Cara Therapeutics Inc. topped off its Series C financing with an additional $5 million investment, bringing the round's total to $24 million.

The Tarrytown, N.Y., company was founded in 2004 on technology related to peripherally acting analgesics acquired from Ferring Pharmaceuticals, a Saint-Prex, Switzerland-based firm that in return gained an equity position in Cara. At the same time, Cara brought in GPCR drug discovery technology from the University of Glasgow in Scotland. It is developing products for pain and inflammatory conditions.

"I was very pleased with the high level of interest shown in participating in the Series C financing from the investment community," Derek Chalmers, president, CEO and a co-founder of Cara, told BioWorld Today. "This financing provides Cara with sufficient runway to reach considerable valuation creation points for our next two clinical development programs."

Cara had raised about $7 million total in two previous financing rounds, the money coming mostly from company insiders and high-net-worth individuals. Chalmers said the company's position in peripherally acting analgesics is what attracted the new funding from venture capitalists.

Cara's lead program focuses on compounds that are selective agonists of the kappa opioid receptor, while its second program focuses on peripherally acting agents that selectively target the cannabinoid-2, or CB2, receptor.

"Both those areas were very attractive to investors," Chalmers said, noting that unlike existing agents, Cara's products do not act on mechanisms in the brain. The mu receptor is the most common opioid target, while CB1 receptors are localized mainly in the brain.

Cara's lead product from the kappa opioid program, CR665, was partnered in January 2006 with ALZA Corp., a Johnson & Johnson company based in Mountain View, Calif. That deal came following data from a Phase Ia trial that demonstrated safety and tolerability.

ALZA got worldwide rights to CR665 and a backup compound, CR666, in exchange for undisclosed up-front payments and potential milestone and royalty payments. ALZA also got rights to use its technologies to develop another formulation of the product, the intravenous version of which is in a Phase IIa trial.

Chalmers said Cara retained a co-promotion option in the U.S. on the intravenous formulation.

The intravenous formulation likely would target acute clinical indications, Chalmers said, while the ALZA formulation would be used for chronic conditions.

The companies did not disclose ALZA's formulations plans, but ALZA has a focus in transdermal delivery.

Cara's next program to move into the clinic also is expected to be a peripherally acting agonist of the kappa opioid receptor, that one in ophthalmic indications such as reducing intraocular pressure in glaucoma and treating ocular pain and inflammation, Chalmers said. Trials are expected to start in 2007, he said.

Following that into the clinic is expected to be compounds from the CB2 program. Chalmers said those compounds are very selective for the CB2 receptor over the CB1 receptor, giving them the potential to provide pain relief without central nervous system side effects.

The company's drug discovery technology is called DimerScreen, which is designed to specifically and selectively identify molecules interacting with G protein-coupled receptor dimers, allowing for discovery of new targets within the GPCR superfamily. Chalmers said Cara is at the screening stage on molecules targeting specific GPCR heterodimers in pain pathways and on certain immune cells.

Co-founders of Cara along with Chalmers were Frédérique Menzaghi, vice president of research and development, and Michael Lewis, chief scientific adviser. Chalmers and Lewis also were among the co-founders of Arena Pharmaceuticals Inc.

Cara has 35 employees.

The first, $19 million tranche of the Series C financing closed in November. Investors included MVM Life Science Partners, Alta Partners and Ascent Biomedical Ventures. New investors in the $5 million tranche were Scottish Widows Investment Partnership and Mitsubishi International Corp. Ascent was the only venture capital firm to participate in pre-Series C funding.