NEW YORK (CNNMoney.com) -- ImClone executive Alexander Denner said Wednesday that looking for a new CEO with strong biotech experience was the company's most important challenge - but he didn't name names or estimate how long the search would take.

"Finding the right CEO, one with meaningful biotechnology experience, is top priority for the board," said Denner in a conference call with analysts. "We do have a number of people identified and we'll be moving forward as soon as possible. We're beyond the first stages of the search."

Denner is the newly-appointed chair of the ImClone Systems (up $0.61 to $30.05, Charts) executive committee.

ImClone has had no chief since Tuesday, when its interim CEO Joseph Fischer resigned at the behest of billionaire Carl Icahn, who holds a 14-percent stake in the company. Icahn, who also forced out two other board members, was named chairman of the board on Wednesday, the same day that ImClone reported a surge in third-quarter net income. (Icahn had previously headed the committee that's looking for a new CEO.)

"We're disappointed that we don't have a new CEO right now, today, but it will take some time," said Denner, when an analyst asked if he would be "disappointed" if he couldn't find a new CEO within three or four months. "We don't know how long it will take."

Denner also said that ImClone wanted to "evaluate" its relationship with marketing partner Bristol-Myers Squibb (down $0.22 to $24.53, Charts) on the biotech's sole drug Erbitux, a treatment for colorectal and head and neck cancer.

"We believe that more can be done to optimize Erbitux," said Denner, without providing details, except to say that the company had no intention of severing its Erbitux partnership with Bristol-Myers, which is slated to last until 2017.

So far, Erbitux sales have been growing quickly. ImClone said third-quarter U.S. net sales of Erbitux soared to $175 million, up from $107 million during the same period last year.

But some analysts are concerned about future Erbitux sales, given the Food and Drug Administration's recent approval of Vectibix, a treatment for head and neck cancer from Amgen (up $0.24 to $75.18, Charts), the biggest biotech in the world. Vectibix could begin competing with Erbitux in the fourth quarter.

Bristol-Myers, the fifth-largest U.S. drugmaker, is scheduled to report earnings Thursday. Like ImClone, Bristol has recently undergone major changes at its highest levels of management. Bristol's former CEO Peter Dolan was forced out and the company is currently headed by interim CEO James Cornelius.

Six reasons why ImClone is a risky investment