CD33 expression on myeloblasts in newly-diagnosed AML (favorable / intermediate cytogenet...

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

ID	`RF-AML-CD33-POS-GO-CANDIDATE`
Type	Red flag
Status	reviewed 2026-04-29
Diseases	`DIS-AML`
Sources	`SRC-ALFA-0701-CASTAIGNE-2012` `SRC-ESMO-AML-2020` `SRC-NCCN-AML-2025`

Red Flag Origin

Definition	CD33 expression on myeloblasts in newly-diagnosed AML (favorable / intermediate cytogenetic risk; non-APL) — CD33 expressed on >85% of AML blasts; quantitative flow / IHC threshold not formally required but high-MFI cohorts derive greatest benefit. Gates gemtuzumab ozogamicin (GO; anti-CD33 calicheamicin ADC) addition to 7+3 induction. ALFA-0701 (Castaigne 2012 Lancet): fractionated GO 3 mg/m² days 1/4/7 + 7+3 in de-novo AML — EFS HR 0.58, OS HR 0.69, greatest benefit in favorable + intermediate cytogenetics; no benefit in adverse cytogenetics. Excluded: APL (PML-RARA — different therapy), adverse cytogenetics (TP53/CK/-7/-5q — VOD risk + no efficacy signal), prior allogeneic HCT.
Clinical direction	intensify
Category	high-risk-biology

Trigger Logic

{
  "all_of": [
    {
      "any_of": [
        {
          "finding": "cd33_expression",
          "value": "positive"
        },
        {
          "finding": "cd33_status",
          "value": "expressed"
        },
        {
          "finding": "cd33_flow",
          "value": "positive"
        },
        {
          "comparator": ">=",
          "finding": "cd33_blast_percent",
          "threshold": 20
        }
      ]
    },
    {
      "any_of": [
        {
          "finding": "newly_diagnosed_aml",
          "value": true
        },
        {
          "finding": "aml_treatment_naive",
          "value": true
        }
      ]
    },
    {
      "any_of": [
        {
          "finding": "cytogenetic_risk",
          "value": "favorable"
        },
        {
          "finding": "cytogenetic_risk",
          "value": "intermediate"
        },
        {
          "finding": "eln_2022_risk",
          "value": "favorable"
        },
        {
          "finding": "eln_2022_risk",
          "value": "intermediate"
        }
      ]
    }
  ],
  "type": "composite_score"
}

Notes

Fractionated GO dosing (3 mg/m² days 1/4/7) — single-dose 6 mg/m² schedule (used in early SWOG-S0106) was abandoned due to VOD/SOS excess; ALFA-0701 fractionation is current standard. Hepatic veno-occlusive disease (VOD/SOS): ~1-2% with fractionated dosing, higher in adverse-cytogenetics + post-alloHCT subjects. Defibrotide is treatment of choice. Concomitant TLS prophylaxis (high-leukocytosis AML). Exclusion: APL (separate algorithm — ATRA + arsenic), CBF-AML may benefit even in ASCEND/AMLSG protocols. Pediatric/ young-adult use: mixed evidence — UK MRC AML17 supportive, COG-AAML0531 supportive in standard-risk pediatric. Ukrainian access: GO available via funded reimbursement post-2020 NSZU inclusion (verify current status). STUB — requires clinical co-lead signoff.

Used By

No reverse references found in the YAML corpus.