Cellectar Biosciences Presented Promising Preclinical Data in Poster Presentation at the American Association for Cancer Research (AACR) Special Conference on Pancreatic Cancer Research

Rhea-AI Summary

Cellectar Biosciences (NASDAQ: CLRB) presented preclinical data for CLR 225 at the AACR Special Conference on Pancreatic Cancer Research (Sept 28–Oct 1, 2025). The poster reported that CLR 225, an actinium-based alpha-emitter, completed IND-enabling studies and showed meaningful inhibition of tumor growth or reduced tumor volume across three pancreatic ductal adenocarcinoma xenograft models (PANC-1, MIA PaCa-2, BxPC-3).

The program demonstrated predictable, linear biodistribution, was well tolerated in dosing studies with no body-weight loss, and showed no toxicities in GLP toxicity studies; the company retains the option to advance to a Phase 1 first-in-human study.

Positive

• Tumor inhibition in three PDAC xenograft models (PANC-1, MIA PaCa-2, BxPC-3)
• Completed IND-enabling studies with option to advance to Phase 1
• GLP toxicity studies reported no toxicities observed
• Predictable biodistribution with dose linearity supporting dose estimation

Negative

• Efficacy and safety unproven in humans; only preclinical data reported
• No clinical trial start date or human dosing specified

Insights

Translational oncology analyst

Preclinical CLR 225 data show tumor inhibition, IND-enabling completion and safety signals; human studies remain required to confirm benefit.

The data describe meaningful inhibition or reduction of tumor volume across three pancreatic xenograft models and note a potential survival benefit after treatment. The program completed IND-enabling studies, reported predictable, dose-linear biodistribution, and stated no toxicities in multiple GLP toxicity studies; all findings support readiness to consider a Phase 1 first-in-human study.

These results reduce preclinical uncertainty because they combine efficacy signals, tolerability, and favorable pharmacokinetics in relevant models. Key dependencies remain explicit: a formal decision to advance into a Phase 1 trial and confirmation of safety and activity in humans. Watch for an actual Phase 1 initiation date, regulatory filings or IND acceptance, and early human safety/PK readouts over the next 6–18 months.

CLR 225 (225Ac-phospholipid ether) Demonstrates Meaningful Inhibition of Tumor Growth and Potential Survival Benefit In Three Pancreatic Cancer Xenograft Models

FLORHAM PARK, N.J., Oct. 14, 2025 (GLOBE NEWSWIRE) -- Cellectar Biosciences, Inc. (NASDAQ: CLRB), a late-stage clinical biopharmaceutical company focused on the discovery and development of drugs for the treatment of cancer, today announced that Jarrod Longcor, chief operating officer of Cellectar, presented positive preclinical data in a poster at the American Association for Cancer Research (AACR) Special Conference on Pancreatic Cancer Research that took place from September 28 through October 1, 2025, in Boston, Massachusetts. The poster highlighted preclinical data from CLR 121225 (CLR 225), the Company’s novel actinium-based radio conjugate alpha-emitter for treatment in pancreatic ductal adenocarcinoma (PDAC). CLR 225 has completed Investigational New Drug (IND)-enabling studies, and the company maintains the option to advance into a Phase 1 study.

“We were honored to present these preclinical data before a distinguished audience of oncology professionals. The novel mechanism of action of our phospholipid ethers may enable us to more effectively target and eradicate diverse tumor cell populations and, importantly, penetrate the dense, collagen-rich extracellular matrix that characterizes pancreatic cancer. By overcoming this major barrier to therapeutic delivery, we hope to address one of the fundamental reasons pancreatic tumors remain so refractory to standard treatments and ultimately improve patient outcomes,” said Jarrod Longcor, chief operating officer of Cellectar. “These results showcase the robust anti-tumor activity, selective biodistribution, and impressive uptake of CLR 225 in multiple pancreatic cancer tumor models. The data strongly support the therapeutic potential of CLR 225.”

A series of studies evaluated three separate pancreatic cancer xenograft models (PANC-1, MIA PaCa-2 human pancreatic carcinoma cells and BxPC-3 tumor fragments) treated with CLR 225 at multiple doses. CLR 225 was deemed safe and well-tolerated at all dosing levels with no changes in body weight or loss of animals. Notably, all three xenograft models treated with CLR 225 demonstrated either meaningful inhibition of tumor growth or reduction in tumor volume, depending on the dose, with potential survival benefit following treatment as tumor growth post treatment was significantly diminished.

Additional pharmacokinetic studies showed excellent biodistribution of CLR 225, indicating predictable behavior with dose linearity, which can assist with future estimation of a likely efficacious dose. Furthermore, in preparation for Phase 1 first-in-human studies, the poster presented data on CLR 225 in various GLP toxicity studies where no toxicities to the compound were noted.

The poster can be accessed on the Company’s website here.

About Pancreatic Ductal Adenocarcinoma
Advanced pancreatic ductal adenocarcinoma (PDAC) is a devastating disease, with less than 10% survival after five years. There are an estimated 67,500 new pancreatic cancer cases in the U.S. each year and PDAC accounts for approximately 90% of these cases, or ~60,700 new PDAC cases annually. Most patients are diagnosed at an advanced stage, which means that between 80%-90% of PDAC patients (~48,000-54,000 patients annually, per the Surveillance, Epidemiology, and End Results (SEER) database) are likely to have advanced disease at diagnosis.

PDACs exhibit a hypoxic environment, resulting in tumor cells employing lipid rafts to transport lipids into the cells. CLR 225 is designed to target lipid rafts and deliver treatment to the tumor cell.

About Cellectar Biosciences, Inc.
Cellectar Biosciences is a late-stage clinical radiopharmaceutical company focused on the discovery and development of proprietary drugs for the treatment of cancer. The company’s core objective is to leverage its proprietary Phospholipid Drug Conjugate™ (PDC) delivery platform to develop the next-generation of cancer cell-targeting treatments that deliver improved efficacy and better safety.

The company’s product pipeline includes its lead assets: iopofosine I 131, a PDC designed to provide targeted delivery of iodine-131 (radioisotope) for the treatment of hematologic and solid tumor cancers such as Waldenstrom’s macroglobulinemia (WM) and pediatric high grade gliomas; CLR 121125, an iodine-125 Auger-emitting program targeting solid tumors, such as triple negative breast, lung and colorectal cancers; CLR 121225, an actinium-225 based program targeting solid tumors with significant unmet need, such as pancreatic cancer; and proprietary preclinical PDC chemotherapeutic programs and multiple partnered PDC assets.

Iopofosine I 131 has been studied in Phase 2b trials for relapsed or refractory WM and multiple myeloma (MM), non-Hodgkin’s lymphomas and central nervous system (CNS) lymphoma, and the CLOVER-2 Phase 1b study, targeting pediatric patients with high-grade gliomas, for which Cellectar is eligible to receive a Pediatric Review Voucher from the FDA upon approval. The FDA has granted iopofosine I 131 Breakthrough Designation, six Orphan Drug, four Rare Pediatric Drug and two Fast Track Designations for various cancer indications. The European Medicines Agency (EMA) has also granted PRIME and orphan drug designations for the treatment of WM.

For more information, please visit www.cellectar.com or join the conversation by liking and following us on the company’s social media channels: X, LinkedIn, and Facebook.

Forward Looking Statements Disclaimer
This news release contains forward-looking statements. You can identify these statements by our use of words such as “may,” “expect,” “believe,” “anticipate,” “intend,” “could,” “estimate,” “continue,” “plans,” or their negatives or cognates. These statements are only estimates and predictions and are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made. These statements are based on our current beliefs and expectations as to such future outcomes. Drug discovery and development involve a high degree of risk. Factors that might cause such a material difference include, among others, uncertainties related to the FDA and EMA regulatory pathways, ability to execute strategic alternatives, identify suitable collaborators, partners, licensees or purchasers for our product candidates and, if we are able to do so, to enter into binding agreements with regard to any of the foregoing, or to raise additional capital to support our operations, or our ability to fund our operations if we are unsuccessful with any of the foregoing. A complete description of risks and uncertainties related to our business is contained in our periodic reports filed with the Securities and Exchange Commission including our Form 10-K for the year ended December 31, 2024, and our Form 10-Q for the quarterly period ending June 30, 2025. These forward-looking statements are made only as of the date hereof, and we disclaim any obligation to update any such forward-looking statements.

INVESTORS:
Anne Marie Fields
Precision AQ
212-362-1200
annemarie.fields@precisionaq.com

FAQ

What did Cellectar (CLRB) present at the AACR pancreatic cancer conference on Oct 2025?

Cellectar presented preclinical data showing CLR 225 inhibited tumor growth in three pancreatic xenograft models and completed IND-enabling studies.

Does CLR 225 (CLRB) have IND-enabling studies completed and can it enter Phase 1 in 2025?

Yes, CLR 225 completed IND-enabling studies and the company said it maintains the option to advance into a Phase 1 study.

What safety results did Cellectar report for CLR 225 (CLRB) in preclinical studies?

Preclinical dosing showed CLR 225 was well tolerated with no body-weight loss, and GLP toxicity studies reported no toxicities.

Which pancreatic cancer models showed responses to CLR 225 in Cellectar's poster?

Responses were reported in PANC-1, MIA PaCa-2 human carcinoma cells, and BxPC-3 tumor fragment xenograft models.

What biodistribution findings did Cellectar report for CLR 225 (CLRB)?

The poster reported excellent biodistribution with predictable behavior and dose linearity to aid future dose estimation.