In its largest private financing round to date, Chimerix Inc. brought in $23 million to advance antiviral drug development in cytomegalovirus, human papillomavirus and HIV.

New investor Canaan Partners led the Series D round, with additional funding coming from Alta Partners and existing investors Sanderling Ventures, Asset Management Co. and Frazier Healthcare Ventures. To date, Chimerix has raised $39.3 million in venture capital.

"It went very smoothly," Athanasios Maroglou, vice president of business development, said of the financing. Chimerix and the syndicate were able to bring "the terms together very quickly."

Maroglou said the funds should carry the company about three years, during which time the lead programs are expected to get through Phase II development. Chimerix also expects to double its 10-person staff over the next year.

The Research Triangle Park, N.C.-based firm last made headlines in 2003 when it received a four-and-a-half-year, $36.1 million grant from the National Institutes of Health for work on a smallpox drug candidate. CMX001 is a lipid mimic of cidofovir (marketed by Gilead Sciences Inc. as Vistide in HIV) that has shown early activity against multiple types of double-stranded DNA viruses, herpes viruses and adenoviruses. Chimerix is testing the product against smallpox in Phase I, and hopes to move into the required animal efficacy studies by the end of the year. Upon successful completion, the company expects doses of CMX001 to be included in the national stockpile for emergency use. (See BioWorld Today, Sept. 11, 2003.)

"We're continuing to develop our smallpox (candidate)," Maroglou told BioWorld Today, adding that the recent financing will expand the company's pipeline and technology into commercial applications.

In addition to smallpox, CMX001 has demonstrated promise against cytomegalovirus (CMV), a viral infection common in patients undergoing solid organ transplants. Chimerix intends to complete an ongoing Phase I trial in that indication by the end of the year.

"At the same time, we're taking the same active ingredient" in the oral CMX001 compound and "creating a topical treatment for human papillomavirus," Maroglou said. HPV, a viral infection that can lead to cervical cancer, has garnered a lot of attention since the FDA's June approval of Whitehouse Station, N.J.-based Merck & Co. Inc.'s Gardasil, the first-ever vaccine to prevent HPV; however, to date, there are no approved drugs in the HPV treatment market, estimated to be about $1.4 billion worldwide.

Chimerix anticipates filing an investigational new drug application for its topical version of CMX001 "by the end of the year," Maroglou said.

Beyond CMX001, the company has CMX182, a preclinical-stage antiviral aimed at multidrug-resistant HIV. A lipid conjugate of foscarnet, CMX182 has "shown activity against all resistant strains of HIV," he said, adding that three-fourths of all HIV patients are estimated to experience some drug resistance. An IND for CMX182 is expected within the next 12 months.

The company has come a long way since it was founded in July 2002 to develop antiviral therapeutics using its ProLipTag technology, a lipid, prodrug platform designed to create drug candidates with higher potency and targeted delivery capabilities.

As products move further toward late-stage development, Chimerix anticipates "partnering one or more programs" with a large pharma firm for Phase III testing and commercialization, Maroglou said.

Following the financing, Seth Rudnick, of Canaan Partners, and Ed Penhoet, of Alta Partners, are set to join Chimerix's board.