Image caption Madonna's lawyers claim the singer 'is the Material Girl'

A US judge has denied a request to throw out a legal case involving Madonna's Material Girl clothes line.

Retailer LA Triumph sued the singer's company last year, claiming it had been selling a range with the same name since 1997 and owned the trademark.

Madonna's lawyers argued she was a "senior user" of the trademark, having made it famous in her 1985 hit song.

Federal judge James Otero disagreed, and ordered that the dispute should proceed to trial.

"The singing of a song does not create a trademark," he wrote, adding that the defendants' argument "fails as a matter of law".

Madonna did not write Material Girl, which featured on her breakthrough Like A Virgin album, but the moniker has stuck with her over the years.

She has often hinted that she regrets releasing the song, as its message is at odds with her preferred image of a strong, independent woman.

And when she performed the single during her Blond Ambition tour in 1990, the star adopted a nasal "valley girl" accent to poke fun at the shallow lyrics.

Nonetheless, court documents show that Madonna's company, MG Icon, argued that "Madonna is the Material Girl".

Lawyers added that $85m (£53.2m) worth of merchandise bearing the phrase had been sold at concerts, proving that Madonna had used the trademark first.

LA Triumph countered that it only proved the phrase had been used for merchandising and not clothing.

The judge denied MG Icon's request for a summary judgment, and said he would allow the jury to hear evidence about the issue at the trial.

If the clothing retailer is successful, Madonna could be forced to change the name of her clothing line.

The range - which she launched last year with her daughter Lourdes - currently sells in US store Macy's, which is also named as a co-defendant in the case.

The trial is expected to begin in October.