Titan Pharmaceuticals, Inc. Reports Positive Results From Studies of RB94 Cancer Therapy; Separate Studies Demonstrate Novel Agent Has Strong Antitumor Activity.

Business Editors/Health & Medical Writers

SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)--June 4, 2001

Titan Pharmaceuticals Inc. (ASE: TTP) reported positive results from two separate preclinical studies demonstrating the ability of Titan's RB94 cancer therapy to arrest growth and induce apoptotic cell death in animal models using human tumor cells.

These studies were designed to test the potential effectiveness of RB94 in the treatment of human tumors in head and neck squamous cell carcinoma and pancreatic cancer. Results from both studies were presented on June 2, 2001, at the American Society of Gene Therapy conference in Seattle.

The results of the study in head and neck cancer were presented by Bert O'Malley, Jr., M.D., Director, Otolaryngology-Head & Neck Surgery, and colleagues, at the University of Maryland Medical School. This study of an animal model of human head and neck squamous cell carcinoma evaluated tumor treatment with adenoviral based RB94 (Ad-RB94), as well as radiation treatment and control treatments. The study results demonstrated that RB94 effectively inhibited tumor growth, acting through the novel combined mechanism of tumor cell growth arrest at the G2/M phase of the cell cycle, and inhibition of telomerase activity, leading to tumor cell death. This unique property of RB94 suggests it is an excellent candidate for combination with radiation therapy, as tumor cells are most sensitive to radiation in the G2/M phase. As predicted by this discovery, the study also demonstrated that the combination of RB94 and radiation therapy significantly enhanced tumor cell death beyond treatment with radiation alone, suggesting that RB94 may have important utility in the clinical treatment of head and neck cancer.

Commenting on these results, Dr. Bert O'Malley stated that, "The RB gene is a master control switch for cell division and a major regulating factor against tumor cell growth. Studies to date with RB94 suggest it is an enhanced, more potent form of the RB gene. These properties make it an excellent candidate for improved treatment of head and neck cancer and potentially many other cancers."

Results of the second study in the treatment of pancreatic cancer were presented by Dr. Adela Mazo, Professor of Biochemistry and Molecular Biology, and colleagues, at the University of Barcelona and Institut de Recerca Oncologica in Barcelona, Spain. In this animal study using human pancreatic cancer cells, mice were given intratumoral injections of AD-RB94, after which the tumors were measured and tumor volumes calculated. RB94 again demonstrated significant activity as an anticancer agent, demonstrating growth arrest and tumor cell death. Importantly, the antitumor effect of the novel RB94 gene was significantly greater than that seen for the wild type RB gene in these studies. From these results, the investigators concluded that the enhanced efficacy of RB94 demonstrated in this model suggests a potential role for RB94 in the treatment of human pancreatic cancer.

RB94 is a novel gene based product being developed by Titan as a potential treatment for several cancers, including head and neck cancer, pancreatic cancer and lung cancer. RB94 is a modified version of the retinoblastoma (RB) gene, a tumor suppressor gene that is directly involved in regulating the cell cycle and causing apoptosis (programmed cell death). The RB gene plays an important role in cell replication and in preventing cancerous cell transformation and proliferation. Loss of RB gene activity is associated with a majority of solid tumor cancers.

Commenting on the results of these studies, Dr. Louis R. Bucalo, Chairman, President and CEO of Titan Pharmaceuticals, stated, "The anti-tumor activity demonstrated by RB94 against both head and neck squamous cell carcinoma and pancreatic cancer in these preclinical studies is very encouraging and provides further evidence that RB94 may have potential to become a broad spectrum cancer therapeutic agent. Additional studies are in progress to explore the therapeutic potential of RB94 in these and other types of cancer."

About Titan Pharmaceuticals

Titan Pharmaceuticals, Inc. (ASE: TTP) is a biopharmaceutical company focused on the development and commercialization of novel treatments for central nervous system (CNS) disorders, cancer and other serious and life-threatening diseases. Titan has assembled a deep pipeline of products utilizing novel technologies that have the potential to significantly improve the treatment of these diseases. Titan also establishes important partnerships with multinational pharmaceutical companies and government institutions for the development of its products. Zomaril(TM), Titan's novel drug for the treatment of schizophrenia, is being developed through a corporate partnership agreement with Novartis Pharma AG. Titan has also entered into a corporate partnership with Schering AG to develop and commercialize Spheramine(R), a novel treatment for Parkinson's disease. In addition, several clinical programs in cancer therapy are supported by large oncology cooperative groups that are funded by the National Cancer Institute.

The press release may contain "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Such statements include, but are not limited to, any statements relating to the Company's development program and any other statements that are not historical facts. Such statements involve risks and uncertainties, including, but not limited to, those risks and uncertainties relating to difficulties or delays in development, testing, regulatory approval, production and marketing of the Company's drug candidates, unexpected adverse side effects or inadequate therapeutic efficacy of the Company's drug candidates that could slow or prevent product development or commercialization, the uncertainty of patent protection for the Company's intellectual property or trade secrets and the Company's ability to obtain additional financing if necessary. Such statements are based on management's current expectations, but actual results may differ materially due to various factors, including those risks and uncertainties mentioned or referred to in this press release.