TEL AVIV, July 3 (Reuters) - Teva Pharmaceutical Industries has filed a so-called citizen petition with the U.S. Food and Drug Administration (FDA), aiming to delay cheap generic competition to Copaxone, its top-selling treatment for multiple sclerosis (MS).

In the citizen petition process, the FDA reviews the petition and can decide to delay the approval of the relevant drug, according to the FDA website.

Israel-based Teva, which makes about 20 percent of its sales and about half of its profit from Copaxone, said on Thursday it had submitted the petition "in accordance with the agency's desire to facilitate public review and comment regarding new scientific data on gene expression".

Its data show "it would be contrary to the public's health and welfare to approve a purported generic glatiramer acetate (Copaxone) product that ... at best can be shown to be similar, but clearly not the same as, Copaxone," Teva said.

Teva's position is that any potential generic version of Copaxone be evaluated via full-scale, placebo-controlled clinical trials in patients with relapsing forms of multiple sclerosis to establish safety and efficacy.

Copaxone, an injectable drug, faces competition from oral treatments as well as cheaper generics in the coming years.

The U.S. Supreme Court will hear arguments in Teva's appeal in a Copaxone patent fight in the autumn and a ruling is expected in 2015.

In the meantime, the court denied Teva's request to reverse a ruling from a lower court in favour of two teams of rivals working on generics - Novartis AG's Sandoz Inc and Momenta Pharmaceuticals Inc, as well as Mylan Inc and Natco Pharma Ltd.

(Reporting by Tova Cohen; Editing by Mark Potter)