Complex sentence: Alovudine (fluorothymidine) was an antiviral agent being developed by Medivir, which was discontinued after a Phase II trial in 2005 due to toxicity.
Split into simpler sentences: Alovudine (fluorothymidine) is an antiviral agent which was being developed by Medivir. It was discontinued after a Phase II trial in 2005 due to toxicity.