Antiviral therapeutics company Chimerix has a new chief medical officer.

Dr. Michelle Berrey, MD, joins the firm from Pharmasset where she also served as CMO. Pharmasset was acquired by Gilead Sciences earlier this year.

“Dr. Berrey is a seasoned drug developer who has established a strong track record in antivirals, in particular with nucleotide analogs,” said Chimerix Chief Executive Officer Kennet Moch. “She joins Chimerix at an important time for the company as our lead compound, CMX001, advances into Phase 3 clinical testing. Her extensive background in antiviral drug development will be invaluable to our already strong team.”

Earlier in her career, Berrey served as vice president, Viral Diseases, Clinical Pharmacology & Discovery Medicine at GlaxoSmithKline. Her work focused on early development of compounds for the treatment of HIV, hepatitis viruses and hepatic fibrosis.

Berrey received her MD from the Medical College of Georgia and a Master of Public Health from Emory University. 

In July, Chimerix licensed rights to its HIV drug candidate to pharmaceutical giant Merck (NYSE:MRK) in a deal that gave Chimerix an up-front payment of $17.5 million.

Chimerix stands to gain up to $151 million more in milestone payments depending on the progress of CMX157. The company would also receive royalties on sales of a successfully commercialized drug. Merck receives exclusive global rights to the compound and takes on the responsbility for developing and commercializing a new HIV drug.

Chimerix’s CMX157 is in a class of antiretroviral drugs called nucleoside reverse transcriptase inhibitors, or NRTIs. The compound delivers concentrations of the active antiviral agent tenofovir diphosphate into cells. CMX157 could offer an alternative to Gilead Sciences’ (NASDAQ:GILD) HIV drug Viread.

Chimerix says its compound is more than 200 times more potent than Viread against all major HIV subtypes that are resistant to current therapies and might work against viruses that are resistant to Viread. CMX157 has has completed phase 1 clinical trials.

Chimerix has raised more than $100 million in venture capital financing including a $45 million series F round last year. The deal with Merck allows Chimerix to focus on its lead antiviral drug candidate CMX001, which is being studied as a way to fight certain DNA viruses in patients who have had stem cell and solid organ transplants.

Chimerix has already met with the Food and Drug Administration to discuss that compound and Moch said in a statement that the company plans to begin enrolling patients in a phase 3 study early next year.