Atara Biotherapeutics : Quarterly Report for Quarter Ending March 31 2026 (Form 10-Q)

Published: 2026-05-12 16:39:41 ET ATRA

Published on 05/12/2026 at 04:39 pm EDT

Management's Discussion and Analysis of Financial Condition and Results of Operations

You should read the following discussion and analysis of our financial condition and results of operations together with our condensed consolidated financial statements and related notes included elsewhere in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2026 and our Annual Report on Form 10-K for the year ended December 31, 2025. This discussion and other parts of this Quarterly Report contain forward-looking statements that involve risk and uncertainties, such as statements of our plans, objectives, expectations and intentions. As a result of many factors, including those factors set forth in the "Risk Factors" section of this Quarterly Report, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

Atara Biotherapeutics is a leader in T-cell immunotherapy, leveraging its novel allogeneic Epstein-Barr virus (EBV) T-cell platform to develop transformative therapies for patients with cancer and autoimmune disease. Tab-cel (tabelecleucel) has received marketing authorization approval (MAA) under the proprietary name Ebvallo™ for commercial sale in the European Economic Area (EEA) by the European Commission (EC), for commercial sale and use in the United Kingdom (UK) by the Medicines and Healthcare products Regulatory Agency (MHRA), and for commercial sale and use in Switzerland by Swissmedic. We are partnered with Pierre Fabre Medicament (Pierre Fabre) for commercialization in Europe and potential commercialization, if approved, worldwide, including in the U.S. Tab-cel is currently in Phase 3 development in the U.S. for patients with EBV- associated post-transplant lymphoproliferative disease (EBV+ PTLD) who have failed rituximab or rituximab plus chemotherapy, as well as other EBV-driven diseases.

In March 2025, we announced our decision to pause development of our allogeneic CAR T cell programs and to discontinue development operations for our CAR T programs, including all clinical trials evaluating ATA3219 and development operations for ATA3431. We have completed nearly all wind-down activities for the CAR T programs. We have also stopped development on ATA188, an allogeneic T-cell immunotherapy targeting multiple sclerosis (MS).

Our T-cell immunotherapy platform is potentially applicable to a broad array of targets and diseases. Our off-the-shelf, allogeneic T-cell platform allows for rapid delivery of a T-cell immunotherapy product manufactured in advance of patient need and stored in inventory, with each manufactured lot of cells providing therapy for numerous potential patients. This differs from autologous treatments, in which each patient's own cells must be extracted, genetically modified outside the body and then delivered back to the patient, requiring a complex logistics network. We select the appropriate set of cells for use based on a patient's unique immune profile.

In October 2021, we entered into the Commercialization Agreement with Pierre Fabre (Pierre Fabre Commercialization Agreement), pursuant to which we granted to Pierre Fabre an exclusive, field-limited license to commercialize and distribute Ebvallo in Europe and select emerging markets in the Initial Territory following regulatory approval. As contemplated by the Pierre Fabre Commercialization Agreement, we entered into (i) a Manufacturing and Supply Agreement (ii) a Pharmacovigilance Agreement (iii) and a Quality Agreement, in each case, with Pierre Fabre to further advance our partnership with Pierre Fabre. In September 2022, we amended the Pierre Fabre Commercialization Agreement and received an additional $30 million milestone payment from Pierre Fabre following EC approval of Ebvallo for EBV+ PTLD and subsequent filing of the MAA transfer to Pierre Fabre, in exchange for, among other things, a reduction in: (i) royalties we are eligible to receive as a percentage of net sales of Ebvallo in the Initial Territory, and (ii) the supply price mark up on tab-cel purchased by Pierre Fabre. Additionally, we agreed to extend the time period for provision of certain services to Pierre Fabre under the Pierre Fabre Commercialization Agreement. In December 2022, we entered into the HCRx Agreement with HCR Molag Fund L.P. (HCRx,) a Delaware limited partnership. Pursuant to the terms of the HCRx Agreement, we received a total investment amount of $31 million in exchange for HCRx being entitled to receive a portion of the tiered, sales-based royalties for Ebvallo, in amounts ranging from the mid-single digits to significant double digits, as well as certain milestone payments, both related to the Initial Territory and otherwise payable to us by Pierre Fabre. The total royalties and milestones payable to HCRx related to the Initial Territory under the HCRx Agreement are capped between 185% and 250% of the total investment amount by HCRx, dependent upon the timing of such royalty and milestone payments to HCRx.

On October 31, 2023, we entered into an amended and restated Pierre Fabre Commercialization Agreement (A&R Commercialization Agreement), pursuant to which we expanded Pierre Fabre's exclusive rights to research, develop, manufacture, commercialize and distribute tab-cel (Ebvallo) to include all other countries in the world (Additional Territory) in addition to the Initial Territory (together, the Territory), subject to our performance of certain obligations as described below. In December 2023, upon the effective date of the A&R Commercialization Agreement, we met the contractual right to receive an additional upfront cash payment of $20.0 million for the expanded exclusive license grant, for which the cash was received in January 2024. In March 2024, we met the contractual right to receive $20.0 million in milestone payments upon achieving a regulatory milestone, for which the cash was received in April 2024. In July 2024, we met the contractual right to receive an

additional $20.0 million in milestone payments upon achieving acceptance of our biologics license application (BLA) for tab-cel by the United States Food and Drug Administration (FDA) and we received the cash in August 2024. In March 2025, we completed the transfer of all manufacturing responsibility to Pierre Fabre under the A&R Commercialization Agreement Amendment. Pierre Fabre is now responsible for manufacturing and supplying tabelecleucel for development and commercialization worldwide at its cost. Pursuant to the A&R Commercialization Agreement Amendment, Pierre Fabre has also agreed to assume the costs related to remediation of the third party manufacturing facility to address the FDA's requests to support resubmission of the BLA for tab-cel. In exchange for accelerating the transfer of all manufacturing responsibility and assumption of such remediation costs by Pierre Fabre, among other things, we agreed to reduce the amount of certain potential future regulatory and commercial milestone payments under the A&R Commercialization Agreement. In July 2025, we further amended the A&R Commercialization Agreement and completed the transfer of all clinical (including sponsorship of the ALLELE and tab-cel multi-cohort studies) and development responsibility to Pierre Fabre. Pierre Fabre is, at its cost, responsible for all clinical (including sponsorship of the ALLELE and tab-cel multi-cohort studies) and development activities (other than responsibility for regulatory activities) for tabelecleucel worldwide. In October 2025, we further amended the A&R Commercialization Agreement to transfer all regulatory activities (including sponsorship of the tab-cel BLA) to Pierre Fabre. Pierre Fabre is, at its cost, responsible for all regulatory activities (including sponsorship of the tab-cel BLA) for tab-cel worldwide, and Pierre Fabre is to use commercially reasonable efforts to obtain BLA approval as soon as possible. We will, at Pierre Fabre's expense, continue to observe the regulatory activities and support Pierre Fabre in its efforts to obtain BLA approval. In December 2025, we amended the A&R Commercialization Agreement to, among other things, mitigate the impact of the cost of rebuilding commercial inventory in the United States. We agreed to reduce the milestone payment due upon BLA approval of tab-cel to $31.0 million in exchange for the right to receive an additional $15.0 million potential milestone payment upon achieving a certain commercial milestone. Under the terms of the A&R Commercialization Agreement, as amended by the A&R Commercialization Agreement Amendment, we are entitled to receive an aggregate of up to $308.0 million in remaining milestone payments upon achieving certain regulatory and commercial milestones relating to tab-cel in the Initial Territory, and an aggregate of up to $556.0 million in additional potential milestone payments upon achieving certain regulatory and commercial milestones relating to tab-cel in the Additional Territory, including up to $31.0 million in potential regulatory milestones in connection with the approval by the FDA of a BLA for tab-cel. We are also eligible to receive significant double-digit tiered royalties as a percentage of net sales of tab-cel (Ebvallo) in the Territory until the later of 12 years after the first commercial sale in each such country, the expiration of specified patent rights in each such country, or the expiration of all regulatory exclusivity for tab-cel in each such country. Royalty payments may be reduced in certain specified customary circumstances. Royalties and milestones from the commercialization of Ebvallo in the Initial Territory remain subject to the HCRx Agreement.

We entered into research collaborations with leading academic institutions such as Memorial Sloan Kettering Cancer Center (MSK) and the Council of the Queensland Institute of Medical Research (QIMR Berghofer) pursuant to which we acquired rights to novel and proprietary technologies and programs. In May 2025, we returned the rights to the ATA188 and EBV Vaccine programs to QIMR Berghofer.

We and FUJIFILM Diosynth Biotechnologies California, Inc. (FDB) entered into a Master Services and Supply Agreement (Fujifilm MSA), which became effective in April 2022 and could extend for up to ten years. Pursuant to the Fujifilm MSA, FDB will supply us with specified quantities of our cell therapy products (if approved) and product candidates, manufactured in accordance with cGMP standards. The Fujifilm MSA does not obligate us to purchase products and product candidates exclusively from FDB. In March 2025, in connection with the transition of manufacturing responsibility for tab-cel to Pierre Fabre, we assigned and Pierre Fabre assumed, the Fujifilm MSA.

We had non-cancellable minimum commitments for products and services, subject to agreements with a term of greater than one year, with CROs and CMOs. In March 2025, the CMO agreements were assigned to Pierre Fabre as part of the A&R Commercialization Agreement Amendment, and we have been relieved of our obligations under the CMO agreements as of June 30, 2025. In July 2025, the CRO agreements were assigned to Pierre Fabre and we have been relieved of our obligations under the CRO agreements.

We have executed various strategic reductions in force over the past several years. As of March 31, 2026 and December 31, 2025, we had approximately $0.1 million and $0.9 million, respectively, of further separation payments and benefits required for these reductions in force. In the three months ended March 31, 2026 expenses related to reductions in force were $0. In the three months ended March 31, 2025 expenses related to reductions in force were approximately $9.8 million.

In January 2025, the U.S. Food and Drug Administration (FDA) issued a Complete Response Letter (Response Letter) for the Biologics License Application (BLA) for tab-cel as monotherapy treatment for adult and pediatric patients two years of age and older with Epstein-Barr virus positive post-transplant lymphoproliferative disease (EBV+ PTLD), who have received at least one prior therapy including an anti-CD20 containing regimen. The Response Letter only cited findings that arose during a pre-license inspection of a third party manufacturing facility for tab-cel. The Response Letter did not identify any

deficiencies related to the manufacturing process, the clinical efficacy, or clinical safety data in the BLA, and the FDA did not request any new clinical trials to support a potential approval of tab-cel. Additionally, in January 2025, the FDA placed a clinical hold on Atara's active Investigational New Drug (IND) applications. These INDs include the tab-cel program as monotherapy treatment for adult and pediatric patients two years of age and older with Epstein-Barr virus positive post-transplant lymphoproliferative disease (EBV+ PTLD). The clinical hold is directly linked to inadequately addressed Good Manufacturing Practices (GMP) compliance issues referenced in the Response Letter. In May 2025, the FDA notified us that we have satisfactorily addressed all clinical hold issues and the FDA has lifted the clinical holds. In May 2025, we aligned with the FDA on a plan to address the issues raised by the FDA in the Response Letter and the path forward for resubmission of the tab-cel BLA at a Type A meeting. In July 2025, we resubmitted, and the FDA accepted, the tab-cel BLA. In January 2026, the FDA issued a second Complete Response Letter (Second Complete Response Letter) for the BLA for tab-cel as monotherapy treatment for adult and pediatric patients two years of age and older with EBV+ PTLD, who have received at least one prior therapy including an anti-CD20 containing regimen. In the Second Complete Response Letter, the FDA confirmed that the GMP compliance issues identified in the Response Letter had been satisfactorily resolved, and importantly, no safety issues were raised. However, the Second Complete Response Letter claims that the ALLELE trial, previously confirmed by the FDA as adequate to support the BLA filing, is no longer considered to be an adequate and well-controlled study due to deficiencies in study design, conduct and analysis, to provide substantial evidence of effectiveness of tab-cel to treat relapsed or refractory EBV+ PTLD. In March 2026, our partner, Pierre Fabre, submitted a request for, and the FDA has granted, a Type A meeting to address the FDA's concerns in the Second Complete Response Letter. In April 2026, Pierre Fabre, with our support, had a productive meeting with the FDA and discussed with the FDA a potential path forward to resubmitting the tab-cel BLA. The FDA agreed that a single arm study using an appropriate historical control applicable to the trial population, conducted in a pre-specified manner, could serve as an adequate and well controlled study and provide safety and efficacy data in support of a future marketing application of tab-cel for the proposed indication. We plan to continue supporting Pierre Fabre as Pierre Fabre works with the FDA to reach alignment on a resubmission plan for the tab-cel BLA. We anticipate providing a regulatory update in the third quarter of 2026.

Review of Strategic Alternatives

Our board of directors regularly reviews our strategic plan, priorities, and opportunities as part of its commitment to act in the best interest of the Company and its stockholders. In January 2025, we announced that we had previously engaged a well-known financial advisor to support the assessment of opportunities to advance and realize value from our CAR T assets, for which we announced in March 2025 that we paused development. The advisor's scope was expanded to include a wider range of additional strategic alternatives designed to maximize value for our stockholders, which may include, but are not limited to, an acquisition, merger, reverse merger, other business combinations, sale of assets, licensing, or other strategic transactions. Through this process, we were in active discussions with several potential parties. However, there can be no assurance regarding the results or outcome of this process. It is possible that we may not pursue a strategic alternative or transaction or that any strategic alternative or transaction, if pursued, will not be completed on attractive terms, or that a strategic alternative or transaction may not ultimately be consummated. Our board of directors continues to evaluate potential strategic transactions.

Pipeline

Our most advanced T-cell immunotherapy program, tab-cel, is approved for commercial sale and use in the EEA, the UK and Switzerland under the proprietary name Ebvallo. We continue to advance development of tab-cel in the U.S. in a Phase 3 clinical trial for patients with EBV+ PTLD (ALLELE). Tab-cel has received Breakthrough Therapy Designation (BTD) in the U.S. for the treatment of patients with EBV+ PTLD after hematopoietic cell transplants (HCT) who have failed rituximab and orphan drug designation in the U.S. and UK for the treatment of patients with EBV+ PTLD following HCT or solid organ transplants (SOT).

Other Programs

ATA3431 is an allogeneic, bispecific CAR directed against CD19 and CD20 for B-cell malignancies and autoimmune disease, leveraging our 1XX CAR co-stimulatory domain and EBV T-cell platform and does not require TCR or HLA gene editing. Preclinical data presented at the American Society of Hematology 2023 demonstrated potential for potent antitumor activity, long-term persistence, and superior tumor growth inhibition compared to an autologous CD19/CD20 CAR T benchmark. In March 2025, we announced our decision to pause the development of our allogeneic CAR T cell programs and discontinue all development operations, including ATA3431. We completed nearly all wind-down activities for the CAR T cell programs. We continue to maintain the patent portfolio and related rights for the ATA3431 program as we evaluate options for this program.

We have also discontinued some programs and will return the programs to our collaborators. For example, in May 2025 we returned the rights to ATA188 and the EBV vaccine to QIMR Berghofer.

Manufacturing

In April 2022, we entered into the Fujifilm MSA, which could extend for up to ten years. Pursuant to the Fujifilm MSA, FDB will supply us with specified quantities of our product and product candidates, manufactured in accordance with cGMP standards. The Fujifilm MSA does not obligate us to purchase our product and product candidates exclusively from FDB. In March 2025, in connection with the transition of manufacturing responsibility for tab-cel to Pierre Fabre, we have assigned and Pierre Fabre has assumed, the Fujifilm MSA.

We worked with Charles River Laboratories (CRL) pursuant to a Commercial Manufacturing Services Agreement (CRL MSA) that we entered into in December 2019. The CRL MSA expired on August 31, 2024 and we have transitioned manufacturing responsibility for tab-cel to Pierre Fabre.

Financial Overview

We have a limited operating history. Since our inception in 2012, we have devoted substantially all of our resources to identify, acquire and develop our product candidates, including conducting preclinical and clinical studies, acquiring or manufacturing materials for clinical studies, and providing general and administrative support for these operations.

Our net income (loss) was ($4.1) million and $38.0 million for the three months ended March 31, 2026 and 2025, respectively. As of March 31, 2026, we had an accumulated deficit of $2.0 billion. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative expenses associated with our operations. As of March 31, 2026, our cash, cash equivalents and short-term investments totaled $8.4 million, which we intend to use to fund our operations.

Revenues

We have generated commercialization revenues under the A&R Commercialization Agreement, following the December 2022 EC approval of Ebvallo. Our commercialization revenue recognized to date is derived from agreements with Pierre Fabre, primarily related to upfront license fees, milestone payments and amounts recognized from the sale of zero-cost inventories for which all performance obligations are complete, and is subject to the terms of the HCRx Agreement. We do not retain any meaningful milestone or royalty payments related to the Initial Territory under the A&R Commercialization Agreement until the applicable royalty cap under the HCRx Agreement is met, if at all, and milestone or royalty payments related to the Additional Territory under the A&R Commercialization Agreement are subject to us obtaining regulatory approval in the US or for another market within the Additional Territory.

We expect that any revenue we generate from the A&R Commercialization Agreement, subject to the terms of the HCRx Agreement, will fluctuate from period to period as a result of the timing of potential milestone achievement and any potential regulatory approvals.

Cost of Commercialization Revenue

Cost of commercialization revenue consists primarily of expenses associated with cell selection services performed for Pierre Fabre, in-license sales-related milestone costs, period manufacturing expenses and the lower of cost or net realizable value adjustments to inventories. Costs incurred to produce Ebvallo prior to regulatory approval, referred to as zero cost inventories, have been recorded as research and development expense in our condensed consolidated statement of operations and comprehensive income (loss). Cost of commercialization revenue for Ebvallo produced after receiving regulatory approval and in a qualified manufacturing facility also include direct and indirect costs related to the production of Ebvallo. Such costs are recorded into cost of commercialization revenue as the related commercialization revenue is recognized. Such costs include, but are not limited to, CMO costs, quality testing and validation, materials used in production, and an allocation of compensation, benefits and overhead costs associated with employees involved with production.

Research and Development Expenses

The largest component of our total operating expenses since inception has been our investment in research and development activities, including the preclinical and clinical development of our product candidates. Research and development expenses consist primarily of compensation and benefits for research and development and regulatory support employees, including stock-based compensation; expenses incurred under agreements with contract research organizations and investigative sites that conduct preclinical and clinical studies; the costs of acquiring and manufacturing clinical study materials and other supplies, including expenses incurred under agreements with CMOs; payments under licensing and research and development agreements; other outside services and consulting costs; and facilities, information technology and overhead expenses. Research and development costs are expensed as incurred.

Our expenditures on future preclinical and clinical development programs are subject to numerous uncertainties in timing and cost to completion. The duration, costs, and timing of clinical studies and development of our product candidates will depend on a variety of factors, including:

The process of conducting the necessary clinical research to obtain approval from the FDA and other regulators is costly and time consuming and the successful development of our product candidates is highly uncertain. The risks and uncertainties associated with our research and development projects are discussed more fully in the section of this report titled "1A. Risk Factors." As a result of these risks and uncertainties, we are unable to determine with any degree of certainty the duration and completion costs of our research and development projects, or if, when, or to what extent we will generate revenues from the commercialization and sale of any of our product candidates that obtain regulatory approval.

General and Administrative Expenses

General and administrative expenses consist primarily of compensation and benefits for legal, human resources, finance and other general and administrative employees, including stock-based compensation; professional services costs, including legal, patent, human resources, audit and accounting services; other outside services; and consulting costs; and information technology and overhead expenses.

Interest Income

Interest income consists of interest earned on our cash, cash equivalents and short-term investments.

Interest Expense

Interest expense consists primarily of interest expense recorded in connection with the HCRx Agreement.

Critical Accounting Policies and Significant Judgments and Estimates

There have been no significant changes to our critical accounting policies and significant judgments and estimates during the three months ended March 31, 2026 from those disclosed in our management's discussion and analysis of financial condition and results of operations included in our Annual Report on Form 10-K for the year ended December 31, 2025 filed with the SEC on March 16, 2026.

Results of Operations

Comparison of the Three Months Ended March 31, 2026 and 2025

Revenues

Revenue consisted of the following in the periods presented:

Three Months Ended March 31,

Increase

2026

2025

(Decrease)

(in thousands)

Commercialization revenue

$

516

$

98,149

$

(97,633

)

Commercialization revenues were $0.5 million for the three months ended March 31, 2026 as compared to $98.1 million in the comparative 2025 period. The revenue in the prior-year period reflects the transfer of tab-cel manufacturing responsibilities to Pierre Fabre on March 31, 2025, which resulted in a one-time acceleration of revenue recognized upon satisfaction of substantially all commercialization and transition-related performance obligations. In the current period, commercialization revenues relate solely to ongoing regulatory activities, resulting in significantly lower revenue recognized during the three months ended March 31, 2026.

Cost of commercialization revenue

Cost of commercialization revenue consisted of the following in the periods presented:

Three Months Ended March 31,

Increase

2026

2025

(Decrease)

(in thousands)

Cost of commercialization revenue

$

124

$

20,439

$

(20,315

)

Cost of commercialization revenue was $0.1 million for the three months ended March 31, 2026, as compared to $20.4 million in the comparative 2025 period. The decrease in the 2026 period is primarily due to the recognition of deferred cost of commercialization revenue in the prior-year period upon the transfer of manufacturing responsibilities to Pierre Fabre on March 31, 2025.

Research and development expenses

Research and development expenses consisted of the following costs, by function, in the periods presented:

Three Months Ended March 31,

Increase

2026

2025

(Decrease)

(in thousands)

Technical operations and quality expenses

$

1,036

$

19,273

$

(18,237

)

Medical and safety expenses

(1,348

)

5,334

$

(6,682

)

Regulatory expenses

476

2,826

(2,350

)

Total research and development expenses

$

164

$

27,433

$

(27,269

)

Technical operations and quality expenses were $1.0 million in the three months ended March 31, 2026, as compared to $19.3 million in the comparative 2025 period. The decrease in 2026 was primarily due to the transition of tab-cel manufacturing activities to Pierre Fabre as of March 31, 2025 and reduced headcount following the 2025 reductions in force.

In the three months ended March 31, 2026 medical and safety expenses were approximately ($1.3) million, which reflects a change in estimate of final clinical related costs upon agreement being reached in this period. In the three months ended March 31, 2025 medical and safety expenses totaled $5.3 million. The decrease in 2026 was primarily due to reduced headcount following the 2025 reductions in force, transition of tab-cel clinical trials to Pierre Fabre in July 2025, and termination of the ATA3219 phase 1 trials after decision to pause research and development for CAR T assets in March 2025.

Regulatory expenses were $0.5 million in the three months ended March 31, 2026, as compared to $2.8 million in the comparative 2025 period. The decrease in 2026 was primarily due to reduced headcount following the 2025 reductions in force.

General and administrative expenses

Three Months Ended March 31,

Increase

2026

2025

(Decrease)

(in thousands)

General and administrative expenses

$

3,597

$

11,475

$

(7,878

)

General and administrative expenses were $3.6 million in the three months ended March 31, 2026, as compared to $11.5 million in the respective comparative 2025 period. The decrease in 2026 was primarily due to reduced headcount following the 2025 reductions in force and lower general and administrative expenses.

Other income (expense), net

Three Months Ended March 31,

Increase

2026

2025

(Decrease)

(in thousands)

Interest income

$

54

$

236

$

(182

)

Interest expense

(830

)

(1,017

)

187

Other income (expense), net

-

(11

)

11

Total other income (expense), net

$

(776

)

$

(792

)

$

16

Interest income was $54,000 in the three months ended March 31, 2026, as compared to $0.2 million in the comparative 2025 period. The decrease in the 2026 period was primarily due to lower average balances of cash, cash equivalents and available-for-sale securities.

Interest expense was $0.8 million in three months ended March 31, 2026, as compared to $1.0 million in the comparative 2025 period, primarily due to lower finance lease interest expense.

Liquidity and Capital Resources

Sources of Liquidity

Since our inception in 2012, we have funded our operations primarily through the issuance of common and preferred stock, issuance of pre-funded warrants to purchase common stock, upfront fees and milestone payments from the Research, Development and License Agreement with Bayer and the A&R Commercialization Agreement and the sale of the ATOM Facility to FDB in 2022.

In the past five years, we have entered into two separate sales agreements with Cowen and Company, LLC (Cowen): in November 2021 (2021 ATM Facility) and in November 2023 (2023 ATM Facility). Each ATM facility provides or provided for the sale, in our sole discretion, of shares of our common stock having an aggregate offering price of up to $100.0 million, through Cowen, as our sales agent. We filed a registration statement on Form S-3 registering the offer and sale of these shares under the Securities Act (2023 Registration Statement). Upon the effectiveness of the 2023 Registration Statement, the 2021 ATM Facility was terminated, and no further sales can be made under the 2021 ATM Facility. The issuance and sale of these shares by us pursuant to the ATM facilities are deemed "at the market" offerings defined in Rule 415 under the Securities Act

of 1933, as amended (Securities Act), and were registered under the Securities Act. Commissions of up to 3.0% are due on the gross sales proceeds of the common stock sold under each ATM facility.

In May 2025, we issued and sold 834,237 shares of common stock at an offering price of $6.61 per share and pre-funded warrants to purchase 1,587,108 shares of common stock at an offering price of $6.6099 per warrant in an underwritten registered direct offering pursuant to a shelf registration on Form S-3. The gross proceeds from this sale were $16.0 million, resulting in net proceeds of $14.8 million after deducting underwriting discounts and commissions and offering expenses payable by us.

During the three months ended March 31, 2026, we sold an aggregate of 493,117 shares of common stock under the 2023 ATM Facility, at an average price of $6.08 per share, for gross proceeds of $3.0 million and net proceeds of $2.9 million, after deducting commissions and other offering expenses payable by us.

As of March 31, 2026, we had $84.2 million of common stock remaining and available to be sold under the 2023 ATM Facility. Subsequent to March 31, 2026, we sold an aggregate of 497,900 shares of our common stock under the 2023 ATM Facility at an average price of $9.84 per share, for net proceeds of $4.8 million, after deducting commission expenses payable by us.

In March 2025, we completed the transfer of all manufacturing responsibility to Pierre Fabre and Pierre Fabre is, at its cost, responsible for manufacturing and supplying tabelecleucel for development and commercialization worldwide under an amendment to the A&R Commercialization Agreement (A&R Commercialization Agreement Amendment). Pursuant to the A&R Commercialization Agreement Amendment, Pierre Fabre has also agreed to assume the costs related to remediation of the third party manufacturing facility to address the FDA's requests to support resubmission of the BLA for tab-cel. In exchange for accelerating the transfer of all manufacturing responsibility and assumption of such remediation costs by Pierre Fabre, among other things, we agreed to reduce the amount of certain potential future regulatory and commercial milestone payments under the A&R Commercialization Agreement.

We have incurred losses and negative cash flows from operations in each year since inception and have generated limited commercialization revenues from the A&R Commercialization Agreement, following the December 2022 EU regulatory approval of Ebvallo, which is subject to the terms of the HCRx Agreement. We do not maintain any meaningful milestone or royalty payments from Pierre Fabre relative to the Initial Territory until the applicable royalty cap under the HCRx Agreement is met, if at all. We continue to incur significant research and development and other expenses related to our ongoing operations and expect to incur losses for the foreseeable future. As a result, we will need additional capital to fund our operations, which we may raise through a combination of equity offerings, debt financings, other third party funding and other collaborations, strategic alliances and partnering arrangements. We may borrow funds on terms that may include restrictive covenants, including covenants that restrict the operation of our business, liens on assets, high effective interest rates and repayment provisions that reduce cash resources and limit future access to capital markets. In addition, we expect to continue to opportunistically seek access to additional funds through additional public or private equity offerings or debt financings including by utilizing the 2023 ATM Facility, through potential collaboration, partnering or other strategic arrangements, or a combination of the foregoing. To the extent that we raise additional capital by issuing equity securities, our stockholders may experience substantial dilution. To the extent that we raise additional funds through collaboration or partnering arrangements, we may be required to relinquish some of our rights to our technologies or rights to market and sell our products in certain geographies or grant licenses or other rights on terms that are not favorable to us.

As of the date of the filing of our Annual Report on Form 10-K for the year ended December 31, 2025, our public float was less than $75 million. As a result, we are subject to the limitations of General Instruction I.B.6 to Form S-3 until such time as our public float exceeds $75 million, which means we only have the capacity to sell shares up to one-third of our public float under shelf registration statements in any twelve-month period. We will remain constrained by the limitations of General Instruction I.B.6 to Form S-3 until such time as our public float exceeds $75 million, at which time the number of securities we may sell under a Form S-3 registration statement will no longer be limited by limitations of General Instruction I.B.6 to FormS-3. Consistent with a recent SEC Corporation Finance Interpretation, the limitations of General Instruction I.B.6 of Form S-3 do not apply to the 2023 ATM Facility.

Cash in excess of immediate requirements is invested in accordance with our investment policy, primarily with a view to liquidity and capital preservation. Currently, our cash, cash equivalents and short-term investments are held in bank and custodial accounts and consist of money market funds, U.S. Treasury, and corporate debt obligations.

Our cash and cash equivalents totaled $8.4 million and $8.5 million as of March 31, 2026 and December 31, 2025, respectively.

Cash Flows

Comparison of the Three Months Ended March 31, 2026 and 2025

The following table details the primary sources and uses of cash for each of the periods set forth below:

Three Months Ended March 31,

2026

2025

(in thousands)

Net cash (used in) provided by:

Operating activities

$

(3,073

)

$

(28,138

)

Investing activities

-

17,199

Financing activities

2,951

(250

)

Net increase (decrease) in cash, cash equivalents and restricted cash

$

(122

)

$

(11,189

)

Operating activities

Net cash used in operating activities was $3.1 million in the three months ended March 31, 2026 as compared to $28.1 million in the comparative 2025 period. The decrease of $25.0 million was primarily due to lower compensation-related costs resulting from lower headcount driven by the 2025 reductions in force, as well as transition of tab-cel clinical trials and manufacturing activities to Pierre Fabre in 2025.

Investing activities

Net cash provided by investing activities in the three months ended March 31, 2026 was $0 as compared to $17.2 million in the comparative 2025 period, primarily reflecting proceeds from maturities and sales of available-for-sale securities.

Financing activities

Net cash provided by financing activities in the three months ended March 31, 2026 consisted of $3.0 million of net proceeds received from the 2023 ATM Facility. Net cash used in financing activities in the comparative 2025 period primarily consisted of $0.3 million in principal payments on finance lease obligations.

Operating Capital Requirements and Plan of Operations

We do not know when, or if, we will generate sufficient revenue from commercialization to offset our operating expenses. We anticipate that we will continue to generate losses for the foreseeable future, and we expect the accumulated losses to increase as we continue the development of, and seek regulatory approvals for, our product candidate. We are subject to all of the risks inherent in the development of new products, and we may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. We anticipate that we will need to raise substantial additional funding in the near term to finance our planned operations.

Our operating plan may change as a result of many factors currently unknown to us, and we may need additional funds sooner than planned. We do not have any committed external source of funds other than milestone and royalty payments that we may receive under the A&R Commercialization Agreement, subject to the terms of the HCRx Agreement. We do not retain any meaningful milestone or royalty payments related to the Initial Territory from Pierre Fabre until the applicable royalty cap under the HCRx Agreement is met, if at all.

Our existing cash, cash equivalents and short-term investments as of March 31, 2026 will not be sufficient to fund our planned operations for at least the next 12 months after the date of issuance of these financial statements. These conditions raise substantial doubt about our ability to continue as a going concern for at least 12 months after the issuance of the accompanying condensed consolidated financial statements.

In order to complete the process of obtaining regulatory approval for tab-cel in the US, we may require substantial additional funding. We expect to continue to seek access to additional funds through additional public or private equity offerings or debt financings, through potential collaboration, partnering or other strategic arrangements, or a combination of the foregoing. If we are unable to obtain sufficient funding on acceptable terms, we could be forced to further delay, limit, reduce or terminate clinical studies or other development activities.

We have based our projections of operating capital requirements on assumptions that may prove to be incorrect, and we may use all of our available capital resources sooner than we expect. Because of the numerous risks and uncertainties associated with research, development and commercialization of pharmaceutical products, we are unable to estimate the exact amount of our operating capital requirements. Our future funding requirements will depend on many factors, including, but not limited to:

Until we are able to generate a sufficient amount of net cash inflows from operations, which we may never do, meeting our long-term capital requirements is in large part reliant on access to public and private equity and debt capital markets, augmented by cash generated from operations and interest income earned on the investment of our cash balances. We expect to continue to seek access to the equity and debt capital markets to support our development efforts and operations. To the extent that we raise additional capital by issuing equity securities, our stockholders may experience substantial dilution. To the extent that we raise additional funds through commercialization, collaboration or partnering arrangements, we may be required to relinquish some of our rights to our technologies or rights to market and sell our products in certain geographies, grant licenses or other rights on terms that are not favorable to us, or issue equity that may be substantially dilutive to our stockholders.

As a result of economic conditions, general global economic uncertainty, political change and other factors, we do not know whether additional capital will be available when needed, or that, if available, we will be able to obtain additional capital on reasonable terms. If we are unable to raise additional capital due to the volatile global financial markets, general economic uncertainty or other factors, we will be forced to delay, limit, reduce or terminate preclinical studies, clinical studies or other development activities for one or more of our product candidates.

Contractual Obligations and Commitments

Our contractual obligations primarily consist of our obligations under non-cancellable operating and finance leases and contracts we enter into in the normal course of business with CROs for clinical studies, with CMOs for clinical and commercial materials, and with other vendors for preclinical studies and supplies and other services and products for operating purposes. These contracts generally provide for termination for convenience following a notice period. There have been no material changes to our contractual obligations and commitments reported in our Annual Report on Form 10-K for the year ended December 31, 2025 filed with the SEC on March 16, 2026 other than those previously discussed in this document.

Disclaimer

Atara Biotherapeutics Inc. published this content on May 12, 2026, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on May 12, 2026 at 20:35 UTC.