. Hill, P. Cusimano, W.J. Snyder, N.J. Razum; Intensity and Duration of Dermal Photosensitization With Rostaporfin (SnET2, or Photrex) Photodynamic Therapy (PDT): Results of Two Solar Simulation Studies . Invest. Ophthalmol. Vis. Sci. 2005;46(13):310.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To report the results of two dermal sensitivity studies using simulated solar radiation in patients sensitized with varying doses of rostaporfin (SnET2, or PhotrexTM). Photrex is a lipophilic photosensitizer that is under investigation for the treatment of choroidal neovascularization secondary to age–related macular degeneration (AMD). Methods: Subjects received baseline solar simulator exposure prior to rostaporfin infusion to allow them to serve as their own controls. In one study, 12 healthy subjects were infused with rostaporfin at either 0.3 mg/kg (n=4), 0.6 mg/kg (n=4), or 1.2 mg/kg (n=4). At 6 defined times over the following 1–month period they were exposed to light doses of 22, 44, 66, and 88 J/cm2 (equivalent to 15, 30, 45, and 60 minutes exposure to noonday sun in the US) of filtered light from a certified simulated solar light source). In the second study, 17 healthy subjects were infused with rostaporfin at a dose of 1.6 mg/kg, followed by the exposure to the same light doses at 7 defined times over 1 month. Exposed areas were evaluated at 24 ± 2 hours after each exposure with a scoring system that rated the photosensitivity reaction as 0 (no response), 0.5 (minimal perceptible erythema with indistinct borders – MPE), 1 (minimal erythema with defined borders, equivalent to the Minimal Erythemal Dose – MED), 2 (obvious erythema with no edema), 3 (erythema with some edema), or 4 (marked erythema with edema and vesiculation). Results: The intensity of dermal responses was found to increase with increasing drug dose and simulated solar light dose. For all drug doses, dermal responses were found to be maximal at 2 days following administration, declining thereafter. At most time points, the majority of patients had mild reactions scored as either MPE or 1 (MED). The duration of the photosensitivity period was 5 to 6 days at the low drug doses (0.3 and 0.6 mg/kg) and between 1 to 2 weeks at higher doses (1.2 and 1.6 mg/kg). Conclusions: Rostaporfin–associated photosensitivity was drug and light dose–related. At lower doses (0.3 and 0.6 mg/kg) the photosensitivity reactions were of mild intensity characterized by minimal erythema and were of short duration. The higher photosensitizer doses (1.2 and 1.6 mg/kg) were associated with moderate erythema and somewhat lengthened duration of response. The results of these studies support solar precautions (protective clothing and eyewear) for a period of 5 to 6 days following a dose of 0.5 mg/kg as proposed for Photrex–PDT of AMD and up to 2 weeks for higher doses used in other indications.
This PDF is available to Subscribers Only