Retinoic acid

Retinoic acid is a derivative of vitamin A. Two treatment forms of retinoic acid have been developed - all-trans retinoic acid and 9-cis retinoic acid.

All-trans retinoic acid influences the development of skin cells in laboratory studies. It is being examined as a potential treatment for Kaposi’s sarcoma, with encouraging results. Furthermore, there is preliminary evidence that all-trans retinoic acid may slow down cell death associated with HIV disease.¹

9-cis retinoic acid comes as either a topical gel or an oral formulation. The gel has been found to be moderately effective in treating Kaposi’s sarcoma lesions independently of CD4 cell count and antiretroviral therapy, producing a positive response in around a third of patients.^{2 3} In the United States, it was approved as a treatment for Kaposi’s sarcoma lesions in November 1998. The gel, known by the brand name Panretin, was developed by Ligand Pharmaceuticals.

Mild side-effects to the gel, primarily skin irritation, are common. Other common side-effects associated with the oral formulation are headache, dry or peeling skin, hair loss and high blood lipids. Rare cases of pancreatitis have been reported among people on high doses.

A capsule formulation of 9-cis retinoic acid has been tested for Kaposi’s sarcoma, but the side-effects, particularly headache, made it intolerable for most patients.^{4 5}