FDA Declines to Approve Targanta Antibiotic

Updated from 1:07 p.m. EST

Targanta Therapeutics(TARG Quote) said Tuesday that the U.S. drug regulators decided not to approve the company's injectable antiobiotic oritavancin until an additional clinical study is performed.

The U.S. Food and Drug Administration's rejection of oritavancin isn't a complete surprise. In late November, an FDA advisory panel voted 10-8 against recommending approval. That decision sent Targanta shares sliding more than 80%.

Targanta shares closed Tuesday at $1.34, down 40.44% from Monday's close of $2.25.

The Cambridge, Mass.-based drugmaker had been seeking approval for oritavancin to treat skin infections caused by antiobiotic-resistant superbugs like methicillin-resistant Staphylococcus aureus (MRSA).

In its complete response letter to Targanta, the FDA asked for another clinical study that would demonstrate oritavancin's efficacy in patients diagnosed with MRSA, according to the company.

The FDA determined that the two clinical trials submitted by the company weren't sufficient for approval, the company said. The FDA was also concerned about several safety findings from those two studies.

Oritavancin was originally developed by Eli Lilly(LLY Quote) and was acquired by InterMune(ITMN Quote) in 2001. Targanta gained rights to the drug in 2005.

Last month's FDA advisory panel meeting, in addition to voting against oritavancin, also recommend the approval of a competing antibiotic from Theravance(THRX Quote). That drug, telavancin, is stll being reviewed by the FDA.