BioWorld International Correspondent

LONDON - Oxford Immunotec Ltd. raised $40 million in its third private funding round, providing the backing for the U.S. launch of its T-SPOT.TB diagnostic test for tuberculosis.

The round was co-led by new investors Clarus Ventures of Boston, and Wellington Partners of Munich, Germany, with the National Technology Enterprises Company in Kuwait also joining as a new investor. Current investors, Prelude Trust, Quester and the Dow Chemical Company followed on.

T-SPOT.TB is the first regulatory-approved method for quantifying antigen-specific T cells produced in response to infection. The test is sensitive enough to detect a single T-cell in a blood sample and can be used to monitor their numbers over the course of an infection. The ability to monitor the level of infection is critical because patients often feel better and discontinue their course of drugs before the infection is cleared.

Abingdon, UK-based Oxford Immunotec's aim is to replace the tuberculin skin test, a century-old test that takes days to complete and is not sensitive to latent infections.

The product is on the market in Europe, Canada and more than 40 other countries. Pending final FDA approval, the new money paves the way for the U.S. launch, the largest market for the product. Peter Wrighton-Smith, CEO, said the test will be important in fighting the global resurgence of tuberculosis. "By securing this significant funding, we are fully prepared for approval and market launch of T-SPOT.TB in the U.S.," he said.

The worldwide TB diagnostics market was about $900 million in 2006, with the diagnosis of latent TB infection in industrialized countries that previously regarded the infection as eradicated accounting for approximately $240 million. While use of the test takes time to bed in, evidence that T-SPOT-TB could help in controlling tuberculosis is beginning to accumulate.

For example, a study released earlier this month shows the test is cost-effective when used in contact tracing investigations. The study, based on data from the Lausanne University Medical Polyclinic, Switzerland, calculated the cost-effectiveness of screening by the Tuberculin Skin Test (TST) alone, T-SPOT.TB alone, and a two-step approach in which subjects that were positive by the TST were then tested with T-SPOT.TB. The most cost-effective was the T-SPOT.TB alone.

While to date Oxford Immunotec has devoted its resources to commercializing the tuberculosis test, the technology platform is relevant to the diagnosis of other chronic infections and as a tool in vaccine development.

Rainer Strohmenger, a general partner at Wellington Partners, said it was the breadth of potential applications that persuaded the firm to invest in Oxford Immunotec. "[T-SPOT] currently provides the most sensitive and specific method for diagnosis of latent tuberculosis infection. However we also foresee potential applications in the diagnosis of chronic infections other than tuberculosis and in any quantitative measurement of specific T-cell activation, where Oxford Immunotec has a strong IP position," he said.

The company's patents were opposed by Sanofi-Pasteur, the vaccines arm of Sanofi-Aventis SA, but in April, the dispute was settled when Oxford Immunotec agreed to license the technology platform for use in Sanofi's vaccines programs.