Y-mAbs Announces New Interim Analysis of Phase 2 Data for Naxitamab at 2024 ASCO Annual Meeting

NEW YORK, June 01, 2024 (GLOBE NEWSWIRE) — Y-mAbs Therapeutics, Inc. (the “Company” or “Y-mAbs”) (Nasdaq: YMAB), a commercial-stage biopharmaceutical company focused on the development and commercialization of novel radioimmunotherapy and antibody-based therapeutic products for the treatment of cancer, today announced new interim data from the Phase 2 Trial 201 of naxitamab in combination with granulocyte-macrophage colony-stimulating factor (“GM-CSF”) in patients with relapsed or refractory high-risk neuroblastoma with residual disease limited to bone and/or bone marrow. The results are summarized in poster presentations scheduled to be presented today, June 1, 2024, at the 2024 American Society of Clinical Oncology (“ASCO”) Annual Meeting in Chicago, IL.

Improved patient outcomes with extended naxitamab therapy: A poster titled “Patterns of improvement following initial response in patients treated with naxitamab for relapsed/refractory high-risk neuroblastoma” (poster #10033) demonstrates that continued treatment with naxitamab can further reduce disease following the initial response to naxitamab therapy. The Trial 201 prespecified interim analysis achieved a 50% overall response rate (“ORR”) in 26 out of 52 patients. Nearly a quarter of patients achieved their first complete response (“CR”) or partial response (“PR”) after three or more cycles of naxitamab therapy. Among these patients, most had initial stable disease within specific bone or bone marrow compartments prior to achieving a CR or PR. These results support the rationale for extended naxitamab therapy in patients who do not achieve a CR or PR at first assessment.

Evolution of adverse events over the course of treatment: A poster titled “Naxitamab-related adverse events within and across treatment cycles in patients with relapsed/refractory high-risk neuroblastoma” (poster #10032) demonstrates the frequency and patterns of adverse events (“AEs”) based on the interim analysis of Trial 201. In this analysis, 81% of naxitamab-related AEs were Grade 1 or 2, while Grade ≥3 AEs reported in ≥10% of patients included hypotension (60% of patients), pain (58%), urticaria (19%), bronchospasm (18%), and abdominal pain (16%). None resulted in treatment discontinuation. Notably, the frequency of naxitamab-related pain Grade 3 AEs decreased from the first cycle (53%) to the second (37%), generally stabilizing thereafter, with frequencies consistent across infusions. Similarly, the frequency of hypotension showed marked reductions across cycles and infusions.

“We are encouraged to see that some patients who did not demonstrate an objective response after initial assessment went on to achieve a complete or partial response after continued naxitamab treatment. In addition, these data provide a practical understanding of the temporal patterns of treatment-related adverse events,” said Vignesh Rajah, MBBS, DCH, MRCP (UK), Chief Medical Officer.

In addition, Dr. Jaume Mora and researchers from the Sant Joan de Déu Barcelona Children’s Hospital in Spain will present results from an independent retrospective analysis of patients treated with naxitamab in combination with chemotherapeutics in a poster titled “Naxitamab chemo-immunotherapy regimens other than with irinotecan/temozolomide for patients with relapsed/refractory high-risk neuroblastoma” (poster #10037). In this study, 29 patients with mostly chemo-immunotherapy refractory disease received compassionate use of naxitamab plus sargramostim in combination with alternative chemotherapeutics. Importantly, prior sensitivity to chemo-immunotherapy predicted better responses with the new combinations. The safety profiles of the alternative naxitamab chemo-immunotherapy regimens were considered manageable.

Y-mAbs will be available for comment at booth #35151 on the Exhibition Floor of McCormick Place.

Researchers at Memorial Sloan Kettering Cancer Center (“MSK”) developed DANYELZA® (naxitamab-gqgk), which is exclusively licensed by MSK to Y-mAbs. MSK has institutional financial interests in the compound and Y-mAbs.

About DANYELZA® (naxitamab-gqgk)
DANYELZA® (naxitamab-gqgk) is indicated, in combination with granulocyte-macrophage colony-stimulating factor (“GM-CSF”), for the treatment of pediatric patients 1 year of age and older and adult patients with relapsed or refractory high-risk neuroblastoma in the bone or bone marrow who have demonstrated a partial response, minor response, or stable disease to prior therapy. This indication was approved under accelerated approval based on overall response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefits in a confirmatory trial. DANYELZA® includes a Boxed Warning for serious infusion-related reactions, such as cardiac arrest and anaphylaxis, and neurotoxicity, such as severe neuropathic pain and transverse myelitis. See full Prescribing Information for complete Boxed Warning and other important safety information.

About Y-mAbs
Y-mAbs is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel, radioimmunotherapy and antibody-based therapeutic cancer products. The Company’s technologies include its investigational Self-Assembly DisAssembly (“SADA”) ​Pretargeted Radioimmunotherapy Platform (“PRIT”)​ and bispecific antibodies generated using the Y-BiClone platform. The Company’s broad and advanced product pipeline includes the anti-GD2 therapy DANYELZA® (naxitamab-gqgk), the first FDA-approved treatment for patients with relapsed or refractory high-risk neuroblastoma in the bone or bone marrow after a partial response, minor response, or stable disease to prior therapy.

Forward-Looking Statements
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Investor Contact:
Courtney Dugan
VP, Head of Investor Relations
cdu@ymabs.com