Tokyo prosecutors said on Tuesday they will charge the Japanese unit of Novartis AG and a former employee in connection with allegations of data manipulation in promoting its best-selling blood pressure drug Diovan.

The prosecutors office said in a statement that it had decided to arrest Nobuo Shiraishi on allegations he gave false data to researchers whose work was used for advertising. Shiraishi was initially detained in June.

The prosecutor also said that Novartis Pharma KK, the Swiss drugmaker's wholly owned local subsidiary, will be charged in connection with the case under a provision that alleges responsibility for failing to oversee an employee.

Novartis said it was cooperating with an ongoing investigation by the Japanese authorities and had taken corrective measures, including replacing senior management of its Japan subsidiary.

"Novartis and NPKK have already undertaken decisive action to address problems with the company's Investigator-Initiated Trial (IIT) research programmes in Japan," David Epstein, the company's global division head, said in a statement.

"We are committed to changing the culture at Novartis Pharma KK and demonstrating ethical leadership among pharmaceutical companies in Japan," he added.

Any individual found guilty of exaggerated advertising of drugs in Japan can be punished with up to two years in prison or a fine of as much as 2 million yen ($19,700) or both.