Dose Escalation Study of CLR 131 in Pediatric Relapsed/Refractory Malignant Tumors Including Neuroblastoma and Sarcomas

Even with standard, highly toxic multimodality therapies and salvage regimen, most pediatric patients with primary metastatic or relapsed solid tumors are confronted with a poor prognosis. For these patients there is currently no accepted successful treatment regimen. There is a need for new drugs, including targeted radiopharmaceuticals, preferably with cancer-specific uptake and broad applicability for these rare pediatric malignancies.

CLR 131 is a radioiodinated therapeutic that exploits the selective uptake and retention of phospholipid ethers (PLEs) by malignant cells. Cellectar Biosciences' novel cancer-targeted small-molecule compound (CLR1404) is radiolabeled with the isotope iodine-131 (I-131). CLR 131 has demonstrated tumor selective uptake across numerous adult and pediatric cancer cell types. Therapeutic efficacy has been demonstrated in various pediatric and adult-type cancer xenograft models, confirming the ability of CLR 131 to target tumors.

Based on the critical unmet medical need for effective agents with novel mechanisms of action in relapsed pediatric cancers and initial preclinical and clinical experience with radioiodinated CLR1404, Cellectar Biosciences has chosen to assess CLR 131 in a phase 1 pediatric trial.