A relapsed/refractory acute promyelocytic leukemia achieving complete response after chemotherapy with venetoclax.

RATIONALE: The vast majority of patients newly diagnosed with acute promyelocytic leukemia (APL) can achieve complete response (CR) through induction therapy that includes all-trans retinoic acid (ATRA), and subsequently achieve molecular response after consolidation therapy. Relapses are quite rare after achieving molecular response. Nonetheless, 5% to 10% of APL patients who receive ATRA plus anthracycline chemotherapy may experience relapse. Compared to newly diagnosed APL patients, the treatment of relapsed/refractory APL remains a challenge due to its rarity. This article reports a case of an APL patient with multiple relapses who achieved complete response following chemotherapy with venetoclax (VEN) in combination with idarubicin and cytarabine. PATIENT CONCERNS: The patient is a 58-year-old male who was definitively diagnosed with acute promyelocytic leukemia 20 years ago. One month ago, he presented with gum bleeding. A bone marrow examination revealed that abnormal promyelocytes accounted for 58.0%, and a complete blood count indicated pancytopenia. DIAGNOSES: The patient has a definitive diagnosis of relapsed/refractory APL, complicated by a DNMT3A mutation and complex karyotype, indicating a poor prognosis. INTERVENTIONS: Complete response was achieved after the salvage chemotherapy, specifically: VEN 100 mg day 4, 200 mg day 5, 400 mg days 6-11; Idarubicin 20 mg days 1-2; Cytarabine 100 mg bid days 1-5. OUTCOMES: After VEN-based therapy, the patient exhibited no symptoms of leukemia and had achieved complete response. LESSONS: For relapsed and refractory APL, relevant drug resistance gene monitoring should be carried out. Some relapsed and refractory APL patients who do not respond to conventional treatment are at risk of death. We report a successful case, the regimen of VEN targeted therapy combined with chemotherapy still holds promise for the treatment of future relapsed/refractory APL.