A new fungal treatment developed by Novartis has been rejected by the European Union’s Committee for Medicinal Products for Human Use on the grounds that its safety has not been proven and questions still remain about the manufacturing quality of the product.

Novartis had sought approval to sell the drug, called Mycograb (efungumab), alongside amphotericin B to treat patients with invasive candidiasis. Because the number of patients with invasive fungal infections is low, Mycograb was designated an orphan medicine.

Mycograb was developed by UK biotech firm Neutec, which Novartis acquired in June for around $575 million, saying that Mycograb was the primary reason for the transaction as it was aimed at expanding its portfolio of compounds for hospital-acquired fungal and bacterial infections.

In a statement, the CHMP said it was “concerned about some aspects of the quality of the medicine, such as the way the molecules of efungumab may fold or aggregate in the solution for injection and the level of some substances that could stimulate an immune response in patients.”

Novartis noted that Mycograb is a complex biological product produced through microbial fermentation and is produced by third party manufacturers, and that it aims to provide ‘clarification and analyses’ that should help it secure approval.

It also had concerns about the safety of Mycograb, particularly because the drug associated with cytokine release syndrome, a condition that can cause nausea, vomiting, pain and also high blood pressure. The reason for this is not clear, said the CHMP, and it concluded that too few patients have received Mycograb for its safety to be sufficiently assessed.

Novartis said it now plans to provide the European Medicines Agency (EMEA) with additional data to support the safety profile of the drug, but would not speculate on a timeframe for securing approval.

Mycograb was filed with the European regulatory authorities in March last year, with a US submission anticipated in 2009.