Nobuo Shirahashi, 63, was arrested for allegedly falsifying data in clinical studies that were then used to promote the blood-pressure drug Valsartan. Prosecutors raided the offices of Novartis Pharma KK in Tokyo after a university said the data may be skewed. The studies suggested the drug — sold under the name Diovan in Japan, and licensed for use in more than 100 countries — could help prevent strokes and angina. The firm used data from the studies to market its drug, playing up its supposed additional benefits. There is no suggestion that Diovan is ineffective in combating blood pressure problems. The pharmaceutical giant's Japan unit has also been embroiled in another scandal in which it was alleged possible side effects of leukaemia treatments had not been properly disclosed. In April, Novartis replaced top executives at its Japanese arm over the allegations. Under Japan's pharmaceutical law, anyone found guilty of exaggerating advertising can face up to two years in prison or a fine of up to two million yen ($19,000).