Shares of Dr Reddy's Laboratories fell as much as 3.9 per cent, their lowest since January 22, 2016.

The stock fell as the company said it has received an unfavourable ruling in a US court regarding a patent infringement case over antinausea injection Aloxi.

In a BSE filing, Reddy’s Laboratories said: “The United States District Court for the District of New Jersey issued its opinion regarding Helsinn Healthcare’s patent infringement claims against Dr Reddy’s proposed palonosetron product.“

“The court found that Dr Reddy’s proposed palonosetron hydrochloride 0.25 mg/5 ml infringes on certain claims of US patents...and that the asserted claims were not valid.“

Helsinn Healthcare SA is a Switzerland-based pharma company.

“We are disappointed in the decision and intend to pursue an appeal in due course,” a company spokesperson said.

Aloxi injection is used in adults to help prevent the nausea and vomiting due to chemotherapy.

Dr Reddy's stock was among the top losers on the broader NSE index.

The stock posts biggest intraday percentage loss since November 9, 2016.

About 480,000 shares traded, nearly double the stock's 30-day average volume.

As of Wednesday's close, the stock was down 4.9 per cent this year.