SAN DIEGO ( TheStreet) -- 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.