On November 25, 2020, the FDA granted accelerated approval to naxitamab-gqgk (Danyelza; Y-mAbs Therapeutics), a GD2-binding monoclonal antibody, in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) for the treatment of relapsed or refractory high-risk neuroblastoma in the bone or bone marrow in pediatric patients aged ≥1 year and adults who achieved a partial response, minor response, or stable disease after receiving previous therapy. The FDA granted naxitamab priority review and breakthrough therapy, orphan drug, and rare pediatric disease designations.
“We believe that Danyelza in combination with GM-CSF is a much-needed treatment for patients with relapsed/refractory high-risk neuroblastoma in the bone or bone marrow who have historically not had approved treatments available,” said Claus Moller, Chief Executive Officer, Y-mAbs Therapeutics.
The approval of naxitamab was based on the results of 2 single-arm, open-label clinical trials in patients with relapsed or refractory neuroblastoma in the bone or bone marrow. The patients received naxitamab 3 mg/kg via intravenous infusion on days 1, 3, and 5 of each 4-week cycle in combination with GM-CSF subcutaneously at 250 µg/m2 daily on days –4 to 0 and at 500 µg/m2/day on days 1 to 5. The cycles were repeated every 4 to 8 weeks. At the investigator’s discretion, the patients received preplanned radiation to the main disease site in Study 201 and radiation therapy to nontargeted bony lesions or soft-tissue disease in Study 12-230.
The primary end points were overall response rate (ORR) per the revised International Neuroblastoma Response Criteria, and the duration of response (DOR). The ORR in Study 201 (N = 22) was 45% (95% confidence interval [CI], 24%-68%), and 30% of responders had a DOR of ≥6 months. In Study 12-230 (N = 38), the ORR was 34% (95% CI, 20%-51%), with a DOR of ≥6 months in 23% of responders. The responses were in the bone, the bone marrow, or in both.
The most common (≥25%) adverse reactions with naxitamab were infusion-related reactions, pain, tachycardia, vomiting, cough, nausea, diarrhea, decreased appetite, hypertension, fatigue, erythema multiforme, peripheral neuropathy, urticaria, pyrexia, headache, injection-site reaction, edema, anxiety, localized edema, and irritability.
Grade 3 or 4 adverse events (≥5%) were decreased levels of lymphocyte count, neutrophil count, hemoglobin, platelet count, potassium, glucose, calcium, albumin, sodium, and phosphate; and increased alanine aminotransferase.