Novartis AG stopped development of its Aurograb treatment for bacterial infections after it showed a lack of efficacy in mid-stage trials, and said it would take a $235 million impairment charge.

Novartis acquired Aurograb, which was being assessed for treating methicillin-resistant staphylococcus aureus (MRSA), in 2006 when it bought NeuTec Pharma, a specialist in fighting hospital superbugs, for nearly $570 million. That represented a premium of 109 percent to NeuTec's prior share pice, highlighting big pharmaceutical companies' drive to snap up biotechnology assets. Another compound acquired with NeuTec, Mycograb, continues in late-stage trials for the treatment of invasive candidiasis, a life-threatening fungal infection.