MannKind Corp. in Westlake Village has received its final $12.5 million milestone payment from United Therapeutics, the company said Thursday.

The development milestone is fourth in a line of payments stemming from a licensing and collaboration agreement to develop and commercialize a dry inhalable powder formulation of treprostinil.


Treprostinil Technosphere, or TreT, is currently being tested to treat pulmonary arterial hypertension. MannKind’s TreT studies have reached a point where regulatory filing is in sight, the companies said.


“We are looking forward to working with United Therapeutics during the first part of 2021 to prepare an FDA submission for TreT,” Michael Castagna, chief executive of MannKind, said in a statement.


MannKind will receive low double-digit royalties on net sales of TreT and will manufacture supplies of TreT; the company will earn a manufacturing margin as well.


Shares of MannKind (MNKD) closed Friday up 14 cents, or 5 percent, to $2.90 on the Nasdaq.