Sirion Therapeutics has received the US FDA has approved its NDA for Zirgan(TM) (ganciclovir ophthalmic gel) 0.15% as a treatment for acute herpetic keratitis (dendritic ulcers). The FDA approval was based on the results of clinical trials conducted by Laboratoires Thea of France in Europe, Asia and Africa that compared the efficacy and tolerability of Zirgan to acyclovir ophthalmic ointment 3% in patients with herpetic keratitis.