Visterra Inc.'s $30 million series B financing brought in more than expected and leaves the company with "a clear path for the next couple of years" to pursue therapies in dengue fever and influenza, said CEO Brian Pereira.

The Cambridge, Mass.-based firm's phase I antibody VIS410 targets flu and preclinical VIS513 is designed to neutralize all four serotypes of dengue in one dose, Pereira told BioWorld Today.

"Our therapeutic is not [to be used] instead of the flu vaccine; ours is therapeutic for flu," he said, noting that Tamiflu (olsetamivir, Roche AG) and Relenza (zanamivir, Glaxosmithkline plc) for ambulatory flu patients reduce symptomatology "by about a day," but there is nothing licensed for the more serious flu patients that VIS410 is being developed to treat, also with a single dose. About 250,000 people are hospitalized with flu each year, and as many as 50,000 die.

"In years that [flu vaccine-makers] get the strains right, the coverage is good, but oftentimes, the predicted strain is wrong," Pereira said. VIS410 covers the whole landscape. Even when the correct strains are chosen, the vaccine coverage for old, sick and immunocompromised patients is less than optimal. "We expect to finish the phase I trial in short order, and transition to a phase II proof-of-concept study in 2015," with results by the end of next year, he said.

Visterra has finalized its research candidate in dengue, finished studies that would enable an investigational new drug application, and is moving toward the manufacture of clinical trial materials, with hopes of entering phase I before 2015 is over.

"What's not universally known is that dengue is by far the commonest insect-borne disease in the world," with 400 million infections recorded every year, Pereira said. "In the past, dengue was largely a developing-world tropical disease," but with industrialization, the movement of people and global warming, the fever has begun to emerge in temperate climates in the industrialized world, he said.

"The good news is that, since there is a complete unmet need for [dengue and flu], clinical-trial requirements in patient numbers is modest," Pereira said. "The second advantage is that this is high on the radar screens of U.S. and ex-U.S. governmental agencies, in terms of support."

Like the firms Cerulean Pharma Inc. and Momenta Pharmaceuticals Inc., both also of Cambridge, Mass., Visterra originated from research in the laboratory of Massachusetts Institute of Technology professor Ram Sasisekharan. The company first made itself known in 2012 by unveiling data with VIS410 at the Interscience Conference on Antimicrobials and Chemotherapy, and raised $8 million in a series A financing late last year. (See BioWorld Today, May 23, 2003, Sept. 12, 2012, March 25, 2013, and Dec. 2, 2013.)

Visterra's atomic interaction network analysis approach lets the firm quantitatively score each amino acid of a protein in terms of its network of interactions, covalent and noncovalent, with other amino acids. The firm thereby was able to analyze flu A subtypes, look at three-dimensional structures, define targets and identify the epitope that is structurally conserved.

"When a target is polymorphic and mutated, we are probably in the best position to create a single solution," Pereira said. "It's what we do better than anybody else." Both boxes are checked in infectious diseases. "For non-infectious targets, mutation is less of an issue but polymorphism is an issue," he said. "There, too, while our technology is well suited to create a single solution, it's a little different from having both polymorphism and mutation."

Pereira said his firm "would not shut the door to the right partner who wants to pursue the right [non-infectious] target and funds it," as long as the project is "not a distraction from our core mission." Visterra will consider partnerships for both of its infectious programs, too.

"We have no commercial infrastructure, and we don't expect to build one in the short term," Pereira said. With the dengue compound, "we will clearly partner in the rest of the world, and flu will probably be the same," with Visterra retaining U.S. rights. "That's an issue we'll look at a few years down the road," he added, pointing out that the company is working on more targets yet to be disclosed.

The series B round was co-led by new investors Merck Research Labs Venture Fund, Vertex Venture Holdings Ltd. and Temasek. Existing investors – Polaris Partners, Flagship Ventures, Omega Funds and Alexandria Venture Investments – and a new investor, Cycad Group, also took part in the upsized financing.