Using our OPopS technology, we are developing a pipeline of promising new drug candidates for the treatment of various indications including osteoarthritis and breast cancer. Our strategy is to license these drug candidates opportunistically to third-party partners in order to maximize the potential for their development and commercialization. The most advanced pipeline product candidates are as follows:

OPT-822/OPT-821: A Cancer Immunotherapy

We are currently developing our carbohydrate-based product candidate OPT-822 combined with OPT-822's adjuvant therapy OPT-821, a carbohydrate-based immunostimulant, for the treatment of metastatic breast cancer. According to the American Cancer Society, breast cancer was the second most common form of cancer among women in the United States, with more than 200,000 new cases and 40,000 deaths estimated in 2005. The survival rate for patients with metastatic breast cancer remains limited, with a median survival of two to three years and a five-year survival rate of less than 20% for those patients diagnosed with late-stage cancer that has metastasized to other parts of the body. In July 2002, we acquired exclusive rights from Sloan-Kettering Institute for Cancer Research, or SKI, to develop and commercialize OPT-822 worldwide. Carbohydrate antigens are known to stimulate the immune response against cancer cells in the body. We have applied OPopS technology to manufacture carbohydrate cancer antigens, including Globo-H, a prominent antigen in breast cancer cells, and sialyl Lewis a, an antigen in breast and small lung cancer cells. OPT-822 is a novel cancer immunotherapy and is composed of Globo H linked to a protein carrier. Optimer's Taiwan subsidiary, OBI, is developing this compound.

CEM-101: Macrolide and Ketolide Antibiotics

Macrolide antibiotics have been marketed for the treatment of upper and lower respiratory tract infections. Macrolides such as azithromycin and ketolides such as telithromycin are related classes of antibiotics which have strong gram-positive activity and inhibit bacterial growth. However, an increasing number of pathogens are now resistant to currently available macrolides and ketolides. One of our leading product candidates developed with our glycooptimization technology, CEM-101, is effective against these resistant bacterial strains. These product candidates have been shown to possess potent activity against multi-drug resistant Streptococcus pneumoniae and Streptococcus pyogenes,common RTI pathogens. CEM-101, the most advanced of these lead candidates, is orally active with potent efficacy in animal models after once-a-day administration. Cempra has licensed from us a library of approximately 500 macrolides related to these two product candidates for RTIs in adults and children, including sinusitis, an infection of the sinus, pharyngitis, an infection of the pharynx, and community-acquired mild and moderate pneumonia. CEM-101 is in Phase 2 clinical development for the treatment of community-acquired bacterial pneumonia (CABP).