Atara Biotherapeutics Inc. plans to optimize the value of its six programs by allocating them across three companies that Atara will manage. Its initial series B close of $38.5 million will fund development of the two most advanced programs.

Amgen Inc. and Kleiner Perkins Caufield & Byers launched Atara in 2012 to develop six of Amgen's "deprioritized programs" that target proteins in the transforming growth factor (TGF) beta (TGFB) family. The company raised $20 million in series A funding this year from Kleiner Perkins (KPCB), DAG Ventures, Alexandria Venture Investments, Domain Associates and private investors.