Naxitamab Received FDA Approval for High-Risk Neuroblastoma

A New Chapter Targeting GD2 in High-Risk Neuroblastoma: Naxitamab-gqgk (Danyelza), Five Years of Development from FDA Approval to the NCCN 2025 Guidelines

The most challenging solid tumor of childhood

Neuroblastoma is a solid tumor arising from immature neuroblasts of neural crest origin in the sympathetic nervous system; it is the most common extracranial solid cancer of childhood. Most cases are diagnosed before age 5; the median age at diagnosis is approximately 18 months. Its clinical behavior is highly variable: at one extreme are infant cases with stage 4S disease (involvement of bone marrow, skin, and liver, but with possible spontaneous regression), and at the other are high-risk stage 4 cases in adolescents and preschool children (extensive bone/bone marrow metastases and poor prognosis).

The “high-risk” category is defined using the International Neuroblastoma Risk Group (INRG) and the older International Neuroblastoma Staging System (INSS) criteria. The classic high-risk criteria are:

The current standard treatment approach for high-risk neuroblastoma is multidisciplinary and consists of four main phases: (1) induction chemotherapy (combinations based on cyclophosphamide, topotecan, vincristine, doxorubicin, etoposide, and cisplatin; COG ANBL cohorts); (2) surgical resection of the primary tumor; (3) consolidation — high-dose chemotherapy + autologous hematopoietic stem cell transplantation (ASCT), sometimes tandem ASCT; (4) the maintenance phase — anti-GD2 immunotherapy + retinoic acid + IL-2 and/or GM-CSF. Since Yu et al.'s 2010 NEJM study, the maintenance phase has included an anti-GD2 monoclonal antibody. Naxitamab is the second antibody to enter this setting, but particularly relapsed/refractory patients form its main indication for which accelerated approval was granted.

Why GD2? The molecular signature of neuroectodermal tumors

GD2is a disialoganglioside— a complex glycosphingolipid molecule containing two sialic acid groups. It is highly expressed in tissues of embryological neural crest origin: neuroblastoma, melanoma, small-cell lung carcinoma, glioblastoma, retinoblastoma, and mesenchymal sarcomas, particularly osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma. In healthy adult tissues, GD2 expression is limited to certain parts of the central nervous system, peripheral nerve fibers, and skin melanocytes. This asymmetry of expression makes GD2 an ideal target for antitumor immunotherapy, but it is also the main source of its adverse-effect profile.

The first anti-GD2 monoclonal antibody was dinutuximab(Unituxin, United Therapeutics), approved by the FDA in 2015 for maintenance therapy of high-risk neuroblastoma. Dinutuximab is a chimeric IgG1 antibody, meaning it is half mouse-derived and half human-derived. This chimeric structure leads the immune system to recognize it as “foreign” and causes infusion reactions and pain responses. Dinutuximab requires a continuous IV infusion lasting 10 hours in each cycle, making hospitalization mandatoryand placing a considerable burden on families throughout treatment (admission, accompanying caregiver, accommodation).

Naxitamab was developed to reduce this burden. Hu3F8 is the clone designation of this humanized anti-GD2 IgG1 monoclonal antibody; only its CDR (complementarity-determining region) is mouse-derived, while the rest of the backbone is human IgG1. This humanized structure: (a) reduces immune reactions; (b) has 10-fold higher binding affinitythan dinutuximab; and (c) can be administered over a shorter infusion time (approximately 30-60 minutes). This third feature makes outpatient administration possible.

Summary of the pivotal data

FDA approval is based on two single-arm, open-label studies:

According to long-term follow-up data reported by Targeted Oncology, Study 201 reported 1-year progression-free survival (PFS) of %37,0 (%95 CI: %21,8-%62,9), a median time to progression of 9,2 months, and 1-year overall survival (OS) of %55 (%95 CI: %39,4-%76,9).

Mora et al., Sant Joan de Déu, 5-year follow-up

Perhaps the most interesting real-world evidence outside naxitamab's FDA approval comes from the compassionate-use program conducted by Jaume Mora's team at Hospital Sant Joan de Déu in Barcelona. Outside the FDA-approved indication, this program tested consolidation in patients with high-risk neuroblastoma in first complete remission using naxitamab + GM-CSF. Unlike the standard approval, patients were not at the final response stage of treatment but had entered complete remission after induction chemotherapy + ASCT and received naxitamab consolidation.

In the updated analysis published by Mora et al. in 2023 in the journal Cancers (DOI:10.3390/cancers15092535):

These figures are markedly above historical reference values for high-risk neuroblastoma (5-year OS around %50-60 and EFS %40-50). The Mora team's observation is important: some patients in this cohort had not even received ASCT; only induction chemotherapy + surgery + naxitamab consolidation. This challenges the classic high-risk NB treatment paradigm: how necessary is ASCT when naxitamab is available?

Adverse-effect management: practical aspects of pain and infusion reactions

The FDA approval document for naxitamab includes a boxed warning . There are two critical adverse effects that could be regarded as the “signature” of anti-GD2 immunotherapy: infusion reactions and pain.

Pain is a natural extension of naxitamab's mechanism of action; antibody binding to GD2 in the myelin sheath of peripheral nerve fibers triggers neuropathic pain signals. This is a biologically unavoidable, dose-dependent adverse effect. The first few infusions cause the most severe pain; tolerance may develop in later cycles.

Other important safety warnings:

• Transverse myelitis: 1 case (Grade 3) has been reported. Naxitamab must be permanently discontinued if this syndrome develops.
• Severe hypertension: Onset can be delayed. Blood pressure monitoring during and after infusion is mandatory. Slowing the infusion rate or permanently discontinuing treatment depends on severity.
• Posterior reversible encephalopathy syndrome (PRES): 2 cases have been reported. Permanent discontinuation is recommended if the clinical picture of PRES develops (headache, visual disturbances, seizures, altered mental status).
• Nausea/vomiting, fever, tachycardia, edema, peripheral neuropathy, and skin reactions (erythema multiforme, urticaria) are common.

The era of dinutuximab, naxitamab, and GD2-CAR-T

The landscape of anti-GD2 immunotherapy in 2026 encompasses four main approaches:

Naxitamab's distinctive position in this landscape is its suitability for outpatient administration. This is a major advantage for pediatric oncology centers serving international patients: rather than spending days in hospital, a Turkish or Kazakh child can attend a day-case chemotherapy–immunotherapy center for naxitamab treatment and return home. This significantly reduces both the burden on the family and psychological trauma.

Approximately 100-150 new neuroblastoma cases are diagnosed annually in Türkiye. About half fall into the high-risk category, meaning 50-75 patients each year. A substantial proportion are managed with standard induction + ASCT + retinoic acid; anti-GD2 immunotherapy is currently a component with limited use in Türkiye. To change this, the Ministry of Health needs to establish a specific reimbursement mechanism for anti-GD2 antibodies on the national pediatric oncology reimbursement list — one of the main requests on the Turkish pediatric oncology community's agenda in recent years.

The clinical journey of a Turkish child with high-risk neuroblastoma in 2026 typically proceeds as follows: diagnosis + INRG/INSS staging → induction chemotherapy (COG ANBL or SIOPEN modifications, 5-6 months) → surgical resection → ASCT (autologous, sometimes tandem) → radiotherapy (21,6 Gy to the primary tumor bed + stereotactic boost to selected metastatic sites) → retinoic acid maintenance (13-cis-retinoic acid, 6 months). Anti-GD2 immunotherapy is added during maintenance or at relapse depending on availability. For international patient centers such as Memorial Göztepe, this involves coordinating both the Turkish medical oncology board's decision and the reimbursement system of the patient's home country.

In 2020, the FDA granted naxitamab approval under the accelerated approval pathway . This is initial approval based on surrogate clinical endpoints such as ORR (overall response rate) and DOR (duration of response); to verify and further characterize clinical benefit, it was made conditional on completion of Study 201 . Study 201 planned a total of 80+ patients; PFS and OS endpoints would be evaluated during long-term follow-up.

As of the end of 2026, Study 201 data are still being actively collected. Preliminary results support approval, but the FDA's formal decision to “convert to full approval” has not yet been announced. The November 2025 NCCN guideline update, Y-mAbs' 2024 prescribing information revision, and the real-world experience of pediatric oncology centers worldwide show that the cumulative evidence has advanced significantly beyond the level at approval. Naxitamab now appears indisputably to be a lasting component of the treatment landscape for high-risk neuroblastoma.

This article is intended for medical news/information and does not provide individual treatment guidance. Naxitamab-gqgk (Danyelza) entered the market through the US FDA accelerated approval pathway on November 25, 2020, and confirmation of clinical benefit depends on Study 201 (NCT03363373) results. It does not yet have national authorization or SGK reimbursement in Türkiye; access is possible through individual importation or compassionate use. High-risk neuroblastoma treatment must be planned individually by a multidisciplinary pediatric oncology board (pediatric oncologist + pediatric surgeon + radiation oncologist + pediatric pathologist + pediatric radiologist). All numerical data in this article were compiled from the FDA approval document, the March 2024 revision of the Y-mAbs prescribing information, Mora et al.'s 2023 Cancers article, and the November 2025 NCCN Compendium update.