Shares of MannKind Corp. jumped more than 16 percent Tuesday after the Westlake Village biotech finalized a previously announced agreement with United Therapeutics Corp. to develop an inhalable drug to treat a form of hypertension. United Therapeutics will pay MannKind $45 million upfront and up to an additional $50 million if the company hits certain targets to develop a dry powder form of the drug treprostinil. The much-needed cash infusion comes after MannKind made several equity swaps this year to restructure its debt to creditors. Last month, the company reported a quarterly loss of $22.7 million; as of June 30, the company had cash and cash equivalents of $26.7 million. Shares of Conejo Valley biotech firms rebounded Tuesday after being hit hard last week. Sienna Biopharmaceuticals in Westlake Village gained more than 13 percent, while Atara Biotherapeutics Inc. in Newbury Park jumped nearly 8 percent and Amgen Inc. in Thousand Oaks rose around 3 percent. Shares of MannKind (MNKD) rose 27 cents, or 16 percent, on Tuesday to close at $1.92 on the Nasdaq.