Atara Biotherapeutics, Inc. Q3 FY2022 earnings call

• Ebvallo (tab-cel) received CHMP positive opinion for first indication, on track for EU approval by end 2022; Pierre Fabre preparing for EU launch in Q1 2023. • Progress with tab-cel in US: Type A CMC meeting with FDA completed, Type B clinical meeting granted, expect Q1 2023 guidance on BLA submission. • Presented updated ALLELE study data at ASH 2022, including EBV-positive PTLD and leiomyosarcoma data. • ATA188 Phase 1 study data on progressive MS, including MRI biomarker and OLE results; Phase 2 EMBOLD study readout expected in Oct 2023. • ATA2271 Phase 1 study resumed enrollment after pause; ATA3219 manufacturing optimization progressing, IND filing expected Q2 2023.

No detailed breakdown of financial performance by product segments in terms of absolute revenue and contribution % provided in the transcript.

• No revenue guidance for EU tab-cel at present; plan to provide more on pricing post-EU launch in 2023. • Expect Q1 2023 guidance on tab-cel BLA submission progress. • ATA188 Phase 2 EMBOLD study primary endpoint readout expected in Oct 2023. • ATA3219 IND filing expected in Q2 2023.

• Actual results could differ materially from forward-looking statements due to risks and uncertainties associated with the business, as qualified by cautionary statements in press release and SEC filings.

Q: Curious if plan to provide EU tab-cel revenues guidance in 2023 and logistical hurdles for first allo T-cell product in Europe, and gating factors for US commercial partnership.

A: Not planning revenue guidance for Europe at present; logistical aspects related to biologic launch are manageable with Pierre Fabre; on US partnership, involves finding right partner, negotiating value split, and aligning with FDA BLA submission timing.

Q: Comment on number of patients treated with tab-cel commercial formulation and follow-up time.

A: Had constructive dialogues with FDA about using commercially treated tab-cel patients for BLA submission, not commenting on specific patient numbers and follow-up yet but things are poised well.

Q: Size and scope of ATA2271 data at ESMO, details on fatal SAE and study resumption.

A: Will present safety data, PK data, and translational work on the fatal SAE; study resumed after FDA agreement on protocol amendment including washout criteria and return to cohort two dose.

Q: Guidance on FDA meetings for tab-cel, clinical parts gating, and strategic rationale for US partnership.

A: Type B meeting to align on clinical data package for pre-BLA; clinical parts gating depends on FDA meeting; strategic rationale for US partnership is to avoid commercialization investment, get cash inflows, and extend cash runway.

Q: Color on tab-cel clinical data package requirements, cash runway extension with US partner, and ATA188 partnership updates.

A: Clinical data package leverages commercially treated patients and robust clinical experience; not commenting on cash runway extension specifics; ATA188 partnering involves discussing with companies, considering value inflection point from EMBOLD readout.

Q: Confidence in one year being sufficient for ATA188 Phase 2 data.

A: Confidence driven by Phase 1 data where almost all confirmed disability improvers improved within first 12-month time frame.