NEW YORK, NY, USA I July 12, 2022 I Y-mAbs Therapeutics, Inc. (the “Company” or “Y-mAbs”) (Nasdaq: YMAB) a commercial-stage biopharmaceutical company focused on the development and commercialization of novel, antibody-based therapeutic products for the treatment of cancer, today announced initiation of its first clinical trial with a SADA construct. This Phase 1 multicenter basket trial targets malignant melanoma, sarcoma and small cell lung cancer. The trial will have three parts: Part A with dose-finding for the SADA molecule and testing of dosing intervals between the protein and the 177Lu-DOTA payload, Part B will determine the optimal dose of 177Lu-DOTA, and Part C will be evaluating safety and initial signals of efficacy using repeated dosing. The Company expects a total of approximately 59 patients at 6-10 U.S. sites to be included in the trial.

The GD2-SADA construct was created using our SADA technology, which was licensed by the Company from Memorial Sloan Kettering Cancer Center (“MSK”) and Massachusetts Institute of Technology (“MIT”) in April 2020. The SADA technology utilizes a pre-targeted payload delivery method where antibody constructs assemble in tetramers and bind to the tumor target. Unbound constructs predictably disassemble into smaller antibody fragments and are excreted through the kidneys within hours after administration. In a second infusion, a radioactive payload binds to the antibody constructs attached to the tumor target in order to radiate the tumor. This provides the possibility of targeting tumors with precision while minimizing radiation of normal tissues. We believe that the SADA technology platform can deliver a variety of payloads and could potentially be developed against multiple tumor targets, as well as for theragnostic purposes.

“The FDA acceptance of the IND for GD2-SADA marks an important milestone towards our mission of developing novel SADA treatments as we continue to execute our clinical development strategy for our pipeline of SADA constructs for the treatment of cancers with unmet medical need,” said Thomas Gad, founder, President and Interim CEO. “We are seeing significant partnership interest for the SADA technology and we believe we are well-positioned to leverage the SADA platform as we move forward. We are truly excited about the potential of the SADA technology, which has already shown great promise, and we believe that it can further unlock the potential of radiolabeled therapeutics in tumors that have not historically demonstrated meaningful responses to radiolabeled agents.”

Researchers at MSK, including Dr. Cheung, developed the SADA technology for radioimmunotherapy, which is exclusively licensed by MSK to Y-mAbs.  Dr. Cheung has intellectual property rights and interests in the technology, and as a result of this licensing arrangement, MSK has institutional financial interests in the technology and in Y-mAbs.

About Y-mAbs

Y-mAbs is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel, antibody-based therapeutic cancer products. In addition to conventional antibodies, the Company’s technologies include bispecific antibodies generated using the Y-BiClone platform, and the SADA platform. The Company’s broad and advanced product pipeline includes one FDA-approved product, DANYELZA® (naxitamab-gqgk), which targets tumors that express GD2, and one product candidate at the registration-stage, OMBLASTYS® (omburtamab), which targets tumors that express B7-H3.