Antibody therapeutics specialist f-star raised €15 million (roughly $22 million) in a financing round led by SR One, the corporate venture capital arm of GlaxoSmithKline (GSK). All of f-star’s existing investors also participated. The firm said the capital injection will allow it to progress its first product candidates through IND-enabling studies and into the clinic.
f-star is exploiting its Modular Antibody Technology to develop antibody and antibody fragment-based therapeutics. The platform allows the introduction of additional binding sites into antibodies and antibody fragments by engineering the non-CDR loops of constant or variable domains. The firm claims the platform enables the design of small-sized antibody fragments with full antibody functionality (Fcab™), or full-length antibodies with additional functionality (mAb²).
“f-star has shown that its Modular Antibody Technology platform can generate multiple high-affinity biotherapeutics against targets of varying precedence and novelty in both single- and bi-specific formats,” remarks SR One partner Deborah Harland, Ph.D., who has been appointed to f-star’s supervisory board. “We believe the platform has the potential to generate numerous novel differentiated biologics with advanced efficacy, tissue penetration, and targeting capabilities compared to traditional antibodies.”
Fcab™ (antigen binding Fc) molecules are built around a conservative engineered protein scaffold comprising an antibody’s CH2 and CH3 domains, folded as a roughly 50 kDa homodimer with two identical antigen binding sites engineered into the CH3 domains. F-star claims that the molecules have a number of advantages over traditional antibodies. These include the small size, which facilitates tissue penetration; the ability to produce resulting Fcabs in E. coli, yeast, or mammalian cells; and the ability to fine-tune effector functions.
In contrast, mAb² antibodies are full IgG antibodies with two additional binding sites engineered into the CH3 domains. These extra sites provide the potential to generate molecules with additional binding sites to same antigen, binding sites to a second disease antigen, or tissue-specific binding sites that target the drug to specific cell types, f-star claims.
The firm is exploiting its platform for the development of a pipeline of therapeutic candidates in house, and also through antibody therapeutic collaborations and partnerships.
In November 2010 f-star signed a collaboration and license agreement with Boehringer Ingelheim (BI) centered on the discovery of new antibody-derived therapeutic products based on f-star’s Modular Antibody Technology, against up to seven targets in multiple therapeutic areas nominated by BI.