Jürgen Drews, Fritz Bühler and Stephan Ryser all have joined Bear Stearns Asset Management in the past six months. But that doesn't mean there's no one minding the store at the CHF290 million ($160 million) venture fund co-founded by the three Roche alumni as International Biomedicine Management Partners.

According to Elizabeth Kessler, CEO of the firm's holding company, International BM Biomedicine Holdings, Drews' group was focused on trolling for new investments and was not responsible for management of the fund. The holding company manages the day-to-day operations and makes the final decisions on all proposed investments, she said.