Novartis AG shareholder Artisan Partners said the Swiss drugmaker needs to shake up its board and improve dealmaking after its shares plunged following three major clinical trial setbacks, Reuters reported.

"The party is over" at Novartis and Chairman Giovanni Caforio, who assumed his role last year, needs to take action, Artisan managing director David Samra told Reuters in an interview.

Artisan Partners, a major investor in Novartis, criticized the company's response to recent clinical trial failures and called for urgent changes in leadership and M&A strategy to restore investor confidence.