Abstract A004: Efficacy of naxitamab in relapsed high-risk neuroblastoma
Jaume Mora, Godfrey C. Chan, Daniel A. Morgenstern, Loredana Amoroso, Karsten Nysom, Joerg Faber, Arthur Wingerter, Alba Rubio-San-Simon, Blanca Martinez de Las Heras, Sharif X. Koep, Maria During, Brian H. KushnerAbstract
Background and Aims:
High-risk neuroblastoma (HR-NB) has a poor prognosis when there is residual disease in bone or bone marrow (BM) following relapse treatment. Naxitamab is a humanized GD2-binding monoclonal antibody administered with granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with refractory/relapsed (R/R) HR-NB in bone and/or BM. We report pre-specified interim analysis of Trial 201 in patients with relapsed disease (data cut-off 31-Dec-2021).
Methods:
Ongoing Trial 201 (phase II, NCT03363373) evaluates naxitamab + GM-CSF in patients with R/R HR-NB with residual disease in bone/BM. Patients with soft tissue or actively progressing disease were ineligible. Naxitamab was infused at 3mg/kg/dose (∼90mg/m2/dose) intravenously on Days 1, 3, and 5 with GM-CSF administered subcutaneously on Days -4 to 5 (monthly cycles). Response was evaluated by independent review using INRC (2017) criteria.
Results:
Twenty-six patients enrolled in the primary efficacy analysis set with relapsed disease, including 12 with prior anti-GD2 therapy. The overall response rate (complete response (CR) + partial response (PR)) was 42% [95%CI:23-63%] with 31% CR. Median number of cycles to first response was 2 (range:2-8) and to CR was 2 (range:2-7). Median duration of response was 25 weeks [95%CI:0.9-not estimable (NE)]. Responses by disease compartment were 46% [95%CI:26-67%] (CR=29%) in relapsed bone disease (n=24) and 55% [95%CI:23-83%] in relapsed BM disease (n=11). Among the 12 patients with relapsed disease and prior anti-GD2 therapy, the response rate was 33% [95%CI:10-65%-], with 25% CR, and the disease control rate (CR + PR + minor response (MR) + stable disease (SD)) was 67% [95%CI:35-90%]. Three relapsed patients received anti-GD2 therapy as part of their recent salvage treatment regimens prior to 201 enrollment, two of whom responded. The median change in Curie Score among relapsed patients with prior GD2 exposure was -1 (range: -7 to 14). Median Kaplan-Meier progression-free survival estimates for patients without and with prior GD2 exposure were 30 weeks [95%CI:9.3-NE] and 25 weeks [95%CI:5.6-30.6], respectively. The frequency of Grade 3+ and serious related adverse events was higher for patients with relapsed vs primary refractory disease, including severe hypotension (68% vs. 51%), increased ALT (14% vs. 0%), and hypoxia (16% vs. 3%).
Conclusion:
These findings support naxitamab + GM-CSF as an active treatment approach for patients with relapsed HR-NB and residual disease in bone and/or BM, including patients previously exposed to anti-GD2 therapy.
Acknowledgements:
This study was funded by SERB Pharmaceuticals.
Citation Format:
Jaume Mora, Godfrey C. Chan, Daniel A. Morgenstern, Loredana Amoroso, Karsten Nysom, Joerg Faber, Arthur Wingerter, Alba Rubio-San-Simon, Blanca Martinez de Las Heras, Sharif X. Koep, Maria During, Brian H. Kushner. Efficacy of naxitamab in relapsed high-risk neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Bridging Discovery and Clinical Impact in Pediatric Cancer; 2026 Sep 22-25; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(18_Suppl_1):Abstract nr A004.