(Reuters) - After deliberating for most of the year, Isis Pharmaceuticals Inc said on Friday it would change its name to avoid being confused with the Islamist militant group known as ISIS.

The biotechnology company said it would be called Ionis Pharmaceuticals Inc from Dec. 22 and also changed its stock exchange ticker symbol to "IONS" from "ISIS".

"It's been an ongoing discussion for most of this year", Chief Business Officer Sarah Boyce told Reuters.

"When you talk about the company you want people to immediately think about the incredible work you're doing to deliver transformational drugs to patients ... not as an unfortunate namesake."

The Carlsbad, California-based company's stock dropped about 4 percent on the first trading day after the Paris attacks, for which ISIS claimed responsibility.

The drugmaker - named after the Egyptian goddess Isis, who was revered as a protector and healer - has been around for more than a quarter century.

Today it is a $7 billion company with one cholesterol drug on the market and treatments in development for a plethora of diseases, including cancer and heart conditions.

(Corrects to delete extraneous words in paragraph 6.)

(Reporting by Natalie Grover in Bengaluru; Editing by Savio D'Souza and Ted Kerr)