MannKind Corp. has appointed Dr. Michael E. Castagna as its new chief commercial officer, effective immediately, the company announced Monday. In his new position, Castagna will spearhead commercialization of Afrezza, an inhalable insulin that is currently the Valencia biotech’s sole commercial product. Castagna will report directly to Chief Executive Matthew Pfeffer and will be part of the company’s executive leadership team. Prior to joining MannKind, Castagna was vice president of global lifecycle management for Amgen Inc. in Thousand Oaks. He has more than 20 years of experience in the health care industry and has worked for pharmaceutical heavyweights such as Sandoz, owned by Swiss drug maker Novartis. “I am excited to be joining MannKind at this critical intersection as we transform our future,” Castagna said in a statement. “I am enthusiastic about the commercial opportunity for Afrezza and the potential it has to help adults with diabetes.” In addition, MannKind also announced that Juergen A. Martens has resigned as chief operating officer, effective Friday. MannKind shares closed up 6 cents, or 4.5 percent, to $1.39 on the Nasdaq.