All-trans retinoic acid in combination with alpha-interferon and dexamethasone for advanced multiple myeloma.

The in vitro inhibitory effect of all-trans retinoic acid (ATRA) on myeloma cell growth may be synergistically potentiated by the activity of dexamethasone (DEX) and alpha-interferon (IFN). We treated 10 patients with advanced, refractory multiple myeloma (MM) using a combination of ATRA (100 mg p.o., once a day for two weeks every month), DEX (40 mg i.v., for 4 days every 4 weeks) and IFN (3 MU s.c., three times a week). Eight patients completed at least three months of treatment and were evaluable for response. Two of them showed a partial response which persists after 15 to 17 months. Three patients experienced a stable plateau phase of 4 to +11 months, with a significant improvement in the performance status and bone pain. Progressive disease was seen in the remaining three patients. We conclude that the association of ATRA, DEX and IFN warrants further consideration in MM patients.