FLORHAM PARK, New Jersey, May 5, 2026, 16:03 EDT
Cellectar Biosciences on Tuesday secured up to $140 million in new funding and rolled out fresh 12-month results for its iopofosine I 131 program, giving the cancer drug maker a shot of cash for a planned confirmatory trial and a potential U.S. submission in Waldenström macroglobulinemia. The company pegged the overall response rate at 83.6% from its Phase 2b CLOVER WaM trial, targeting this rare blood cancer.
Timing is key here. In its most recent annual report, Cellectar disclosed $13.2 million in cash on hand as of the close of 2025, cautioning that, unless it secures additional liquidity, routine operations may only be funded through Q3 2026. The filing also cast significant doubt over the company’s ability to stay afloat as a going concern.
The securities package breaks down to roughly $35 million delivered immediately, plus another $105 million tied to hitting specific milestones. Cellectar said it plans to use the capital to fund a randomized confirmatory trial and prepare a New Drug Application—the company’s formal bid for FDA marketing clearance—targeting accelerated approval for iopofosine I 131.
Cellectar said it now has at least a year of follow-up data for every patient in the study, fulfilling what it described as an FDA request. Among the 55 patients analyzed per protocol, the company posted a 61.8% major response rate—the higher standard for clinical benefit—along with a median response duration of 17.8 months. Median progression-free survival landed at 13.5 months.
Jarrod Longcor, Cellectar’s chief operating officer, pointed to “depth, durability, and consistency of responses” as backing iopofosine’s promise in WM. “Durability of response continues to improve over time,” Chief Executive James Caruso added, noting Cellectar is aiming to kick off the confirmatory study in the fourth quarter. GlobeNewswire
Nantahala Capital took the lead in the financing, joined by Balyasny Asset Management, Caligan Partners, Janus Henderson Investors, SilverArc Capital Management, Stonepine Capital Management, StemPoint Capital, Empery Asset Management and several other healthcare-focused funds. Caruso pointed to “strong demand for this financing.” Nantahala’s Andrew Gu — slated for a board seat post-closing — pointed to Cellectar’s “meaningful body of clinical evidence” in the disease. Cellectar Biosciences, Inc.
It was a lopsided session for Cellectar. According to Public.com, shares kicked off at $4.55, swinging between $3.11 and $4.70 on an eye-popping 53.78 million shares—blowing past the normal 34,900 average. Market cap? Approximately $12 million, by those same figures.
Cellectar is looking to break into a field currently dominated by Bruton tyrosine kinase inhibitors—BTK inhibitors—which are oral drugs that interrupt cancer signaling in certain blood cancers. The FDA cleared zanubrutinib, branded as Brukinsa, for adult WM back in 2021. Meanwhile, the agency’s orphan-drug database shows that ibrutinib, marketed as Imbruvica, got the green light for WM in 2015.
The company is targeting patients who’ve already been exposed to BTK inhibitors—an area with limited remaining options. According to Cellectar, iopofosine delivered a 64.1% major response among these BTK inhibitor-exposed cases, and a 63.6% rate for those considered refractory—meaning their cancer had resisted the entire drug class.
Jonathan Aschoff at Roth Capital trimmed his price target on Cellectar to $11, down from $14, though he’s sticking with a Buy, TipRanks/The Fly reported. Aschoff pointed to the 12-month data, saying it backs up the case for an accelerated approval filing before Phase 3 kicks off in the fourth quarter.
The deal doesn’t come with straightforward capital. Upfront, investors get common stock and pre-funded warrants on roughly 13.2 million shares—over triple the 4.24 million shares Cellectar listed as outstanding back on April 29. There’s also the potential for even more dilution: three additional milestone warrant tranches are on the table, pending approval and triggers.
Regulatory risk isn’t going anywhere. The FDA’s accelerated approval gives the green light to drugs for serious conditions if there’s a marker likely to signal benefit—but drugmakers still have to deliver confirmatory studies. If those trials flop, the agency warns, a drug can be yanked. Cellectar, in its own filing, acknowledges there’s no guarantee any candidate will win approval or turn a profit.
That next key readout is just ahead. Cellectar announced that data on iopofosine for relapsed or refractory WM patients—specifically those treated right after BTK inhibitor therapy—will be featured at the American Society of Clinical Oncology annual meeting, running May 29 to June 2 in Chicago.
