As challengers to Roche’s cancer blockbusters advance in the U.S. and around the world, Samsung Bioepis has taken a big step toward approval for a Herceptin biosim in Europe. A drug panel there recommended the proposed biosim, Ontruzant, creating a potential near-term threat to billions of Roche sales on the continent.

The European Medicines Agency’s Committee for Medicinal Products for Human Use recommended Samsung’s biosim in all reference indications: early breast cancer, metastatic breast cancer and metastatic gastric cancer. If ultimately approved by the European Commission, U.S. drug giant Merck would market Ontruzant in European countries.

Herceptin is among the world’s top selling drugs, bringing in around $7 billion last year for Switzerland’s Roche. In Europe, Herceptin generated more than $2 billion in 2016. In a statement, Samsung Bioepis CEO Christopher Hansung Ko said his company hopes Ontruzant can "play an important role expanding patient access to trastuzumab across the region" if it wins final approval.

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The recommendation comes as biosim developers race for a chance to eat away at Roche’s global cancer fortunes. On Thursday, Amgen and Allergan won U.S. approval for Mvasi, an Avastin biosim approved in each of the branded drug’s indications. Amgen and Allergan’s approval represents the first cancer biosim nod in the U.S. and a threat to $3 billion in Roche sales in the States.

The same biosim partners are also advancing a Herceptin biosim in the U.S. with competition from a Teva-plus-Celltrion collaboration. Back in July, the FDA accepted applications from both teams. Herceptin brought in more than $2.5 billion in the U.S. for Roche last year.

Marking a setback for one biosim team in Europe, Biocon and Mylan had to pull their Herceptin application last month due to manufacturing problems. They said they hope to resubmit the app yet this year. Pfizer also has a late-stage Herceptin biosim in the works.

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In a recent note, Bernstein analysts said that Herceptin biosim entry to the U.S. will be blocked by intellectual property barriers. In Europe, the analysts figure biosim makers will launch copies immediately after approval. Biosim developers could win European approval for multiple copycats by the end of next year, "setting this up to be a competitive market," the Bernstein team wrote in a recent industry snapshot.

Due to patent challenges and settlements, the analysts figure Herceptin biosim entry in the U.S. looks more likely at the end of 2018 or beginning of 2019.

To prepare for the biosim assault, Roche is looking to the next generation of therapies. On the company’s second-quarter conference call, CEO Severin Schwan said Roche has 16 breakthrough therapy designations at the FDA.

RELATED: Biocon pulls EU Herceptin biosim app but expects to return to the race next quarter

"This is industry leading and it's this kind of innovation, which will enable us to offset the entry of biosimilars, which we expect increasingly so over the next years," he told analysts.