MannKind Corp. announced on Monday that Alfred Mann, its chairman and founder, stepped down as chief executive on Jan. 9 and was replaced by Hakan Edstrom, the company’s president. Mann, 89, who founded the Valencia biotech in 1991, will transition to executive chairman, while Edstrom, 65, will retain his title as president, which he has held since the company’s founding. Edstrom, who also was the company’s chief operating officer, will relinquish that post to Juergen Martens, chief technology officer since 2005. According to a regulatory filing, Mann informed the board on Jan. 6 of his intent to step down on Jan. 9. Mann “intends to remain engaged with the company in business matters, including those relating to development and financing of MannKind’s future therapies” in his role as executive chairman, the company said in a statement. The leadership transition follows a $50 million milestone payment MannKind received last week from French pharmaceutical company Sanofi for the biotech’s Afrezza inhalable insulin. The drug was approved for domestic sales by the FDA in June. The Paris company is handling worldwide marketing of Afrezza under an agreement that could earn MannKind close to $300 million. MannKind, which received the milestone payment for its work setting up the manufacturing process for Afrezza, also is developing other drugs, including an immunotherapy treatment for various human cancers. “I am truly excited to lead MannKind at this critical juncture as the company anticipates the launch of its first therapy and looks to move ahead with other blockbuster therapies,” said Edstrom, previously an executive at Bausch & Lomb Inc. and Pharmacia Corp., in a statement. Mann, a long-time Los Angeles resident who now lives primarily in Las Vegas, still owns a Mulholland Drive home and continues to have a roughly 40 percent stake in MannKind, according to a regulatory filing. Shares closed down 27 cents, or nearly 5 percent, to $5.49 on the Nasdaq.