The agreement also gives Merck the option for access to Crucell's AdVac adenovirus-based vector technology.

The news comes as Merck exercises an option and related rights following a December 2006 cross-licensing deal between the two companies, through which Merck gained access to Crucell vaccine production technologies.

Under the terms of the agreement, Crucell also gains rights to certain cell-line technologies developed by Merck for the production of recombinant proteins.

Although the two companies are refusing to disclose which infectious diseases the deal covers, Crucell representatives seemed pleased that the deal further broadens the number of disease areas covered by the popular PER.C6 technology.

The original December agreement between the two companies was also particularly beneficial to Crucell as it allowed the firm to speed up development and delivery of its malaria, tuberculosis and Ebola vaccines, through access to Merck's large scale manufacturing technology for AdVac-based vaccines.

Crucell's PER.C6 technology is widely used in the biopharmaceutical industry, with numerous big names making use of the novel production platform.

The technology uses cell culture for the large-scale production of a range of biologics, including vaccines, antibodies, therapeutic proteins and gene therapy products. Vaccine production using PER.C6 is based on cell cultures, doing away with the need for egg-based manufacturing.

The advantages of the technology are said to lie in its safety profile, scalability and productivity under serum-free conditions, and according to the company is the best characterised and documented cell line available to date.

Although Crucell has its own pipeline of products based on the PER.C6 technology, the company has an impressive list of licensees using the technology to develop their own therapeutic products, including Novartis, Sanofi Pasteur, Lilly, Roche and GlaxoSmithKline, as well as the longstanding relationship with Merck.

Just last week the company also announced a research license for another of its production technologies, this time with US firm Invitrogen.

The company has signed a non-exclusive agreement to gain access to Crucell's Star technology for the production of monoclonal antibodies, which the Dutch firm claims can produce five to ten times more antibody than cell clones produced by other processes.