Complex sentence: Entecavir is a guanine analogue that inhibits reverse transcription, DNA replication and transcription in the viral replication process, and the manufacturer claims that it is more efficacious than previous agents used to treat hepatitis B (lamivudine and adefovir).
Split into simpler sentences: Entecavir is a guanine analogue that inhibits reverse transcription, DNA replication and transcription in the viral replication process. The drug's manufacturer claims that entecavir is more efficacious than previous agents used to treat hepatitis B (lamivudine and adefovir).