Purpose: Little experience exists with the use of arsenic trioxide in the treatment of recurrent, all-trans retinoic acid (ATRA)-resistant, acute promyelocytic leukemia (APL). The authors report a patient with multiply recurrent APL treated with arsenic trioxide (As2O3), which was administered as recommended in the protocol from the People's Republic of China. The results of this treatment and its toxicity are discussed. The available literature on arsenic therapy is reviewed.
Patients and Methods: The patient was a 15-year-old African-American girl with APL that had resisted conventional chemotherapy, ATRA therapy followed by autologous peripheral stem cell transplant, and a second course of ATRA induction therapy administered for relapse after transplant. The patient was treated with 10 mg As2O3 intravenously for 28 days. After a 4-week break, she received a second 28-day course of As2O3 therapy.
Results: After completion of the first 28-day course of As2O3 treatment, morphologic and cytogenetic remission occurred. Reverse-transcription polymerase chain reaction demonstrated persistence of the PML-RARa fusion transcript. After the second course of As2O3, the patient had a complete remission by morphologic, cytogenetic, and molecular criteria. Approximately 6 months after the end of two courses of As2O3 therapy, the patient again underwent relapse. An additional course of As2O3 achieved a morphologic, although not a cytogenetic or molecular, remission.
Conclusions: As2O3 therapy produced remission in a patient with multiply relapsed, ATRA-resistant APL. Toxic side effects were minimal. The patient underwent relapse 6 months after this therapy. Further investigation will be necessary to determine the proper role of As2O3 therapy in patients with APL.