The U.S. Food and Drug Administration has approved Trazimera, Pfizer Inc.'s biosimilar to Roche Holding AG's breast cancer drug Herceptin.

In 2018, the U.S. regulator chose not to approve Trazimera, requesting additional technical information from the New York drugmaker, although concerns at the time were not based on safety or clinical data in the application.

The FDA has approved three prior Herceptin biosimilars: the first from Mylan NV at the end of 2017, one from Celltrion Inc. and the most recent from Samsung Bioepis Co. Ltd. in January.

In Europe, where Trazimera became the first-ever cancer biosimilar in July 2018, sales of Herceptin were 16% lower than the previous year due to the competition, Switzerland's Roche reported in its 2018 earnings report.

Roche CEO Severin Schwan said at the time that the company is anticipating biosimilar competition to affect sales in the U.S. in the second half of 2019.

The biosimilar approval comes just over a week since the FDA approved Roche's own new formulation of the drug. The new one employs a drug delivery technology that allows it to be injected under the skin in five minutes compared to the 30 minutes to 90 minutes required for a Herceptin dose.

Trazimera is the 18th FDA-approved biosimilar in four years.