Shares in Crucell leapt 12% on the news that the Dutch biotechnology firm has signed a deal potentially worth around 77 million euros with Sanofi-Aventis’ vaccine unit which will focus on developing next-generation rabies jabs.

Sanofi Pasteur has signed an exclusive collaboration and commercialisation agreement to get access to Crucell's rabies monoclonal antibodies, which are next-generation biologicals to be used in association with rabies vaccine for post-exposure prophylaxis against the disease. In cash terms, the Leiden-based firm will continue to develop and then manufacture the final product and in return will get an initial sum of 10 million euros. It will be eligible for milestone payments of up to 66.5 million euros.

Rabies causes 55,000 deaths a year, mostly in rural areas of Asia and Africa, and while in the last 20 years, over 20 million people in 100 countries have been treated with Sanofi Pasteur's rabies products, there is still no treatment for rabies once symptoms of the disease have appeared. The companies noted that post-exposure prophylaxis for severe bites requires both active immunisation, using currently-marketed vaccines and passive immunisation in the form of rabies immunoglobulins. They now hope that rabies MAbs will be “an innovative and potent alternative to currently-used RIGs”.

Crucell has developed a combination of two rabies MAbs that has shown results comparable to current immunoglobulin products in preclinical trials, while Phase I studies show its product is well tolerated and provides the expected immediate passive neutralising activity. It can also be safely administered in combination with a rabies vaccine without interfering with the latter’s ability to induce an active immunity.

The US Food and Drug Administration has given the development program a fast-track designation, which means that Crucell can submit data to the agency as it becomes available, rather than all at once. Phase II trials are expected to start in the first half of 2008 and Crucell is forecasting peak sales of its rabies antibody cocktail of over $300 million.