Cellectar Biosciences says Iopofosine I 131 well tolerated in case studies

Cellectar Biosciences (CLRB) announced that Jarrod Longcor, COO of Cellectar, delivered an oral presentation followed by a 55-minute panel discussion with other experts in the field at the American Association for Cancer Research Special Conference on Pediatric Cancer that took place September 25-28 in Boston, Massachusetts. The oral presentation highlighted interim data from the Phase 1b dose and regimen optimization study of iopofosine I 131 in inoperable relapsed or refractory pediatric high-grade glioma. Iopofosine I 131 is a potential first-in-class, novel cancer targeting agent utilizing a phospholipid ether as a radioconjugate monotherapy. The U.S. FDA previously granted Rare Pediatric Drug and Orphan Drug Designations for iopofosine I 131 for the treatment of pHGG. The interim data were delivered by Mr. Longcor in an oral presentation titled, “Precision Radiotherapy for Incurable Brain Tumors: Phase 1b Dose & Regimen Optimization Study of Iopofosine I 131 in Inoperable Relapsed or Refractory Pediatric High-Grade Glioma, Interim Data Assessment.” All patients receiving a minimum of 55 mCi total administered dose and evaluable experienced an average of 5.4 months of PFS and 8.6 months of OS, ongoing. All patients experienced disease control, which according to the committee for the Response Assessment in Pediatric Neuro-Oncology does correlate with survival benefit. Three patients who received additional dosing cycles, ongoing, with two achieving an objective response. Two case studies were highlighted in the oral presentation. Case Study 1 showed a 25-year-old male with diffuse hemispheric glioma with the H3 G34R/V mutation who had three prior therapies and who received a total administered dose of 126.6mCi of iopofosine I 131 over four doses had his target lesion reduced by more than 50% approximately eight months post screening. This patient had PFS of 10.9 months and survival is ongoing at greater than 18 months as of July 25, 2025. Case Study 2 showed a 15-year-old female with ependymoma who had eight prior therapies and who received a total administered dose of 58.9mCi of iopofosine I 131 over four doses had her target lesion reduced from 252mm2 to approximately 141mm2. This patient had PFS of 11.2 months and her ongoing survival was greater than 17 months as of July 22, 2025. Iopofosine I 131 was well tolerated and its toxicity profile was consistent with the company’s previously reported safety data. Importantly, patients in the study treated with iopofosine I 131 did not experience any cardiovascular, renal, or liver toxicities, peripheral neuropathy or significant bleeding. The safety profile was consistent with selective targeting of tumor sites with clinically negligible off-target effect outside the hematologic system. The most frequently reported treatment-emergent adverse events were hematologic in nature and were predictable and manageable. No treatment-related deaths were reported.