EntreMed Inc. has renegotiated a $3.3 million obligation to drugmaker Bristol-Myers Squibb Co., giving the cash-starved biotechnology company some breathing room while it searches for a last-ditch investment to fund operations.

The Rockville company, which is clinging to its final three weeks of cash, said yesterday that it will buy back about 292,000 shares from Bristol-Myers -- as required under a 1995 agreement -- but will make payments "now and over a future period of time." Amy Finan, EntreMed's spokeswoman, declined to comment further on the revised agreement.

Analysts said it appears that EntreMed struck a deal to avoid spending more than half of its remaining cash reserves, estimated at less than $4.8 million, on stock when the company is fighting for its life. Under the earlier agreement, EntreMed was required to purchase the stock at $13.14 per share.

The company is trying to renegotiate a number of its financial liabilities to corporate partners, service providers and vendors, Chief Operating Officer Neil J. Campbell said in a statement. EntreMed reported in September that its cash would run out by Jan. 1. Without a major public or private financing, the company said in filings with the Securities and Exchange Commission, "we will have to cease and/or curtail our operations or seek protection under U.S. bankruptcy laws."

EntreMed is already hunkering down. In the past year it has laid off half its staff, postponed tests on its leading drug candidates and asked executives to defer a portion of their salaries. John W. Holaday, chief scientific officer, has said the company is searching for a financial deal favorable to existing shareholders.