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Updated: Dec 18, 2025
06:24
Minimal Erythema Dose MED Testing
Published on: May 28, 2013
42.6K
Vemurafenib-related photosensitivity.
Bernadette Eberlein1, Tilo Biedermann1, Rüdiger Hein1
1Department of Dermatology and Allergology, Biederstein, School of Medicine, Technical University, Munich, Germany.
Summary
Vemurafenib causes significant photosensitivity, primarily due to UVA radiation, leading to immediate and delayed skin reactions. Patients require counseling on photoprotection against UVA exposure.
Area of Science:
- Dermatology
- Pharmacology
- Photobiology
Background:
- Vemurafenib, a BRAF inhibitor, commonly causes photosensitivity.
- This adverse effect presents as immediate heat/erythema and delayed sunburn reactions upon sun exposure.
Purpose of the Study:
- To investigate the mechanisms of vemurafenib-induced photosensitivity.
- To compare photosensitivity risks with other BRAF inhibitors.
Main Methods:
- Phototesting to identify effective UV wavelengths.
- Photochemical and in vitro studies to elucidate pathogenic mechanisms.
- Clinical observation and comparison with other BRAF inhibitors.
Main Results:
- UVA radiation (320-400 nm) triggers both immediate and delayed reactions.
- Vemurafenib forms a UVA-absorbing photoproduct, causing phototoxicity.
- Vemurafenib inhibits ferrochelatase, increasing protoporphyrin IX, though its role in immediate reactions is unproven.
Conclusions:
- UVA radiation is the primary cause of vemurafenib-induced photosensitivity.
- Vemurafenib's phototoxicity is linked to UVA-induced photoproduct formation.
- Patients on vemurafenib must be informed about UVA risks and advised on photoprotective measures.
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