GlaxoSmithKline has returned the rights to an investigational inflammatory bowel disease drug to the USA’s ChemoCentryx.

The drug in question is vercirnon, an inhibitor of the chemokine receptor known as CCR9. Last month, GSK published data from the first of four Phase III studies in patients with moderately-to-severely active Crohn’s disease which showed that the drug did not achieve the primary endpoint of improvement in response and the key secondary endpoint of remission.

Noting that “there was a trend for dose-dependent increases in overall adverse event rates”, new recruitment and dosing in the ongoing clinical programme was suspended pending further review of the results. Now, following the results from the 608-patient trial, GSK has decided not to continue.

On the other hand, it seems as though ChemoCentryx has not given up on vercirnon yet, on the basis of a 436-patient Phase II study it has conducted that differed from the approach GSK was taking and involved a lower dose and less ill patients.   

Chief executive Thomas Schall said "we are pleased to have a response from GSK which gives us certainty that vercirnon now returns entirely to ChemoCentryx, and which confers to us many degrees of freedom in deciding this valuable asset's forward path”. He added that importantly, the full data set amassed on all the trials (whether concluded or not) will be transferred, which “will allow us to assess, alone or potentially with a partner, a remaining, critical clinical trial question: that is, whether the drug maintains remission in Crohn's disease”, as seen in the maintenance phase of the aforementioned ChemoCentryx study”.

The companies have been partners since August 2006 after signing a four-drug pact. One was dropped in February and now vercirnon has gone, but GSK is still involved in developing the other two: a CCR1 inhibitor for rheumatoid arthritis for which GSK exercised its option for an exclusive licence in 2011 and CCX168, an inhibitor of the complement receptor C5a, currently in Phase II for ANCA vasculitis.