FILE PHOTO: Roche tablets are seen positioned in front of a displayed Roche logo in this photo illustration January 22, 2016. REUTERS/Dado Ruvic/Illustration/

WASHINGTON (Reuters) - The Federal Trade Commission staff reviewing Roche's RBO.PA plan to buy U.S.-based gene therapy specialist Spark Therapeutics ONCE.O for $4.3 billion recommended that the deal be approved without requiring any asset sales, the Capitol Forum reported on Thursday.

Basel-based Roche, the biggest maker of cancer drugs, said in February that it would buy the U.S. company, acquiring a portfolio that includes a blindness treatment that has U.S. and European approval and other projects for neurodegenerative disorders like Huntington’s disease. One of its projects is a gene therapy treatment for hemophilia.

The FTC staff had focused on hemophilia treatments since Roche markets Hemlibra, the report said.

Following the staff’s recommendation, officials at the top of the FTC’s Bureau of Competition must weigh in. The next step would be a vote by the FTC chairman and four commissioners.

The deal must also win approval from the UK’s Competition and Markets Authority, which said this week that it had a deadline of mid-December for a Phase 1 decision. A Phase 2 probe would be more in-depth and detailed.

Roche, Spark and the FTC all declined comment.