The European Commission has granted orphan drug designation to Maribavir,ViroPharma Inc.’s experimental treatment of cytomegaloviral disease in patients with impaired immune systems.

The designation is another step in the resurrection of Maribavir, a drug the Exton, Pa., biopharmaceutical company had put on the shelf in 2009 after disappointing clinical trials results testing the drug’s ability to prevent cytomegalovirus (CMV) infections in transplant recipients.

Last year, I wrote about how the company was giving the new drug candidate a second lookafter doctors at transplant centers in France had success in tests using the drug to treat such infections in patients after they underwent transplant procedures. ViroPharma licensed the rights to the drug from GlaxoSmithKline (NYSE: GSK) in 2003.

The cytomegalovirus is a member of the herpes virus group, which includes the viruses that cause chicken pox, mononucleosis, cold sores and genital herpes. Like other herpes viruses, CMV has the ability to remain dormant in the body for long periods of time.

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