THOUSAND OAKS, Calif. (AP) — Biotech drugmaker Amgen said Monday that it plans to buy back up to $5 billion of its stock in a modified Dutch auction tender offer.

The Thousand Oaks, Calif., company says it will purchase the shares for between $54 and $60 each.

The modified Dutch auction tender offer allows shareholders to state the amount of shares they wish to tender and the price they are willing to pay within the company's range. Amgen then will determine the lowest per-share price that enables it to buy $5 billion in stock.

It will pay the same price for all shares purchased in the offer, so it may buy some stock at a higher price than the shareholder indicated. But the company said it will not make purchases below a price indicated by a stockholder.

"Our strong balance sheet and cash flow enable us to complete this transaction in an attractive interest rate environment while also preserving the flexibility to further accelerate the growth of our business through focused, strategic acquisitions," Chairman and CEO Kevin W. Sharer said in a statement.

Amgen Inc. will hold a public offering of senior notes to help pay for the tender offer. BofA Merrill Lynch, Morgan Stanley, J.P. Morgan and Citigroup are acting as joint book-running managers for the offering.

Company shares climbed $3.12, or 5.7 percent, to $58.78 in morning trading Monday.