By Johanna Urbancik

The United States has launched a trade investigation into Germany's drug pricing policies.

Washington says it wants to examine whether innovative medicines are undervalued in Germany, leaving US patients to shoulder a disproportionate share of pharmaceutical research and development costs.

The announcement was made on Thursday in a statement by US Trade Representative Jamieson Greer, who said the investigation would determine whether Germany's "persistent underpayment for innovative pharmaceutical products by Germany is unreasonable or discriminatory and burdens or restricts US commerce."

The investigation follows months of discussions between Washington and Berlin aimed at resolving the dispute.