$Cellectar Biosciences Inc.(CLRB)$
StreetInsider

Cellectar Biosciences (CLRB) Announces Positive Prelim. Results for CLR 1602 in Tumor Targeting

June 15, 2016 8:34 AM
Cellectar Biosciences, Inc. (Nasdaq: CLRB) announces the results of a preliminary tumor-targeting study that shows its prototype paclitaxel chemotherapeutic conjugate, CLR 1602, may be up to 30 times more tumor selective in comparison to free paclitaxel.

The preliminary in vivo study demonstrated that tumor uptake of CLR 1602’s paclitaxel payload increased by more than 30-fold over free paclitaxel, and also displayed an extended plasma half-life relative to free paclitaxel. The extended plasma half-life may, in part, explain the enhanced tumor uptake. Unlike free paclitaxel, which was rapidly cleared from plasma within 24 hours, CLR 1602 displayed prolonged retention even at 96 hours.

“The study results are a significant signal in the development of our paclitaxel Phospholipid Drug Conjugates (PDCs). More importantly, it represents further validation of our entire CLR CTX program,” said Jim Caruso, president and CEO of Cellectar Biosciences. “These data clearly confirm our ongoing assertion that delivery of chemotherapeutics with our PDC platform may provide superior tumor cell targeting than chemotherapeutics alone, converting non-targeted chemotherapeutics into targeted cytotoxic agents. We anticipate conducting **re studies and evaluating against other comparators, such as Abraxane™.”

The study was designed to assess the pharmacokinetics, absorption, and distribution after a single intravenous administration of CLR 1602, (N=24) a paclitaxel PDC vs. free paclitaxel (N=24) in tumor bearing mice. In this biodistribution study, CLR 1602, a paclitaxel Cremophor EL-free formulation (formulated without Cremophor, which is believed to contribute to free paclitaxel adverse event profile), was compared to free paclitaxel at equivalent sub-therapeutic concentrations in an effort to demonstrate enhanced CLR 1602 tumor targeting vs. free paclitaxel.

“This promising new in vivo paclitaxel data further confirms the tumor targeting selectivity of our PDC carrier, which has been consistently observed with oncology therapeutics and imaging agents. With targeting confirmed we will now optimize the PDC linker with the aim of enhancing the cytotoxic impact on cancer cells,” said Jamey Weichert, Ph.D., founder and chief scientific officer of Cellectar Biosciences. “Furthermore, these results validate our ‘tool kit’ concept whereby carbon-14 labeled versions of our PDCs are utilized to quickly assess the potential tumor targeting enhancement that our PDC delivery system may afford to existing or new chemotherapeutic agents.”

These quantitative results comparing biodistribution of CLR 1602 vs. free paclitaxel will be the subject of a poster presented at the 35th National Medicinal Chemistry Symposium in Chicago, June 26-29. The company also anticipates further data to be presented at another conference later this year.