Rexahn Pharmaceuticals, Inc. a clinical stage biopharmaceutical company developing best-in-class therapeutics for the treatment of cancer, today announced promising preclinical results for RX-21101, the Company’s first development candidate derived from its Nano-Polymer-Drug Conjugate System (NPDCS) platform.
Results of the study were presented in a poster titled, “Synthesis of targeted docetaxel-polymer conjugate and its anti-tumor efficacy,” at the American Association for Cancer Research (AACR) Annual Meeting 2014 held earlier this month.
The preclinical study was conducted by Rexahn in collaboration with the University of Maryland and Ohio State University, and evaluated the effect of RX-21101 in both in vitro human cancer cell lines and in vivo mice xenograft tumor models using human cancer cell lines. Results of the preclinical studies were the following:
- RX-21101 showed complete tumor growth inhibition, enhanced tumor regression, and extended survival in mouse xenograft models without significant changes in body weight compared to intravenously administered docetaxel
- The maximum tolerated dose of RX-21101 in mice was more than 150 mg/kg, which is much higher than that of free docetaxel (~25 mg/kg)
- RX-21101 inhibited the proliferation of a variety of human cancer cells in the in vitro study
- The high water solubility of RX-21101 eliminates the need of toxic co-solvents that are used with systemically administered docetaxel
- This study demonstrated that RX-21101 is a promising anti-tumor development candidate with reduced toxicity and prolonged survival
“We are very encouraged by these preclinical findings, which showed that RX-21101 can inhibit tumor growth, increase tumor regression, and decrease the toxicity normally associated with a chemotherapeutic drug. Drug candidates developed on the NPDCS platform represent a clinical development approach for Rexahn with low risk, as we work to improve upon FDA approved anticancer compounds that are already widely used. We believe that our NPDCS platform could offer opportunities to co-develop and introduce new and improved versions of chemotherapeutic drugs that currently are, or are soon to become generic,” commented Rexahn’s CEO, Peter D. Suzdak, Ph.D.
Rexahn’s NPDCS platform combines existing chemotherapeutic agents with a proprietary polymer carrier that contains a targeting moiety which directs the drug directly into the tumor. This approach minimizes the levels of freely circulating anti-cancer agents in the body, which can reduce potential adverse events, and maximizes anti-tumor activities by accumulating the drug in the cancer tumor. NPDCS is a broad platform that has the potential to generate multiple development candidates for Rexahn going forward.
RX-21101 is a polymer conjugated form of docetaxel, a common chemotherapy agent that is now generic but is marketed worldwide under the trade name Taxotere® and had annual sales of $3.1 billion when still under patent. Docetaxel is used in the treatment of breast, ovarian, prostate, and non-small cell lung cancer.
RX-21101 was developed using the Nano-Polymer-Drug Conjugate Systems (NPDCS) platform jointly discovered with the University of Maryland at Baltimore. This technology targets the delivery of currently marketed chemotherapeutic agents directly into cancerous tumors. The direct delivery of chemotherapeutic drugs into the tumors has been shown to result in increased efficacy and reduced toxicity. The NPDCS platform combines existing chemotherapeutic agents with a proprietary polymer carrier that contains a signaling moiety which directs the drug into the tumor. This approach minimizes the levels of freely circulating anti-cancer agents in the body, which can dramatically reduce potential adverse events, and maximizes anti-tumor activity by accumulating the anticancer agent in the cancer tumor. NPDCS is a broad platform that has the potential to generate multiple development candidates going forward.
Despite its commercial success, docetaxel is toxic to all dividing cells in the body and is associated with a high incidence of adverse events including anemia, infection, fever, neutropenia, neuropathy, asthenia, edema, alopecia, nausea and vomiting. These adverse events are the result of high concentrations of free docetaxel in the blood. By minimizing the circulating concentration of free docetaxel in the blood and maximizing the concentration in the cancer tumor, RX-21101 may increase anti-tumor activity and have a lower incidence of adverse events.