MannKind Corp., a developer of therapies for diabetes and cancer, on Thursday said it plans a public sale of 20 million common shares priced at $17.42 apiece.

Also, MannKind has agreed to sell $100 million aggregate principal amount of 3.75 percent senior convertible notes due 2013 in an underwritten public offering. The underwriters have a 13-day option to purchase up to $15 million in additional notes to cover overallotments.

Certain officers and directors, including the company's principal stockholder, Chairman and Chief Executive Alfred E. Mann, will purchase about 5.8 million shares in the offering. The underwriters have a 30-day option to buy up to another 3 million shares to cover overallotments.

JPMorgan Securities Inc. and Merrill Lynch & Co. are the joint lead managers and joint bookrunners of both offerings.

MannKind shares rose 39 cents, or 2.2 percent, in premarket activity. The stock closed at $17.42 Wednesday on the Nasdaq.