BioWorld International Correspondent

CureVac GmbH banked €13 million (US$17.7 million) in a second closing of its Series B round, taking the total value of the transaction to €35 million and accelerating the development of its pipeline of mRNA-based cancer vaccines.

There was no change in the Tübingen, Germany-based company's investor roster, however. The funding came from DH Capital GmbH & Co. KG and OH Beteiligungen GmbH & Co. KG, both Heidelberg, Germany-based funds owned by the family of SAP AG co-founder Dietmar Hopp, one of the most active investors in Germany biotechnology at present.

Hopp's funds had invested €22 million in a first closing of the round, disclosed in January 2006. The company has raised €38 million in total, since it was spun out of the University of Tübingen in 2000 to develop stabilized mRNA-based cancer vaccines.

The new funding was motivated both by the current strong momentum in the wider RNA market and by progress within CureVac's own research programs. "We obtained quite thrilling preclinical results on our RNActive molecule," CureVac CEO and co-founder Ingmar Hoerr told BioWorld International. The most recent expression data surpassed what the company was able to generate around the time of the first financing.

CureVac's RNActive platform comprises a series of proprietary chemical modifications to mRNA that improve its stability and biological activity, so that it can be used to elicit immune responses against tumor antigens.

"I think the technology is very powerful because you can combine different antigens," Hoerr said. It also could be superior to DNA-based approaches, where duration of expression is not controlled.

"The major drawback with plasmids is the stability issue. You don't have a half-life. You don't know how long the plasmid is expressed," he said.

The company has been able to assemble single RNActive molecules up to 11 kilobases in length so far. They can encode entire proteins or individual epitopes that are known to be immunologically active. Motifs that trigger Toll-like receptor (TLR) 7 and TLR-8 also can be included in the construct, to further boost the immune response. "RNA is immunogenic as well. It's a kind of adjuvant," Hoerr said.

The highly purified molecules, which are generated using a GMP-level bacterial production system, can be delivered via injection of naked mRNA or encapsulated with carrier peptides.

CureVac aims to move its first therapeutic vaccine into a Phase I/II clinical trial in prostate cancer in 2008, to evaluate safety, toxicity and immunogenicity.

The additional funding will enable the company to begin at least one more internal development project, while it also aims to enter partnerships with third parties.