VALENCIA, Calif. ( TheStreet) -- U.S. regulators have delayed the approval of an inhaled insulin drug and device from MannKind Corp. ( MNKD), the company said Monday.

The U.S. Food and Drug Administration asked MannKind to provide updated data on the safety and efficacy of its Afrezza device and additional information about the inhaler used to deliver the insulin to the lungs. The FDA, however, did not ask for new clinical trials, MannKind said in a statement.

MannKind shares fell 7% to $9.71 in early Monday trading.

The announcement of FDA's complete response letter for Afrezza comes two months past its original Jan. 16 approval decision deadline. In early January, MannKind said FDA requested more time for the Afrezza review, in part, to complete inspection of a European manufacturing facility that makes the device's insulin.

MannKind's statement Monday does not mention whether that inspection was completed.

"We are currently reviewing the Complete Response letter and fully expect that we will be able to respond to the FDA's requests in a timely manner," said MannKind CEO Alfred Mann.

MannKind is seeking FDA approval for Afrezza as a drug/device for the treatment of patients with Type 1 and Type 2 diabetes.

FDA Ok on Amylin Drug Safety

(Updated at 7:15 AM EDT)

U.S. regulators delayed the approval of a new long-acting diabetes drug from Amylin Pharmaceuticals ( AMLN) and Eli Lilly ( LLY) to finalize the medicine's label and to clarify manufacturing.

While the U.S. Food and Drug Administration failed to approve Bydureon (previously known as exenatide once-weekly) Friday, the agency did not ask Amylin and Lilly to conduct new clinical trials or to submit additional safety data.

Amylin said it would work quickly to submit a response to the FDA's questions in the next few weeks. The company added that concerns about its Ohio manufacturing facility raised by FDA during a December inspection have already been corrected.

"This is a significant step forward in our ability to bring this important therapy to patients," said Dr. Orville Kolterman, Amylin's senior vice president of research and development, in a statement.

Bydureon is a once-weekly formulation of the twice-daily injectable drug Byetta, currently marketed by Amylin and Lilly. Byetta sales total around $700 million, but the more convenient Bydureon is expected to bring in well over $1 billion in revenue and be a major growth driver for the companies, according to analysts.

The drug-delivery technology that enables Bydureon to be dosed so infrequently comes from Alkermes ( ALKS), which will receive royalties on sales of the drug when approved.

Bydureon and Novo Nordisk's ( NVO) recently approved Victoza belong to the GLP-1 class of injectable diabetes drugs intended to control blood sugar in Type 2 diabetes medicines. Victoza requires a once-daily injection.

Amylin shares closed Friday at $20.26; Alkermes shares closed at $12.21.

-- Reported by Adam Feuerstein in Boston.

Follow Adam Feuerstein on Twitter.

Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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