Kyto advancing with a program for humanization of the mAbTCR23 antibody

Dec 4 2009

Kyto Biopharma Inc. (OTCBB: KBPH), is a biotechnology company focused on developing monoclonal antibody and oligonucleotide targeting therapeutics based on a proprietary vitamin B₁₂ platform for the treatment of various forms of cancer.

Vitamin B₁₂ regulates one of two major cellular pathways for the production of folates, the progenitor for the synthesis of DNA. Cancer cells require increased levels of vitamin B₁₂ for proliferation than do normal cells and in turn over-express the receptor for the uptake of vitamin B₁₂. Using its technology, Kyto is targeting the over-expression of the vitamin B₁₂ receptor in the treatment of various forms of cancer. The primary approach developed by Kyto is directed at selective targeting of the vitamin B₁₂ receptor in cancer cells by monoclonal antibodies. This approach intends to minimize many of the potential complications arising from current chemotherapy treatments such as acute systemic toxicity. The Kyto technology is intended to exploit over-expression of vitamin B₁₂ receptors in cancer cells by coupling toxins to targeting the vitamin B₁₂ receptor monoclonal antibodies.

Kyto has previously announced that through its research and co operation agreement with SUNY, it has been able to identify and purify the protein and gene encoding receptor for the cellular uptake of vitamin B₁₂. This seminal discovery was the subject of an article entitled “The protein and the gene encoding the receptor for the cellular uptake of transcobalamin - bound cobalamin” and which was published in the scientific journal “Blood” in January 2009, by Dr. Edward Quadros and his colleagues at SUNY.

Kyto’s Research and Development strategy is to develop monoclonal antibodies to the vitamin B₁₂ receptor as specific delivery vehicles for cytotoxic payloads. In addition Kyto is identifying select malignancies that are most sensitive to the vitamin B₁₂ receptor antibody-payload conjugates. Kyto has recently achieved a critical milestone in that respect.

Kyto has been successful in developing a specific murine monoclonal antibody to the transcobalamin receptor. The antibody identified as mAbTCR23, has been demonstrated to be highly effective in targeting cancer cells and in inhibiting cell proliferation in a number of cell lines including solid tumors and lymphnoid malignancies. The conjugation of the mAbTCR23 antibody to saporin, a highly effective intercellular cytotoxic agent, did not affect the biological activity of the antibody.

The mAbTCR23 –Saporin Conjugate studies demonstrate that i. A monoclonal antibody to the Transcobalamin receptor is an effective reagent for targeting cancer cells. ii. The effective dose of the antibody-saporin conjugate is in the nanomolar range, a concentration easily achievable in humans. iii. The target for toxin delivery appears to be specific for rapidly dividing cells and therefore would provide selective targeting to rapidly proliferating cancer cells. iv. The low dose of the antibody-toxin conjugate required is anticipated to limit systemic toxicity in humans.

“The development of an effective high affinity antibody-toxin conjugate to the transcobalamin receptor is a significant milestone for Kyto and shows definitive evidence to the validity of the Kyto technology”, stated Dr. Uri Sagman, one of the founders and a director of Kyto.

Kyto is proceeding with plans for achieving the next critical milestones and is advancing with a program for humanization of the mAbTCR23 antibody. Kyto estimates that a humanized version of mAbTCR23 will be completed in late 2010. “Over the next few months, we shall concentrate on the humanization of the antibody while we start looking for a partner who can participate with Kyto to advance the platform through Phase I testing. As we see more evidence of renewed interest in the pharmaceutical sector at the pre-clinical level, we are encouraged in our belief that our focus will be rewarded” said Georges Benarroch, President, one of the founders of Kyto, President of Credifinance Capital, and Kyto’s largest shareholder.

http://www.kytobiopharma.com/