Skin regenerator Avita has been unrelenting in its legal case to cancel a competitor’s patent, but shareholders aren’t as confident.

Avita (ASX:AVH) brought the case against Renovacare earlier this year, claiming that the competitor’s US patent No. 9,610,430 was over technology that’s unpatentable and should be cancelled.

The patent in question covers a cell spraying device, the method and the sprayed cell suspension technology – all of which is critical to Avita’s “spray-on skin” therapy for burns and chronic wounds.

Shares in the company closed at 5.8c on Wednesday, down from 6.8c at the open.

By late morning on Thursday, however, it was back up 8.6 per cent to 6.3c.

The latest result in the case was handed down by the Patent Trial and Appeal Board (PTAB) in the US, denying Avita an Inter Partes Review.

This is a trial conducted by the PTAB to review the patentability of Renovacare’s technology.

But Avita says they aren’t budging.

“Avita continues to believe that all claims in the RenovaCare ‘430 patent are unpatentable,” chief executive Dr Mike Perry said.

“Avita will continue to assertively protect its intellectual property position and pursue all available options, including promptly filing a request for rehearing on the decision by the PTAB.”

In the last quarter the company made $381,000 from customers and had $726,000 left in the bank at the end of the period.