BOULDER — Array BioPharma Inc. (Nasdaq: ARRY), a Boulder-based commercial-stage pharmaceutical that focuses on cancer treatments, will be acquired by pharmaceutical giant Pfizer Inc. (NYSE: PFE) in a deal estimated to be worth about $11 billion.

Under the terms of the agreement, which has been approved by both companies’ boards of directors, Pfizer will pay $48 in cash for each Array share.

“Today’s announcement reinforces our commitment to deploy our capital to bring breakthroughs that change patients’ lives while creating shareholder value,” Pfizer CEO Albert Bourla said in a prepared statement. “The proposed acquisition of Array strengthens our innovative biopharmaceutical business, is expected to enhance its long-term growth trajectory, and sets the stage to create a potentially industry-leading franchise for colorectal cancer alongside Pfizer’s existing expertise in breast and prostate cancers.”

Pfizer says it plans to keep Array’s workforce on board at operations in Boulder; Cambridge, Massachusetts; and Morrisville, North Carolina.

Array’s Boulder laboratory operations will be maintained and folded into Pfizer’s Oncology Research and Development network, which includes operations in La Jolla, California, and Pearl River, New York.

The transaction is expected to be completed later this year.

“We are incredibly proud that Pfizer has recognized the value Array has brought to patients and our remarkable legacy discovering and advancing molecules with great potential to impact and extend the lives of patients in critical need,” Array CEO Ron Squarer said in a statement. “Pfizer shares our commitment to patients and a passion for advancing science to develop even more options for individuals with unmet needs. We’re excited our team will have access to world-class resources and a broader research platform to continue this critical work.”

News of the acquisition sent Array’s stock price skyrocketing in early Monday trading. As of just after 10 a.m., the company’s stock price was $46.11, up nearly 56 percent on the day.