(Updates stock price.)Hisamitsu Pharmaceutical announced Tuesday a move to build up its presence in the U.S. The Japanese-based company entered an agreement in which it will buy Noven Pharmaceuticals ( NOVN) in an all-cash tender for $428 million, or $16.50 a share. The price represents a 22% premium to Noven's closing price Monday of $13.48. Noven shares retained that value during Tuesday trading, holding steady at $16.46 by mid-day. "The proposed acquisition by Hisamitsu -- a company Noven has come to know, respect and trust over the course of several years -- provides substantial value to Noven shareholders, while positioning Noven as the U.S. growth platform of a global company with significant resources and a vision aligned with our own," said Noven CEO Peter Brandt in a press release. The deal was approved by the boards of both companies and a 20-day tender process is set to begin by July 28. Hisamitsu already owns 1.24 million Noven shares, or 4.9% of the outstanding shares. In a separate press release Tuesday, Noven announced positive phase II clinical trial results for Mesafem, a treatment for hot flashes associated with menopause.