Cellectar Biosciences Secures $140 Million Financing to Advance Iopofosine I 131 Toward FDA Accelerated Approval in Rare Lymphoma

Cellectar Biosciences has closed financing of up to $140 million to fund a Phase 3 confirmatory study of iopofosine I 131 in relapsed/refractory Waldenström Macroglobulinemia (r/r WM) and a subsequent FDA accelerated approval submission, a sequencing that places confirmatory study design and endpoint alignment squarely on the critical path for QA and regulatory teams.

The financing follows 12-month follow-up data from the Phase 2b CLOVER WaM study (n=55), which met both primary and secondary endpoints. The protocol population achieved a major response rate (MRR) of 61.8% and a median duration of response of 17.8 months. Supporting data included an overall response rate of 83.6%, median progression-free survival of 13.5 months, and a disease control rate of 98.2%. Cellectar states the 12-month follow-up horizon was set in alignment with FDA expectations, a detail that will inform how the confirmatory protocol is structured and reviewed.

For regulatory affairs leads, the accelerated approval pathway in a rare oncology indication carries well-documented post-marketing obligations. The confirmatory study must be underway, and its design defensible, at the time of submission. Cellectar's stated plan to initiate the Phase 3 study before filing compresses the timeline but reduces the post-approval commitment risk that has drawn agency scrutiny in recent oncology programs.

In parallel, Cellectar dosed the first patients in a Phase 1b dose-finding study of CLR 125, a radio-conjugate candidate targeting triple-negative breast cancer. Early dosimetry, safety, and efficacy data are expected mid-year 2026. The program expands the company's Phospholipid Drug Conjugate (PDC) platform beyond hematologic malignancies into solid tumors, where radiopharmaceutical dosimetry and organ-at-risk assessments add complexity to both manufacturing and clinical site qualification.

Efficacy data from a subset of r/r WM patients treated with iopofosine I 131 immediately following BTK inhibitor therapy has been selected for poster presentation at the American Society of Clinical Oncology (ASCO) Annual Meeting, May 29 through June 2, 2026, a venue that will give the dataset its first broad peer exposure ahead of any regulatory filing.

The confirmatory study initiation timeline, and the FDA's acceptance of the accelerated approval package, will serve as the next measurable checkpoints against which Cellectar's regulatory strategy can be assessed.

Source: Cellectar Biosciences, Inc. via GlobeNewswire, May 14, 2026. Company webcast and conference call held at 8:30 AM ET on the same date.