Vitamin A Analogues
In studies, a vitamin A analogue, retinoic acid, has activity against minimal residual neuroblastoma (disease that can not be identified by routine methods).
May work even in tumors that are resistant to chemotherapy and/or radiation.
Retinoic acid works by:
- Decreasing proliferation
- Decreasing expression of N-MYC
- Causing morphologic differentiation (from immature Neuroblastoma to the more mature form)
Toxicities include:
- Cheilitis
- Dry skin
- Hypertriglyceridemia
- Hypercalcemia
In a randomized trial (CCG-3891), patients with high risk neuroblastoma were randomly assigned to receive a 6 month course of isotretinoin versus observation alone (after chemotherapy and autologous bone marrow transplant). The 3 year event free survival, for the patients who received isotretinoin was about 50% vs 35% for those who did not. The difference was not statistically significant, but there was a strong trend towards improved survival with isotretinoin.
Retinoic Acid has now been incorporated into the standard treatment for high risk neuroblastoma.
