E. Lawrence Hill and Daniel Ratto, executives brought in to run biopharmaceutical firm Trimeris in a management shakeup last March, are leaving the company as of Jan. 2, Trimeris said in a Securities and Exchange filing late Wednesday.

The news came as another SEC filing from HealthCor Management, an investor in Trimeris, disclosed that it had increased its ownership share to 17.79 percent, or close to 4 million shares of some 22 million shares outstanding.

In August, HealthCor, a New York investment firm, called for Trimeris not to pursue development of a new HIV drug and also to consider selling the company. Trimeris (Nasdaq: TRMS) sells the AIDS drug Fuzeon in partnership with Roche Pharmaceuticals.

Last week, Trimeris and Roche dropped development of an alternative means of administering Fuzeon, which must be taken twice a day by injection.

On Thursday, Andrew Graham, director of finance at Trimeris, said the company would continue development of its HIV drug candidate “at this time.”

Hill and Ratto will continue to work in their current positions through Jan. 2, Graham added.

“They were hired for a specific job, and that is nearing completion,” Graham said.

Asked if Trimeris would hire permanent replacements for those positions, Graham replied: “Right now, the board is looking at all opportunities to add shareholder value. They are confident we have the management team in place that is capable of executing our strategy.”

Trimeris has “spoken” with HealthCor about the letter that it submitted to the board, he added. “But we’re not elaborating more than that,” Graham said. “Nothing has changed.”

HealthCor disclosed in the filing that it had purchased an additional 54,410 shares at a price of $7.78 per share. It purchased nearly 480,000 shares in September and some 290,000 shares in August, according to data from Thomson Financial.

Trimeris shares traded at $7.63 Thursday afternoon.

In the filing, HealthCor said it would continue to explore “various strategies for maximizing shareholder value” such as the sale of the firm or “certain of its assets.”

Hill, the interim president and chief operating officer, and Ratto, the interim chief financial officer, notified the company that they would terminate their agreements. The notice was filed through the consulting firm Hickey and Hill, where both men are consultants.

In August, the men signed agreements with Trimeris that extended their tenure through Dec. 31, 2008.

Hill is being paid an hourly rate of $450. Ratto receives an hourly rate of $380.

If Hill’s agreement had been terminated before Dec. 31 of this year he would have received no less than 90 days of estimated fees, according to the agreement signed in August.

Dani Bolognesi, one of Trimeris’ co-founders, was asked to resign as CEO by the Trimeris board in March. Robert Bonzcek, the CFO, also was asked to step down.