Talizumab (TNX-901) is a humanized monoclonal antibody that was under development by Tanox in Houston, Texas as a new-concept therapeutic for allergic diseases.

[1][2][3] In the original collaborative agreement signed between Tanox and Ciba-Geigy in 1990 to co-develop the anti-IgE antibody program, the two companies agreed to select a top candidate for manufacturing process development and clinical trials.

The managers of Tanox agonized over the decision, in the midst of very positive results from the phase II studies of TNX-901 on peanut allergy.

If an ordinary anti-IgE antibody, which does not possess the unique set of binding specificity of CGP51901 or TNX-901, were injected into a human subject, it would probably invariably induce an extensive scale of mast cell and basophil activation and hence the development of anaphylactic shocks.

Under the collaborative agreement between Tanox and Ciba-Geigy, cGMP-grade CGP51901 was manufactured in a 500-liter bioreactor facility in Tanox in Houston, Texas and a Phase I trial on individuals with pollen sensitivity was carried out in Southampton, UK in 1991–1992,[13] and a Phase II trial on patients with severe sensitivity to mountain cedar pollens was performed in three medical centers in Texas in 1994–1995.

Another anti-IgE antibody with identical antigen-binding characteristics is already on the market for allergic asthma and immunoglobulin E-mediated food allergy, under the trade name Xolair (omalizumab).

Omalizumab is an anti-IgE monoclonal antibody, which was placed in a development program under a tripartite partnership formed by Tanox, Novartis, and Genentech in 1996.