Y-mAbs Therapeutics (YMAB) Status Update summary

Strategic Vision and Platform Development

• Established two business units to maximize Danyelza’s potential and accelerate radiopharmaceutical platform growth, focusing on SOTTA-PRIT/SADA technology and five strategic enablers addressing radiopharma gaps such as off-target toxicity and theranostic capabilities.

• Emphasized a pre-targeted approach where protein and radioisotope assembly occurs in the patient, reducing manufacturing costs and enabling modular, patient-specific treatments.

• Business realigned into DANYELZA and Radiopharmaceuticals units, with new executive leadership and increased organizational focus.

• Investment strategy prioritizes development over capital expenditures, emphasizing physician participation throughout the treatment journey.

• SADA PRIT platform validated in humans, positioned to disrupt the radiopharmaceutical industry and improve patient outcomes.

Clinical Trial Progress and Safety Findings

• Phase 1 Trial 1001 Part A for GD2-SADA-177Lu-DOTA met its primary safety endpoint, demonstrating safety and tolerability with no dose-limiting toxicities or treatment-related serious adverse events; most adverse events were mild to moderate.

• Pharmacokinetics of GD2 SOTTA/SADA and Luzoda were predictable and dose-dependent, supporting tailored clearance intervals and precise dosing.

• 22 patients enrolled; 9 showed positive tumor uptake and were eligible for the treatment stage.

• No pain historically associated with anti-GD2 therapies was observed.

• Higher concentrations of 177Lu-DOTA correlated with higher GD2-SADA protein, indicating effective targeting.

Dosimetry and Tumor Uptake Insights

• Expanded SPECT/CT analysis showed 16 of 22 patients had tumor uptake, with increased absorbed dose per tumor compared to protocol-restricted analysis.

• Protocol limitations excluded some tumors with uptake from evaluation; future trials will use central review and advanced imaging to assess all lesions.

• Dosimetry indicated the optimal therapeutic index was not reached, informing future study design and molecule optimization.