2006 CORPORATE OVERVIEW

OVERVIEW is a company specializing in the discovery and development of biotherapeutics utilizing monoclonal technology.

COMMERCIAL PRODUCT Xolair® () The company’s first-approved drug, Xolair, is the first BUSINESS STRATEGY anti- (anti-IgE) antibody to be brought to It is the objective of Tanox to become a the market. Xolair achieved 2005 U.S. sales of $320 million. profitable company by Tanox received royalties, manufacturing-rights payments and developing, manufacturing and marketing profit-sharing revenue ($44.7 million in 2005) from its Xolair products. Key aspects alliance with , Inc. and Pharma AG. of the company’s growth strategy include: Xolair is approved in nearly 50 countries and marketed in 15. Expanding indications for Xolair Establishing proof-of-concept in key Results of recent Xolair studies were presented at the 2006 meeting of the American Academy of Allergy and pipeline programs Immunology, which detailed improvements in long-term Advancing its product pipeline to create control in patients using Xolair. Novartis is also commercial opportunities conducting a Phase 3 clinical trial of Xolair for the treatment Forming strategic collaborations to support of pediatric asthma. Additionally, Genentech is conducting development and commercialization of a five-year post-marketing study of Xolair designed to its products compare the effectiveness and long-term safety profile of patients with mild-to-severe persistent IgE-mediated asthma who have been treated with Xolair, with patients of similar profile, but who have not been treated with Xolair.

DRUG DISCOVERY & DEVELOPMENT PROJECTS

VValidationalidation Optimization PrPreClinicale-Clinical PhasePhase 11 PhasePhase 22 PhasePhase 33 TARGETTARGET

TNX-355 CD4 HIV / AIDS

TNX-832 Tissue ALI / ARDS Factor TNX-650 HODGKIN'S IL-13 LYMPHOMA TNX-650 INFLAMMATORY IL-13 DISEASE TNX-833 Tissue CANCER Factor TNX-234 AGE-RELATED Factor D MACULAR DEGENERATION TNX-717 OSTEOPOROSIS Pro-Apoptotic Factor TNX-558 INFLAMMATORY Complement DISEASE C5a ......

www.tanox.com © 2006 TANOX, INC. ALL RIGHTS RESERVED. Corporate Offices Houston, Texas RECENT HIGHLIGHTS 2006 CATALYSTS Manufacturing Facility San Diego, Presented TNX-355 Phase 2 efficacy Finalize discussions with FDA and safety data at the International regarding further development Technology Monoclonal AIDS Conference in August of TNX-355 Reported second-quarter revenues File IND for TNX-650 in an Leadership of $12.7 million inflammatory-disease indication Danong Chen, Ph.D. President & CEO • Reported second-quarter Xolair Complete preclinical studies for Edward Hu royalty revenue of $9.9 million TNX-833 in cancer Senior Vice President & Initiated TNX-355 discussions with Advance and expand preclinical Chief Operating Officer the Food and Drug Administration programs Bing Yao, Ph.D. Vice President, Research Greg Guidroz Vice President, Finance Katie-Pat Bowman Vice President, General Counsel & Secretary CLINICAL CANDIDATES Brian Kim TNX-355 load than did patients in the placebo Vice President, Quality The company’s lead drug candidate, plus OBR group. In addition, the Hugo Santos TNX-355, is the most-advanced mono- 48-week results showed that patients Vice President, Human Resources clonal antibody in development for the who received TNX-355 with OBR treatment of HIV. TNX-355 is a humanized experienced a significant increase in Employees 200 monoclonal antibody that is administered CD4+ cells compared to patients in intravenously. The drug candidate is part the placebo-OBR group. History of an emerging class of HIV therapies Founded in 1986 known as viral-entry inhibitors, but is TNX-832 distinct from other inhibitors in that it TNX-832 is in a phase 1/2 clinical binds to CD4 receptors, the primary target trial for the treatment of acute lung of HIV infection. injury/acute respiratory distress syndrome. A humanized version of Stock Data In 2005, a Phase 2 study of TNX-355 met TNX-832 is in preclinical development Public: 2000 its primary endpoint of mean viral-load as a cancer therapy. NASDAQ: TNOX reduction from baseline at 24 weeks. 52-week Trading Range: TNX-650 High $21 Low $11.57 Results of the Phase 2 study at 48 weeks TNX-650 is in a Phase 1 trial for the Shares Outstanding: 45 million continued to show that patients who treatment of Hodgkin’s lymphoma Market Cap: $563 million received TNX-355 plus an optimized and is also in preclinical development Avg. Daily Vol.: 171,502 shares background regimen (OBR) had a as an inflammatory-disease treatment. As of September 15, 2006 considerably greater reduction in viral

Analyst Coverage

Bear Stearns This fact sheet contains forward-looking statements based on current expectations that involve a number of risks CIBC World Markets and uncertainties. We typically identify forward-looking statements by using terms such as “may,” “should,” First Albany Capital “could,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “predict,” “potential” or similar words, although we express some forward-looking statements differently. You should be aware that actual events could differ Global Crown Capital materially from those suggested in the forward-looking statements due to a number of factors, including the Lazard Capital Markets continued market acceptance of Xolair®; the results of our collaborators, Genentech and Novartis, in growing sales of Xolair; our ability to successfully recruit participants for human clinical trials; our ability to successfully Leerink Swann & Company manufacture products for initiation or continuation of human clinical trials; failure to achieve positive results Prudential Equity Group in clinical trials; and the strength of our patent portfolio. Prospective investors should carefully consider the information contained in the company’s Form 10-K and other Securities and Exchange Commission (SEC) Rodman & Renshaw filings, including the sections titled Risk Factors and Management’s Discussion and Analysis of Financial Summer Street Capital Partners Condition and Results of Operations, when evaluating an investment in the shares of Tanox Common Stock. As of September 15, 2006 The Tanox logo is a registered trademark with the U.S. Patent and Trademark Office.

For more information: Steve Sievert, Investor Relations & Corporate Communications 713.578.4211 | [email protected]