Sutro Biopharma secured $36.5 million in a Series C financing. The money will support development activities and advance the company's biochemical protein synthesis platform to meet cGMP standards.
Led by Skyline Ventures, the financing round, which consists of two tranches, included participation from new investors Lilly Ventures and Amgen Ventures as well as existing investors SV Life Sciences and Alta Partners. The first tranche of $20 million closed on November 5.
“The financing provides us with sufficient capital to drive our own programs to the clinic and to support our collaborative relationships, which focus on therapeutic proteins that have been inaccessible until now,” says William Newell, CEO of Sutro Biopharma. The company says that it has raised a total of $59.5 million to date.
Sutro is working on protein therapeutics that have site-directed modifications including modifications incorporating non-natural amino acids. In March 2009, the firm said that it achieved therapeutic protein production at the 100 L scale using its open cell-free synthesis (OCFS) technology. This success triggered a second tranche of financing in the firm’s Series B round of $15 million.
Employing its OCFS technology, Sutro scientists produced a therapeutic cytokine in a 100 L scale reaction, demonstrating linear scalability from microliter scale to 100 L scale. The protein product was purified, formulated, characterized, and shown to be of pharmaceutical quality. Sutro exclusively licensed the OCFS technology from Stanford University.
“This achievement allows us to use our platform at a microliter scale for protein discovery and modification with the confidence that new molecules can be immediately scaled for development and eventual commercialization, thus avoiding the delays and challenges of cell-line development inherent in cell-based systems,” Daniel Gold, Ph.D., Sutro’s president and COO, noted at the time.
OCFS technology employs controlled, catalytically driven biochemical reactions to make protein-based therapeutics. An open, cell-free architecture is free from mass transport constraints of the cell wall and membrane as well as requirements for cell growth and viability. The system is thus devoid of the compartmentalization that is generally required for protein folding.