US regulators have upheld a prior decision rejecting Hikma and Vectura’s generic formulation of GlaxoSmithKline's asthma and chronic obstructive pulmonary syndrome therapy Advair Diskus.

The groups initiated the US Food and Drug Administration’s dispute resolution process over the regulator’s request for an additional clinical endpoint study, having addressed all other queries outlined in the Complete Response Letter issued last May.

The FDA has now concluded the dispute process and has upheld the previous call for the extra study, further delaying the drug’s potential launch date.

In anticipation of this as one of the potential outcomes, Hikma said it has already finalised the planning of a new clinical study and expects to start patient enrolment in the coming weeks, with a view to submitting a response to the FDA with new clinical data as early as possible in 2019.

“Whilst the outcome of the dispute resolution process is disappointing, we now have a clear pathway forwards, and we and our partner Hikma remain confident in, and committed to the approval of VR315,” said Vectura’s chief executive James Ward-Lilley.

“Assuming the successful execution of the new study and a standard regulatory review, we now expect a potential approval and launch during 2020.”