NEW YORK, Dec 20 (Reuters) - BioMarin reached a settlement with activist investor Elliott Investment Management where the biotechnology company will add three independent directors to its board and form a committee to review operations.

The new Strategic and Operating Review Committee will evaluate the company's business, strategy and operations, financial and capital allocation priorities, and long-term planning and priorities, the company said in a statement.

In November, Reuters reported that Elliott owns a stake in BioMarin and had been holding discussions with the company, valued at $18 billion, about possible changes.

Since Elliott's involvement became public on Nov. 7 and since the company announced a new CEO earlier in November, the stock price has climbed 22% and closed trading at $92.66 on Tuesday.

The agreement marks the second settlement Elliott, which oversees $60 billion in assets, reached this week.

Earlier on Tuesday, wireless tower owner Crown Castle averted a proxy fight with Elliott when it added two new directors, including one Elliott executive, only weeks after announcing that its CEO will leave next month.

At BioMarin, the company and hedge fund agreed on three industry and finance experts who have no direct ties to Elliott.

Dr. Athena Countouriotis, co-founder and CEO of Avenzo Therapeutics; Mark Enyedy, CEO of ImmunoGen; and Barbara Bodem, who worked in finance at several pharmaceutical companies, join the board on Dec. 27.

AbbVie is acquiring ImmunoGen.

The BioMarin board will temporarily expand to 15 directors before returning to 11 directors after next year's shareholder meeting, the company said.

The settlement comes less than two months after San Rafael, California-based BioMarin hired former Genentech CEO Alexander Hardy to replace Jean-Jacques Bienaime, who is retiring.

Before Elliott's involvement became public BioMarin's share price was off roughly 24% for the year as it grappled with slow progress in the launch of its hemophilia drug Roctavian. The poor share price performance had led some analysts to speculate about whether the company could become a takeover target. (Reporting by Svea Herbst-Bayliss; Editing by Lisa Shumaker)