Background
Phase III RCT (CCG 3891). 379 patients (<36 months, or >18 months with MYCN amplification) with high-risk neuroblastoma. Two-phase randomized design: (1) myeloablative HDCT (TBI-based) vs continuation chemotherapy after induction; (2) isotretinoin (13-cis-retinoic acid) maintenance vs no further therapy. First trial to demonstrate benefit of HDCT and differentiation therapy in neuroblastoma.
Interventions and follow up
Arm A: Induction chemo → Myeloablative HDCT (carboplatin + etoposide + melphalan + TBI 10 Gy) + PBSC → local RT → isotretinoin OR observatio
Arm B: Induction chemo → Continuation chemotherapy → local RT → isotretinoin OR observatio
Primary endpoint: EFS
mFollow up: 10.6 years (long-term update)
Arm B: Induction chemo → Continuation chemotherapy → local RT → isotretinoin OR observatio
Primary endpoint: EFS
mFollow up: 10.6 years (long-term update)
Results
3-yr EFS (HDCT): 34% vs continuation 22%, P=.034
3-yr EFS (isotretinoin): 46% vs no maintenance 29%, P=.027
Long-term OS (10-yr, HDCT + isotretinoin): ~30% — modest long-term benefit
3-yr EFS (isotretinoin): 46% vs no maintenance 29%, P=.027
Long-term OS (10-yr, HDCT + isotretinoin): ~30% — modest long-term benefit
Adverse events
Main adverse events: HDCT: TBI-related — cataracts, growth failure, endocrine, secondary malignancies (AML). Isotretinoin: mucocutaneous toxicity, teratogenicity. Treatment-related mortality: 7% (HDCT arm). Late effects significant in long-term survivors.
Conclusions
Both myeloablative HDCT and isotretinoin maintenance independently improved EFS in high-risk neuroblastoma. This established the paradigm of HDCT consolidation followed by differentiation therapy that remains the backbone of current treatment.
Key Limitations
Key Limitations: TBI included in HDCT regimen — now replaced by CEM (carboplatin/etoposide/melphalan) due to long-term toxicity. Long-term OS remains disappointing (~30%) despite improved short-term EFS. Molecular subtyping not available to identify optimal candidates for intensification.
Clinical Context
CCG 3891 established myeloablative consolidation + 13-cis-RA as the standard two-component post-induction strategy for high-risk neuroblastoma. TBI has been replaced in modern protocols. Subsequent COG ANBL0032 added dinutuximab immunotherapy to further improve survival.