- Lenalidomide is a drug that may help reduce or prevent the growth of cancer cells. Dexamethasone is a steroid that is often given with other anti-cancer drugs. These two drugs are an approved treatment for multiple myeloma that has not responded to at least one other treatment. Carfilzomib is an experimental drug that has been effective in treating multiple myeloma. Researchers want to combine these three drugs to see if they are a safe and effective treatment for SMM.