Patients who cannot tolerate an anthracycline drug may get ATRA plus another drug called arsenic trioxide. Arsenic trioxide has also proven to be an effective alternative for the 20% to 30% of patients with APL who don't respond to initial treatment or who relapse. If treatment with arsenic trioxide achieves a remission, further courses of this drug may be given. An autologous stem cell transplant may also be an option. If a second remission is not achieved, treatment options may include an allogeneic stem cell transplant or taking part in a clinical trial.