R&D Pipeline:

A Unique Approach to Cancer Treatment, Detection and Monitoring

Cellectar Biosciences is developing phospholipid drug conjugates (PDCs) designed to provide cancer targeted delivery of diverse oncologic payloads to a broad range of cancers and cancer stem cells. Cellectar’s PDC platform is based on the company’s proprietary phospholipid ether analogs. These novel small-molecules have demonstrated highly selective uptake and retention in a broad range of cancers. Cellectar’s PDC pipeline includes product candidates for cancer therapy and cancer diagnostic imaging.

PDC picture

The company’s lead therapeutic PDC, CLR 131, utilizes iodine-131, a cytotoxic radioisotope, as its payload. CLR 131 is currently being evaluated under an orphan drug designated Phase 1 study in patients with relapsed or refractory multiple myeloma. The company is also developing PDCs for targeted delivery of chemotherapeutics such as paclitaxel (CLR 1603-PTX), a preclinical stage product candidate, and plans to expand its PDC chemotherapeutic pipeline through both in-house and collaborative R&D efforts.

To learn more, please click on the following link:
Phospholipid Ether-Drug Conjugate (PDC) Platform for Targeted Delivery of Chemotherapeutics



Cellectar Biosciences R&D Pipeline

PDC Product Development Pipeline

  • Chemotherapeutics:

    • CLR 1603-CTX – Undisclosed
    • CLR CTX (PTX, GEM, GEL1) – Collaboration with Pierre Fabre

* The development of CLR 125 is fully funded by a NCI Phase I/II Fast-Track SBIR research grant award

1PTX = Paclitaxel; GEM = Gemcitabine; GEL = Geldanamycin





CLR 131
CLR 131 is a small-molecule, broad-spectrum, cancer-targeting radiotherapeutic PDC that is designed to deliver cytotoxic (cell-killing) radiation directly and selectively to cancer cells and cancer stem cells. CLR 131 is our lead PDC radiotherapeutic product candidate and is currently being evaluated in a Phase 1 study for the treatment of relapse or refractory multiple myeloma. Multiple myeloma is an incurable cancer of plasma cells. This cancer type was selected for both clinical and commercial rationales, including multiple myeloma’s highly radiosensitive nature, continued unmet medical need in the relapse/refractory setting and the receipt of an orphan drug designation. The Investigational New Drug (IND) application was accepted by the U.S. Food and Drug Administration (FDA) in March 2014. In December 2014, the FDA granted orphan drug designation for CLR 131 for the treatment of multiple myeloma. The Phase 1 study was initiated in April 2015 and we anticipate evaluating our first cohort and initiating the second cohort in January 2016. The primary goals of the Phase 1 study are to assess the compound’s safety, identify a Phase 2 dose, and possibly obtain an early evaluation of low dose activity.

To learn more, please click on the following link:
Positive Data From Phase 1 Therapeutic Trial of CLR 131 in Multiple Myeloma

CLR 125

CLR 125 is a broad-spectrum, cancer-targeting, radiotherapeutic currently under pre-clinical investigation for the treatment of micrometastatic disease. Similar to CLR 131, the selective uptake and retention of CLR 125 has been observed in malignant tissues during pre-clinical studies. CLR 125 uses the radioisotope Iodine-125 (which has a 60-day half-life), which may provide an excellent tumor kinetics match with Cellectar’s proprietary delivery vehicle. Pre-clinical research will include: chemistry, manufacturing and controls of CLR 125; biodistribution and toxicity studies of CLR 125 in pre-clinical models; and efficacy and dose-response studies.

To learn more, please click on the following link:

Cellectar Biosciences Awarded $2.3M National Cancer Institute Fast-Track SBIR Grant to Advance Phospholipid Drug Conjugate (PDC) Delivery Platform





The Company is exploring the creation of additional PDCs ranging from newly discovered to well-characterized chemotherapeutic payloads under its CLR CTX Chemotherapeutic PDC program. The objective of our CTX program is to develop PDC chemotherapeutics through conjugation of our delivery vehicle and non-targeted anti-cancer agents to improve therapeutic indices and expand potential indications through the targeted delivery of chemotherapeutic payloads. Initial CTX product candidates include CLR 1601-PTX and CLR 1603-PTX; both are small-molecule, broad-spectrum, cancer-targeting chemotherapeutics in pre-clinical research. These PDCs are designed to selectively deliver paclitaxel, a chemotherapeutic payload to cancer cells and cancer stem cells increasing the therapeutic index of paclitaxel as a monotherapy. Both of our paclitaxel PDC’s are being evaluated in vitro and in vivo to demonstrate formulation stability and PDC cancer targeting selectivity.

Recently, we have cultivated a research collaboration opportunity with Pierre Fabre, the third largest French pharmaceutical company, designed to combine Cellectar’s proprietary PDC delivery platform with a selection of Pierre Fabre’s proprietary cytotoxics. These new Small-Molecule-Drug-Conjugate products (SMDCs) are designed to exhibit high selectivity towards cancer cells in order to expand therapeutic index and provide improved clinical performance to otherwise highly potent agents.

The primary objective of the research collaboration is to co-design a library of constructs and to achieve in-vivo Proof-of-Concept of the superiority of these PDCs to the corresponding naked payloads. Thanks to their remarkable lipid rafts-mediated distribution properties, PDCs are expected to provide enhanced therapeutic indices to otherwise highly potent payloads through targeted delivery to cancer cells.

Pierre Fabre will provide the payloads and its know-how in the design of natural product-derived active conjugates, as well as its prior expertise into SMDCs.

Cellectar will provide its proprietary PDC Platform technology and will be in charge of conducting the drug discovery program up to preclinical stage and, should it be successful, to clinical evaluation.

Pierre Fabre has been granted the option to license any, or all, of the new drug conjugates developed as part of the research collaboration, while Cellectar will own all intellectual property (IP) associated with the new drug conjugates.

To learn more, please click on the following links:
Pierre Fabre Collaboration

Phospholipid Drug Conjugate (PDC) Platform Development Update

Cellectar Biosciences Converts Patent Application for Phospholipid-Ether Analogs as Cancer Targeting Drug Vehicles




Diagnostic Imaging

CLR 124

CLR 124 is a small-molecule, broad-spectrum, cancer-targeting positron emission tomography (PET) imaging PDC that we believe has the potential to be the first of its kind for the selective detection of tumors and metastases in a broad range of cancers. CLR 124 has been used for PET/CT imaging in a broad array of tumor types through Company and investigator-sponsored clinical trials. We are in the process of evaluating the data from those studies. In April 2014, the FDA granted CLR 124 orphan status as a diagnostic for the management of glioma.

CLR 1502

CLR 1502 is a small-molecule, broad-spectrum, cancer-targeting NIR-fluorophore optical imaging PDC for intraoperative tumor and tumor margin illumination. This past June, after review of the Company’s IND application, the FDA determined that CLR 1502 will be evaluated as a combination product and assigned to the Center for Devices and Radiological Health (CDRH). As a result of this classification, the FDA has advised Cellectar that it will need to submit a new investigational application for the combination product prior to initiating its Phase 1 study in breast cancer surgery. As a result, Cellectar is identifying the optimal clinical development pathway. Based on our assessment, the Company believes that product will be similarly treated by third-party payors and end users post marketing approval regardless of regulatory pathway.

To learn more, please click on the following link:
Chief Scientific Officer Receives International Recognition for Pioneering Research

Peer-Reviewed Glioma Surgery Study With Cellectar Biosciences Fluorescence Cancer-Targeting Agents Chosen for the Cover of Neurosurgery

We believe our PDC platform has potential to provide targeted delivery of a diverse range of oncologic payloads, as exemplified by the product candidates listed above, that may result in improvements upon current standard of care (SOC) for the treatment and diagnostic imaging of a broad range of human cancers.


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