Theseus lays off almost three-fourths of its staff

A view of Cambridge looking toward Kendall Square. Theseus Pharmaceuticals is the latest biopharma firm in Massachusetts to slash its workforce in a prolonged industrywide shakeout.David L. Ryan/Globe Staff

Theseus Pharmaceuticals says it is laying off 72 percent of its workforce, or 26 employees, just four months after safety concerns derailed the Cambridge biotech’s clinical trial on an experimental drug to treat a form of gastrointestinal cancer.

Theseus announced the layoffs after the market closed Monday and said it was “exploring strategic alternatives to maximize shareholder value,” corporate lingo for launching a sale.

It is the latest biopharma firm in Massachusetts to slash its workforce in a prolonged industrywide shakeout that followed years of exuberant — some say too exuberant — investment and growth.

Among those getting the ax was the firm’s president of research and development, William C. Shakespeare. He will serve as a consultant to Theseus until June 30 of next year.

The firm said in a news release that it was considering a “wide range of options,” including a “potential sale of assets of the company, a sale of the company, a merger or other strategic action.” As of Sept. 30, Theseus had cash and marketable securities of $225.4 million.

Theseus was working on targeted therapies for cancer. But it pulled the plug on a closely watched clinical trial in July for a gastrointestinal stromal tumor treatment amid concerns about the possible toxicity of the drug at certain doses.

The company went public in 2021, selling 10 million shares at $16 each and raising $160 million in what was considered a successful stock market debut. That was $60 million more than the firm had planned when it filed papers for the initial public offering.