Form 3 Filing by EcoR1 Capital, LLC and related parties for Atara Biotherapeutics, Inc.

This filing is a Form 3, which reports initial beneficial ownership of securities. EcoR1 Capital, LLC, along with its affiliated fund Qualified Fund and its manager Oleg Nodelman, are the reporting persons. They jointly report beneficial ownership of 1,044,593 shares of Atara Biotherapeutics, Inc. Common Stock. Qualified Fund directly beneficially owns 970,829 shares, and EcoR1 Capital, LLC may be deemed to indirectly beneficially own the shares as the investment adviser to the fund. Oleg Nodelman may be deemed to indirectly beneficially own the shares as the control person of EcoR1. The reporting persons disclaim beneficial ownership except to the extent of their respective pecuniary interests.