Retinoic acid

Topical and oral retinoic acid has been tested for treatment of KS, and there is evidence that about one-third of people with KS lesions respond to this treatment.

A number of studies have shown that 9-cis-retinoic acid, or alitretinoin, gel (Panretin) is effective in treating KS lesions. An American study found a 39% response rate to retinoic acid gel in an intention-to-treat analysis.1

Two twelve week randomised, placebo-controlled studies of retinoic acid gel have been conducted. In one study, the gel was applied twice daily, giving a response rate to the gel of 37%, while 44% remained stable and 19% progressed. In comparison, 7% of patients on placebo had a response, 58% remained stable and 35% progressed. In the other study, retinoic acid gel was applied three times daily, escalating to four times daily in the absence of side-effects, and found similar results. In both studies, resolution of KS occurred across a range of CD4 cell counts and was independent of antiretroviral therapy, although there was a correlation between higher CD4 cell counts, protease inhibitor therapy, and positive response to retinoic acid gel.

Alitretinoin gel may cause skin irritation and skin pigment lightening around the site of application.

Alitretinoin gel was given licensing approval in the United States as a topical treatment for Kaposi's sarcoma in November 1998. It is not licensed in Europe.

Retinoic capsules have been developed for oral administration, but they cause significant toxicity.

References

  1. Thommes J et al. Phase II study (protocol L1057-28) of Panretin capsules (LGD1057, ALRT1057) for AIDS-related Kaposi's sarcoma. 12th World AIDS Conference, Geneva, abstract 22278, 1998