MannKind Corp. announced on Monday its fourth quarter and end of year financial results that fell far short of analyst expectations. The Valencia biotech reported a loss of $277 million (-66 cents a share) in the quarter ending Dec. 31, compared to a loss of $36.4 million (-9 cents) for the same period a year earlier. The company reported no revenue. Analyst estimates were -5 cents a share, according to Thomson Financial Network. For the entire year, MannKind’s net loss was $368 million (-91 cents) compared to $198 million (-51 cents) in 2014. During the fourth quarter, sales of Afrezza, the company’s only commercial product, remained low, which prompted Sanofi to return the rights of the drug to MannKind earlier this year, impacting the overall value of the company. “Our financial results for 2015 were not what we expected going into the year, but we are looking forward to the next 12 months with optimism and great excitement,” Chief Executive of MannKind Matthew Pfeffer said in a statement. “Afrezza will soon be back under our control, and we are all energized about the opportunity to launch a lean, focused commercial effort that highlights the differentiating qualities of our lead product.” Shares closed down 2 cents, or 1.4 percent, to $1.41 on the Nasdaq.