Theravance has had a mixed response from advisors at the US Food and Drug Administration in a bid to expand the label on its superbug antibiotic Vibativ.

The company is trying to get approval  for Vibativ (telavancin) for the treatment of nosocomial pneumonia (NP, also known as hospital-acquired pneumonia). The once-a-day injectable antibiotic was approved in the USA in 2009 for adults with complicated skin and skin structure infections (cSSSI) caused by susceptible Gram-positive bacteria, but the path to getting the green light for NP across the Atlantic has been rough; Vibativ is approved in Europe in September 2011 for adults with NP caused by methicillin-resistant Staphylococcus aureus (MRSA) when other alternatives are not suitable.

The FDA's Anti-Infective Drugs Advisory Committee was asked to consider analyses of clinical cure and 28-day all-cause mortality and voted 6- 9 that the results provide substantial evidence of the safety and effectiveness of Vibativ for NP. However, the panel voted 13- 2 in favour when other alternatives are not suitable.

Theravance chief executive Rick Winnigham said "we are pleased that the advisory committee believes there is a role for Vibativ in the treatment of NP, a serious disease that causes significant morbidity and mortality, particularly given rising microbial resistance to existing therapies".

The panel raised serious concerns about the drug's toxic effect on the kidneys but chair of the FDA committee chair, Thomas Moore of the University of Kansas School of Medicine in Wichita, told MedPage Today that doctors could use Vibativ as an additional tool "even through it has less than ideal safety profile".

He voted against Vibativ in the 6-9 decision but added that "it's a drug that shouldn't be ruled out completely" and one that "we should just use in limited situations".