(Reuters) - U.S. generics drugmaker Mylan said on Thursday that the United States Patent and Trademark Office had rejected Sanofi’s infringement claims relating to insulin drug Lantus.

FILE PHOTO: The logo of Sanofi is pictured during the Viva Tech start-up and technology summit in Paris, France, May 25, 2018. REUTERS/Charles Platiau

Sanofi is heavily reliant on Lantus, its leading product with sales of 4.62 billion euros ($5.26 billion) in 2017, and Mylan’s own insulin drug would be its second competitor after Eli Lilly launched its version in late 2016.

Lantus is a long-acting insulin used to treat adults with type 2 diabetes and adults and paediatric patients with type 1 diabetes to control high blood sugar.

Sanofi, which settled a similar case with Lilly in 2016, allowing it to launch Basaglar, sued Mylan in October 2017.

Shares in Sanofi, whose diabetes revenues have fallen since 2015, as Lantus is squeezed by pricing pressure, fell 1 percent on the Mylan announcement, although the French group said its U.S. rival would not be able to launch its insulin drug.

“We believe that it is unlikely that the Patent Trial and Appeal Board (PTAB) ruling on the formulation patents will have an impact on Mylan’s timing for a launch of its glargine products,” a Sanofi spokesman said in an emailed statement.

“The PTAB decision alone does not affect the existing 30-month stay and Mylan does not have tentative Food and Drug Administration approval for its products at this time.”

Mylan was not immediately available for comment.

The 2017 case, which includes some patents covering a disposable injection pen version, Lantus SoloSTAR, is pending and no trial date has been set, Mylan said.

Separately, Mylan’s generic versions of Lantus and Lantus SoloSTAR, developed with India’s Biocon, are being reviewed by the FDA.