Oct 6 (Reuters) - Amgen said on Friday it had completed the $27.8 billion acquisition of Horizon Therapeutics after it received the go-ahead from the U.S. Federal Trade Commission (FTC) last month on certain conditions.

Under the settlement terms with the FTC following its lawsuit to block the deal, Amgen is prevented from using anticompetitive tactics to extend the market dominance of Horizon's thyroid eye disease treatment Tepezza and gout drug Krystexxa.

The FTC's antitrust lawsuit had raised concerns over increased oversight on mergers and acquisitions in a sector that often turns to consolidation to power future growth as patents on older treatments expire.

The deal

closure

was within the fourth-quarter timeline set by the two companies. (Reporting by Mariam Sunny in Bengaluru; Editing by Anil D'Silva)