Shares of Brentwood biotech firm CytRx Corp. tumbled Tuesday after the company announced it would price a forthcoming public offering of 9.1 million shares of common stock at $2.75 a share, well below where shares have been trading for most of the year.

CytRx shares closed Tuesday at $3.04, down 20 percent on the day.

That’s a much bigger loss than the stock saw on Monday, when the firm first announced the offering. Shares dropped 4.3 percent that day, closing at $3.80. The drug developer’s stock has traded above $3.00 for most of this year.

CytRx, which specializes in the development of oncology therapies, said it plans to use offering proceeds of about $25 million to fund clinical trials of its drug candidate aldoxorubicin, which binds to popular chemotherapy drug doxorubicin aiming to improve that therapy while minimizing its side effects.

The firm also plans to use the proceeds for drug discovery and general corporate purposes.

CytRx brought in just $100,000 in licensing revenue last year and took a net loss of $30.1 million, mostly due to research and development expenses. Executives said they could not comment until the offering closes, which is expected Friday.