Cellectar expands IP estate and raises up to $140 million for iopofosine I 131

Cellectar Biosciences announced a broad expansion of its global intellectual property estate and an oversubscribed financing of up to $140 million. The financing supports a confirmatory study and NDA filing for accelerated approval of iopofosine I 131 in Waldenström macroglobulinemia with the FDA, while the company is advancing a planned 3Q26 filing for conditional marketing approval with the European Medicines Agency.

The company said it entered into a securities purchase agreement with certain institutional investors, and an additional securities purchase agreement with certain members of management, to issue and sell up to an aggregate of approximately $35 million upfront and $105 million in milestone-based securities in a registered direct offering of common stock and a concurrent private placement of common stock, pre-funded warrants, and milestone-based warrants. The oversubscribed financing was led by Nantahala Capital Management, with participation from healthcare-focused investors and members of the executive management team.

In connection with the transaction, Andrew Gu of Nantahala Capital Management, LLC will join Cellectar’s Board of Directors upon closing. Certain members of the executive management team agreed to participate in the financing at a purchase price of $2.88 per share of Common Stock and accompanying milestone-based Tranche A, Tranche B and Tranche C Warrants with an exercise price of $2.88 per share.

Cellectar said the expanded IP coverage includes newly issued patents across Europe, Asia-Pacific, the Middle East, and the Americas. The additions strengthen protection around iopofosine I 131 and the broader portfolio, including CLR 125, the company’s Auger-emitting radiopharmaceutical in development as a treatment for triple negative breast cancer.

The expanded IP coverage spans multiple patent families critical to the company’s therapeutic and platform strategies:

• Ether and Alkyl Phospholipid Compounds for Treating Cancer and Imaging Cancer Stem Cells, covering iopofosine I 131 and CLR-125 for both therapeutic use and imaging/detection of primary tumors and cancer stem cells, newly issued in Europe, China, Israel, Eurasia, and New Zealand.
• Fractionated Dosing of a Phospholipid Ether Analog for the Treatment of Cancer, covering proprietary iopofosine I 131 dosing regimens, newly issued in Eurasia, Israel, Turkey, Mexico, and Canada.

The company said it is following guidance from the EMA’s Scientific Advice Working Party and is advancing its planned filing for conditional marketing authorization of iopofosine I 131 for Waldenström macroglobulinemia in Europe. It also said the financing supports plans to initiate a global confirmatory study in the fourth quarter of 2026.

Cellectar said iopofosine I 131 has been studied in Phase 2b trials for relapsed or refractory multiple myeloma and central nervous system lymphoma, and that the FDA has granted the candidate Breakthrough, six Orphan Drug, four Rare Pediatric Drug and two Fast Track Designations for various cancer indications, while the EMA has granted iopofosine I 131 PRIME. The company said CLR 125 is currently being evaluated in a Phase 1b study for triple negative breast cancer, and CLR 225 is being targeted to several solid tumors with significant unmet need.