Y-mAbs Therapeutics, Inc. a commercial-stage biopharmaceutical company focused on the development and commercialization of novel, antibody-based therapeutic products for the treatment of cancer, today announced that the U.S. Food and Drug Administration (“FDA”) has approved DANYELZA (naxitamab-gqgk) 40mg/10ml. DANYELZA 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 is approved under accelerated approval regulation based on the 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 is a humanized, monoclonal antibody that targets the ganglioside GD2, which is highly expressed in various neuroectoderm-derived tumors and sarcomas. DANYELZA is administered to patients three times a week in an outpatient setting and the treatment is repeated every four weeks. The product has received Priority Review, Orphan Drug, Breakthrough Therapy, and Rare Pediatric Disease designations from the FDA.

“Today is an important day for children living with refractory/relapsed high-risk neuroblastoma,” said Thomas Gad, founder, Chairman, and President. “It’s very exciting to see this treatment go from being an experimental therapy used at my daughter’s bedside to now being FDA approved. On behalf of Y-mAbs, I want to thank all the patients and physicians who took part in our clinical trials and our scientific partner, Memorial Sloan Kettering, for helping us achieve this goal.”

“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. This approval of Y-mAbs’ first BLA represents a key step in working towards our mission of becoming a world leader in developing better and safer antibody-based oncology products addressing unmet pediatric and adult medical needs,” said Claus Moller, Chief Executive Officer.

The FDA approval of DANYELZA is supported by clinical evidence from two pivotal studies in patients with high-risk neuroblastoma with refractory or relapsed disease. DANYELZA appears to be well tolerated with few discontinuations of treatment in the clinical trials and adverse events were clinically manageable. See below for information related to adverse reactions.

The FDA granted approval under the accelerated approval regulation. The postmarketing clinical trial required by the FDA to verify and to further characterize the clinical benefit is the ongoing Study 201, which will enroll a minimum of 80 patients and report overall response rate (“ORR”), duration of response (“DOR”), progression-free survival (“PFS”) and overall survival (“OS”). The ORR is the primary endpoint for the study, DOR is the secondary endpoint, PFS and OS are secondary endpoints in long-term follow-up.

DANYELZA is expected to be available in the United States in the coming weeks. To help patients get started on DANYELZA, Y-mAbs ConnectTM has been created to answer questions about access, health insurance coverage, financial support programs, and other resources available for qualifying patients. To learn more about Y-mAbs Connect, visit ymabsconnect.com.

Researchers at Memorial Sloan Kettering Cancer Center (“MSK”) developed DANYELZA, which is exclusively licensed by MSK to Y-mAbs. As a result of this licensing arrangement, MSK has institutional financial interests related to the compound and Y-mAbs.

About High-Risk Neuroblastoma

Neuroblastoma is a solid tumor of childhood that arises in the nervous system, outside of the brain. The clinical behavior of neuroblastoma is highly variable, with some tumors being easily treatable, but the majority being very aggressive. All patients are staged based on the International Neuroblastoma Staging System Committee (“INSS”) system, ranging from stage 1 through stage 4S.

All patients with stage 4 disease diagnosed after one year of age are classified in the high-risk category, where the neuroblastoma tumor cells have already metastasized to other sites in the body, such as the bone or bone marrow. Essentially all patients who have tumors with many copies, or amplification, of the MYCN oncogene also have high-risk disease, even if they do not have evidence of the tumor having spread.

Important Safety Information and Indication for DANYELZA® (naxitamab-gqgk)

Indication

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 is approved under accelerated approval based on the 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.

Contraindications

DANYELZA is contraindicated in patients with a history of severe hypersensitivity reaction to naxitamab-gqgk. Reactions have included anaphylaxis.

Warnings and Precautions

DANYELZA has been approved with a boxed warning.

In clinical studies, DANYELZA has been shown to cause serious infusion reactions including anaphylaxis, cardiac arrest, bronchospasm, stridor, and hypotension. Infusion reactions generally occurred within 24 hours of completing a DANYELZA infusion, most often within 30 minutes of initiation. Infusion reactions are most frequent during the first infusion in each cycle. Premedicate with an antihistamine, acetaminophen, an H2 antagonist, and corticosteroid as recommended in the label. Monitor patients closely for signs and symptoms of infusion reactions during and for at least 2 hours following completion of each DANYELZA infusion in a setting where cardiopulmonary resuscitation medication and equipment are available. Reduce the rate, interrupt infusion, or permanently discontinue DANYELZA based on severity and institute appropriate medical management as needed.

Based on its mechanism of action, DANYELZA can cause severe pain. Premedicate with gabapentin and e.g. oral oxycodone. Treat break-through pain with intravenous hydromorphone or equivalent.

One case of transverse myelitis (Grade 3) has been reported. Permanently discontinue DANYELZA therapy in case of transverse myelitis.

DANYELZA may cause severe hypertension. The onset of hypertension may be delayed. Monitor blood pressure during and after infusion. Interrupt DANYELZA infusion and resume at a reduced rate, or permanently discontinue DANYELZA based on the severity.

Two cases of posterior reversible encephalopathy syndrome (“PRES”) have been reported. Monitor blood pressure during and following DANYELZA infusion and assess for neurologic symptoms. Permanently discontinue DANYELZA in case of symptomatic PRES.

About Y-mAbs

Y-mAbs is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel, antibody-based therapeutic products for the treatment of cancer. The Company has a broad and advanced product pipeline, including DANYELZA and omburtamab, which target tumors that express B7-H3.