Using polyglutamate drug delivery technology, we are developing a new way to deliver paclitaxel preferentially to tumor tissue. This approach could potentially reduce the toxic side effects of paclitaxel to normal organs and tissues and improve its anti-tumor activity.
One of the unique characteristics of our product candidate OPAXIO™ (paclitaxel poliglumex, CT-2103; formerly known as XYOTAX) is that it links, or conjugates, paclitaxel to the biodegradable polymer polyglutamate.
Based on preclinical animal studies and clinical trial data, we believe that OPAXIO may be able to achieve a number of benefits over existing taxanes, including:
Unlike vessels in healthy tissue, vessels in tumor tissue have openings, or pores, that make them porous to large molecules. OPAXIO molecules, which are larger than those of standard paclitaxel, leak through these pores and are preferentially trapped and distributed in the tumor tissue.
Once in the tumor tissue, OPAXIO is taken up by tumor cells through a cellular process called endocytosis. Because the biopolymer OPAXIO is made of biodigestible amino acids, it is slowly metabolized by lysosomal enzymes (principally cathepsin B) inside the lysosome in the tumor cell. This metabolism releases the active chemotherapy agent, paclitaxel into the tumor.
In addition to the potential metabolic advantages, polymer-linked cancer drugs are inactive while circulating in the bloodstream, which may also lower toxicity compared to the active cancer drug substance alone.
We licensed the worldwide exclusive rights to polyglutamate and related polymers and their applications from PG-TXL Company in 1998. The technology was originally developed at The University of Texas M.D. Anderson Cancer Center. The initial patent, issued in November 1999, covers polyglutamate and related polymers coupled with commonly used cancer drugs such as paclitaxel, docetaxel, etoposide, teniposide, or camptothecins. The patented technology covers formulations of polyglutamate-conjugated paclitaxel that also include the use of human serum albumin and conjugation to epothilones.
Through this novel polymer technology we have the opportunity to build a portfolio of potentially safer and more effective versions of well-known anti-cancer agents such as taxanes. Taxanes such as paclitaxel are widely used for the treatment of various solid tumors, including non-small cell lung, ovarian, breast, and prostate cancers. We believe that our polymer technology may lower the risks inherent in developing new drugs because we are linking polymers to well-defined and widely used classes of chemotherapy drugs, including taxanes.
Development: OPAXIO™ See our Development section for more information on the application of this technology to our product candidate OPAXIO, in pivotal clinical trials for non-small cell lung and ovarian cancer.