VWR Corp. said it now expects to close its proposed merger with Avantor Inc. in the mid-to-late fourth quarter of 2017 to give the European Commission time to complete its review of the $6.4 billion deal.

Avantor is a global supplier of ultra-high-purity materials for the life sciences and advanced technology markets while VWR, which had sales in excess of $4.5 billion in 2016, provides product and service solutions to laboratory and production customers.

The deal was originally expected to close in the third quarter of 2017.