(Reuters) – Celltrion Pharm Inc’s biosimilar of Roche Holding AG’s blockbuster cancer drug, Rituxan, on Wednesday won unanimous backing from an advisory panel to the U.S. Food and Drug Administration.

The tussles in the biosimilars market are a growing focus for investors, with soaring valuations for some pioneers in the field, including Celltrion, and worries about the long-term sales threat to makers of the original drugs such as Roche and AbbVie.

The vote comes after FDA staff reviewers https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/OncologicDrugsAdvisoryCommittee/UCM622649.pdf said Celltrion’s biosimilar, CT-P10, was highly similar to Rituxan. The agency usually, but not always, follows the advice of its advisory panels.

The FDA had in February declined to approve https://www.celltrion.com/en/pr/newsDetail.do?seq=482 the copycat drug, citing issues related to certain manufacturing process at Celltrion’s facility.

Celltrion has partnered with Israel’s Teva Pharmaceutical Industries Ltd to commercialize CT-P10 in the United States and Canada.

Biological drugs such as Rituxan are complex molecules made inside living cells, which means rivals looking to make copies when patents expire can only produce medicines similar to the original rather than identical.

Switzerland-based Roche, the world’s biggest producer of cancer drugs, is stepping up cost cuts in an efficiency drive made unavoidable by competition from cut-price biosimilars of its three best-selling drugs Rituxan, Herceptin and Avastin.

Rituxan brought in sales of $3.53 billion in the first half of 2018, a 9 percent drop from a year earlier, mainly due to the launch of biosimilars in most EU markets.

(Reporting by Ankur Banerjee in Bengaluru; Editing by Shailesh Kuber and Sriraj Kalluvila)