With the Delhi High Court's verdict, Daiichi Sankyo has scored a victory against former Ranbaxy promoters. But it won't end there.

The stock fell after the drug major received a warning letter from US FDA on their API manufacturing facilities at Srikakulam and Oncology formulation facility at Duvvada in Andhra Pradesh.

The company has withdrawn its appeal in the lawsuit filed by erstwhile Ranbaxy Laboratories Ltd in November 2014 in a US District Court against US Food and Drug Administration, Sun Pharma said in a regulatory filing on Friday.

The drug company has launched the generic version of Astrazeneca's Nexium, which is used to treat acid reflux in the US market.

Sun Pharma Advanced Research Co Ltd (SPARC) closed 2.62 per cent down at Rs 375.80 apiece on Monday after USFDA revoked approval for SPARC's seizure drug, citing manufacturing quality problems at its production site.

Industry observers feel it would take a lot of effort for Wockhardt to regain its glory and it won't be easy considering the company's business mix, strategies and product portfolio.

Trading in Ranbaxy shares will be suspended from April 6 due to amalgamation with Sun Pharmaceutical Industries.

Ranbaxy said it was disappointed with the result and was pursuing all available legal options to preserve its rights.

The government sought to put controls on drugmakers when it came to pricing of essential drugs, including those for common cough and cold as also for cancer and other diseases.

Sun Pharmaceutical's move to acquire Ranbaxy is arguably the high point of 2014 for the pharmaceutical sector.

The lawsuit challenged a 2008 settlement in a patent suit between the two pharma cos. Plaintiffs claim the settlement gave Ranbaxy nearly $1 bn to delay launch of Nexium.

The latest EU ban on the Dewas plant was enforced after German regulators also found quality lapses during an inspection of the site.

After an inspection in June, Germany's drug regulator issued a 'non-compliance' report for the Madhya Pradesh plant where Ranbaxy made the antibiotic Cephalosporin.

The Sun Pharma Advanced Research Company stock closed 9.7 per cent higher on the BSE.

Ranbaxy Laboratories had sued US Food and Drug Administration (USFDA) over revoking an approval to sell generic versions of Nexium and Valcyte in the US market.

Ranbaxy had sought a restraining order against Dr Reddy's Laboratories and US-based firm Endo International from launching copies of Nexium and Valcyte drugs in the US.

Also, the drug maker is being moved out of the National Stock Exchange's CNX Nifty Junior index, which stoked selling pressure, brokers said.

The FDA told Ranbaxy that its decision to grant approvals for both the drugs were \"in error\", after it found that Ranbaxy's plants did not meet its quality standards.

The FDA has also denied Ranbaxy 180-day marketing exclusivity for a generic version of Roche's antiviral drug Valcyte, according to a company statement on Thursday.