Isotretinoin Use During Consolidation in Acute Promyelocytic Leukemia Following Standard All-Trans Retinoic Acid (ATRA)-Based Induction: A Case Report.

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia characterized by the presence of the promyelocytic leukemia-retinoic acid receptor alpha (PML::RARA) fusion gene. The combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has significantly improved outcomes in patients with APL. Isotretinoin (13-cis retinoic acid), a stereoisomer of ATRA commonly used for acne vulgaris, shares a similar mechanism of action and has demonstrated differentiation-inducing activity in vitro and in limited clinical reports. We present the case of a 38-year-old uninsured male with low-risk APL, defined by a presenting white blood cell count of ≤10,000/µL per the Sanz risk stratification system, who achieved hematologic complete remission following standard induction therapy with ATRA plus ATO but was transitioned to isotretinoin during consolidation because he was unable to obtain ATRA due to financial constraints. The patient achieved molecular complete remission within two months of initiating isotretinoin-based consolidation therapy and continues to have negative PML::RARA reverse transcriptase polymerase chain reaction (RT-PCR) results, with sustained remission at 18 months of follow-up with ongoing molecular monitoring every three months. Although the concurrent use of ATO and prior ATRA-based induction are important confounders, this case highlights the potential role of isotretinoin as a cost-effective alternative retinoid for consolidation therapy in APL when ATRA is inaccessible, although ATRA remains the recommended standard treatment.