After pricing one of Japan's richest-ever biotech IPOs, Acucela Inc. (Tokyo:4589) managed to avoid the downdraft affecting Japanese life science stocks as the ophthalmic play finished its first week up 20%.

The Seattle company raised ¥16.6 billion ($162.4 million) through the sale of 9.2 million shares at ¥1,800 ($17.65) on Feb. 3 on Tokyo Stock Exchange's Mothers, besting the recent high-water mark of ¥12.7 billion ($121 million) raised by genitourinary, inflammation