High-risk acute promyelocytic leukaemia (APL) — defined by a white blood cell count above 10 ×10⁹/l — is a distinct clinical subgroup requiring a specific treatment strategy. This protocol applies when the prior treatment line in this setting did not achieve complete remission.

Clinical Scenario

Acute promyelocytic leukaemia with WBC count >10 ×10⁹/l (high-risk). Patients meeting this threshold are treated with ATRA-based combination regimens or conventional anthracycline-based chemotherapy-containing approaches, as specified in the guideline.

Prior Therapy & Failure Condition

The preceding line for high-risk APL involves either ATRA plus ATO combined with an anthracycline, or conventional ATRA plus anthracycline-based chemotherapy (e.g. ATRA and idarubicin — AIDA). This protocol represents the next step when that approach did not yield complete remission.

Treatment Approach (Partial Overview)

In certain regimens used in this setting, a structured maintenance phase follows the induction and consolidation phases — the specific components, sequence, and duration are defined in the full protocol.

References

APL high-risk patients defined by a WBC count >10 ×10⁹/l may be treated with either ATRA plus ATO combined with an anthracycline (while ATO is not approved for high-risk APL) or with conventional ATRA plus anthracycline-based ChT [e.g. ATRA and idarubicin (AIDA)] [II, A] (see supplementary Table S6, available at Annals of Oncology online).

In the AIDA regimen, the induction and consolidation treatments are followed by a 2-year maintenance phase.

If ATO is not available/affordable for first-line treatment, the classical combination of ATRA and anthracycline-based ChT is still an acceptable option, which however requires 2-year maintenance therapy with methotrexate and 6-mercaptopurine.

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Treatment of AML in High-Risk Acute Promyelocytic Leukaemia (WBC >10 ×10⁹/l) When Prior Therapy Did Not Achieve Complete Remission

References