The US Food and Drug Administration has rejected Vernalis’ cough cold treatment CCP-07, which is being developed by US partner Tris Pharma.

The regulator issued a complete response letter outlining questions that must be addressed before approval is considered, though did not raise any concerns with the formulation or pharmacokinetic profile of the drug, Vernalis stressed.

“We remain committed to the approval of CCP-07 and will work closely with the FDA to resubmit the NDA as quickly as possible" said Ian Garland, the firm’s chief executive.

Tris is developing up to six unique extended release equivalents to existing immediate release prescription cough cold treatments for the US market under an exclusive licensing and collaboration agreement signed with Vernalis back in February 2012.

CCP-07 is the second product from this pipeline to be accepted for full NDA review following Tuzistra, which was approved by the FDA and subsequently launched by Vernalis in 2015.

Meanwhile, in better news for the firm, Vernalis confirmed that it has received a $2 million milestone under one of its existing research collaborations to discover novel small molecules against an undisclosed target utilising its fragment and structure-based drug discovery platform.

Further details were not given.