Cellectar Biosciences (NASDAQ:CLRB) shares soared 27% after the company received Rare Pediatric Disease Designation from the U.S. Food and Drug Administration (FDA) for its iopofosine I 131 therapy targeting relapsed or refractory pediatric high-grade glioma.
The designation highlights the potential of Cellectar’s radioconjugate monotherapy to address an aggressive and often fatal cancer affecting children and adolescents. The therapy had already received Orphan Drug Designation from the FDA.
If ultimately approved, the company may qualify for a Priority Review Voucher, which can either be used to expedite future regulatory reviews or sold to another firm. The Rare Pediatric Disease program aims to encourage the development of treatments for conditions primarily affecting patients under 18.
Interim findings from the ongoing CLOVER-2 Phase 1b study were promising. Patients receiving at least 55 mCi total administered dose achieved an average of 5.4 months of progression-free survival (PFS) and 8.6 months of overall survival (OS), compared to historical averages of 2.25 months PFS and 5.6 months OS.
Patients who underwent additional treatment cycles saw even better outcomes, with average PFS rising to 8.1 months and OS reaching 11.5 months. Two highlighted case studies showed marked tumor shrinkage and extended survival in heavily pre-treated patients.
“We believe iopofosine I 131 represents a compelling opportunity for strategic collaboration to accelerate development and bring a potentially first-in-class therapy to patients who urgently need new options,” said James Caruso, President and CEO of Cellectar.
The treatment was well tolerated, with a safety profile consistent with prior data—mainly manageable hematologic side effects and minimal off-target toxicity.