By Randall Osborne

West Coast Editor

With four antibody products in preclinical stages and three discovery and development programs under way, TolerRx raised $17 million in a Series B financing to push its platform designed for boosting the body¿s tolerance of protein therapeutics.

The money is expected to take Cambridge, Mass.-based TolerRx ¿well into 2003,¿ said Douglas Ringler, CEO and co-founder of the 16-employee firm, which started with a Series A round in December 2000, raising $6 million.

The Series B financing was led by current investor HealthCare Ventures, of Princeton, N.J., and includes new investors Skyline Ventures, of Palo Alto, Calif.; Rho Ventures, of New York; and Vertex Management, of Singapore.

TolerRx¿s lead product is TRX1, a humanized monoclonal antibody headed for clinical trials for use as a combination therapy designed to induce tolerance to treatments such as Factor VIII and chimeric antibodies. It¿s also being investigated as a primary therapy in transplantation and immune disorders, such as rheumatoid arthritis and multiple sclerosis.

¿We¿ve not sought any partners, although we¿ll be looking to partner certain clinical indications, and certainly with the TolerMab technology,¿ which makes an antibody become immunologically recognized as ¿self¿ while maintaining therapeutic activity for long-term benefit, Ringler said.

¿The first partners will be largely associated with trying to induce tolerance to soluble proteins,¿ he added.

Preclinical data in monkeys have shown TRX1 induced antigen-specific tolerance in non-human primates, yet kept immunocompetence as well as immune response to new antigens. Clinical trials are expected to begin in mid-2002.

TolerRx¿s three-step strategy will focus first on developing adjunctive therapies for protein therapeutics, then on transplantation treatment, and then on autoimmune disorders.

Transplantation comes first ¿because the exposure to antigens during the transplant are well defined and controlled,¿ Ringler told BioWorld Today. ¿In that setting, we think we can understand the rules a little bit quicker.¿

The company also aims to use its new money for research and development efforts aimed at identifying new tolerance targets and genes.

TolerRx has established research and discovery programs in the field of T-regulatory cells and dendritic cells, which are the immunological mediators of tolerance. With the University of Oxford in the UK, the company is identifying novel genes and targets differentially expressed on those cells, with an eye toward developing ¿tolerogenic¿ therapeutics.

Ringler said the firm expects to have 25 employees by the end of this year, and about 45 to 50 at end of next. As a result of the financing, Yasunori Kaneko, managing director of Skyline, will join TolerRx¿s board of directors.