5-Aminolevulinic Acid (5-ALA)

5-Aminolevulinic acid (5-ALA, delta-Aminolevulinic acid) is used in the photodynamic therapy against actinic keratosis and basal cell carcinoma. Biosynth is approved to manufacture 5-Aminolevulinic acid for the use as an active pharmaceutical ingredient (GMP, A-6105). We have also compiled data for both the open and closed parts of the drug master file, and the DMF open part is now available on request.

Basal cell carcinoma

Every year millions of basal cell carcinoma cases are diagnosed making it the most common form of cancer encountered. Basal cell carcinomas rarely metastasize and are generally not life threatening. Unfortunately they can spread to lower layers of skin unnoticed causing complications significant enough to require surgical removal of the cancerous tissue. The areas of skin most commonly affected by basal cell carcinoma are nose, upper lip, ears and other extremities extensively exposed to sunlight unprotected. As a result the areas most susceptible to these carcinomas are also very sensitive from a cosmetic perspective.

Actinic keratosis

Actinic keratosis – also known as sun spots – refers to a precancerous skin condition. Sun spots are harmless per se but have the potential to develop into malignant skin cancer (squamous cell carcinoma) if left untreated. It is believed that 20% of the world population will develop precancerous tissue in the next 40 years.


Affected skin is generally treated by removal of the necrotic tissue. A cream containing 5-Aminolevulinic acid (5-ALA) is applied and allowed to penetrate into the skin for several hours. Subsequent exposure to light of the appropriate wavelength causes the selective apoptosis of (pre-) cancerous tissue. Unfortunately, the photodynamic therapy of actinic keratosis and basal cell carcinoma is not yet covered by health insurances. Currently, health insurances still favour the less effective and much more expensive surgery over the non-invasive low cost treatment based on 5-ALA. A broad change in insurance policy in favor of the less invasive and less costly treatment is expected in the near future.

Mechanism of action

5-ALA is a key metabolite in porphyrin (heme) synthesis. High levels of 5-ALA stimulate the cellular production of protoporphyrin IX (PP 9), an intermediate in the biosynthesis of heme. PP 9 is an effective photosynthesizer that converts oxygen from air into its toxic form (singlet oxygen) upon irradiation with red light. Singlet oxygen acts as an intracellular toxin. Due to increased levels of metabolic activity topically applied 5-Aminolevulinic acid (5-ALA) is taken up by cancerous cells most effectively allowing them to be killed selectively. This means that unaffected tissue remains unharmed and intact while the cancerous tissue around it is being destroyed by the treatment.

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