MannKind Corp. has completed the second of two additional trials requested by the Food and Drug Administration for its inhaled insulin pipeline product, the company said Monday.

The Valencia biopharmaceutical company said it has completed Phase III trials of the drug Afrezza in patients with Type II diabetes, and plans to release the data later this summer. The trial is the last major hurdle before the company can ask the FDA for approval of the product, which it first did in 2011.

The study looked at the safety and effectiveness of the drug as administered to patients with Type II diabetes by the MedTone inhaler, the first model tested by MannKind, and a newer version, the Dreamboat inhaler. Both were compared to traditional injected insulin.

Another study, which compared the three delivery methods in patients with Type I diabetes, was completed June 3.

The trials were done at the request of the FDA, which called for more research in 2011 after MannKind had completed testing with the MedTone but then introduced the newer inhaler. The drug could be used to treat adults with Type I and Type II diabetes.

The company went public in 2004 and has yet to introduce a drug to the market. Most income has come through secondary offerings and the backing of its founder, billionaire entrepreneur Alfred Mann.

In December, Mann converted more than $107 million debt owed to him by MannKind into 40 million shares and warrants to purchase another 30 million.

Shares of MannKind closed down 17 cents, or 2.2 percent, to $7.54 on the Nasdaq.