InSite Vision (INSV) announced that Merck (MRK), through its subsidiary Inspire Pharmaceuticals, has agreed to amend the payment terms of the existing AzaSite 1% license agreement. On a quarterly basis, Merck will pay InSite the higher of the pro-rata annual minimum royalty or the earned royalty for 2012 and 2013. In addition, in August 2012, Merck will pay InSite a catch-up payment for the difference between the earned royalty already paid for the fourth quarter of 2011 and the first and second quarters of 2012, and the pro-rata annual minimum royalties for those quarters. Under the terms of the AzaSite license agreement, the minimum royalties due to InSite in 2012 total $17M. InSite expects to receive minimum royalties of $4.25M for the fourth quarter of 2012. In addition, Merck will pay InSite a catch-up payment of about $7.2M before August 15, 2012.