A dozen Pacific nations closed in on a sweeping free trade pact on Sunday in Atlanta after a breakthrough over how long a monopoly pharmaceutical companies should be given on new biotech drugs.

The issue has pitted the United States, which has argued for longer protections, against Australia and five other delegations who say such measures would strain national healthcare budgets and keep life-saving medicines from patients who cannot afford them.

The compromise would preserve Australia's existing five-year protection period but would also offer flexibility on longer drug monopolies, potentially creating two tracks on future drug pricing within the trading bloc, a person close to the negotiations said.