EXHIBIT 10.6

Exhibit 10.6

SPECIFIC TERMS IN THIS EXHIBIT HAVE BEEN REDACTED BECAUSE SUCH TERMS ARE BOTH NOT MATERIAL AND ARE THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE OR CONFIDENTIAL. THESE REDACTED TERMS HAVE BEEN MARKED IN THIS EXHIBIT WITH THREE ASTERISKS AS [***].

June 19, 2026

Vaxart Biosciences Inc 170

Harbor Way Ste 300

South San Francisco, California 94080

Dear [***]:

In accordance with the terms and conditions of the referenced RRPV Base Agreement, Modification No. 07 hereby amends the Project Award No. 01 as follows:

DESCRIPTION OF MODIFICATION

The total estimated ceiling for this Project Award is $[***] broken out as follows:

Firm Fixed Price

The total fixed amount for the services to be provided by the Project Awardee are as follows:

Estimated Expenditure and Fixed Fee

The total estimated expenditure and fixed fee for the services to be provided by the Project Awardee are as follows:

The total amount of funding currently allotted to this Project Award and available for payment is $344,795,504. Additional funds up to the Reserve ceiling of $[***] can be requested and may be approved provided Vaxart has an acceptable technical justification. However, Vaxart acknowledges that any costs above the agreed upon contract ceiling amount of $[***] will be the sole responsibility of Vaxart.

2)    The Incremental Funding clause of the Project Award is modified to read as indicated in bold below:

5. Incremental Funding

The total amount of funding currently allotted to this Project Award and available for payment is $344,795,504 (this is an increase of $28,817,712). Any work performed in excess thereof shall be at the Project Awardee’s risk. The Project Awardee shall notify the CMF if at any time the Project Awardee has reason to believe that the costs accrued in the next [***] ([***]) days will exceed [***] percent ([***]%) of the current total authorized funding. Such notice should specify the estimate of additional funds required, along with the associated remaining tasking and timeframe. The Project Awardee is not obligated to continue performance under this Project Award (including actions under the Termination clause of the RRPV Base Agreement) or otherwise incur costs in excess of the amount identified in this clause.

The USG shall provide initial funding for the Project Award on a firm fixed price basis at the time of award that will fund trial preparation activities (Milestone 2). When the USG and Vaxart have mutually determined that the trial shall further proceed, the USG shall provide additional funding on an expenditure-based basis during the period of performance of the Project Award to support Vaxart’s performance of the requirements set forth in the Project Award. The USG shall provide such additional funding in incremental amounts based upon Vaxart’s continued fulfillment of requirements of the Project Award commensurate with the payment terms established in the Project Award.

20. Indirect Rates

The parties agree that the indirect rates for this Project Award will not exceed the percentages set forth in the table below. Therefore, expenditures reimbursed by the Government, through the CMF, to the Project Awardee under this Project Award shall not exceed the costs based on the below rates even in the event that actual rates exceed final approved indirect rates. The rates utilized are final for the remainder of the contract. BARDA will not re-negotiate or allow for any adjustment to these rates throughout the duration of the project or following the contract’s conclusion.

Except as provided herein, all Terms and Conditions of the referenced RRPV Base Agreement, Project Award and preceding modifications remain unchanged and in full force and effect.

The Project Awardee is required to sign this document and return to Advanced Technology International to finalize this action.

Attachment A Statement of Work

(Incorporated via Modification No. 07. Attachment A is replaced in its entirety.)

**RPP#: **24-04-NGVx

**Project Identifier: **RRPV24-04-NGVx-003

**Project Title: **Oral Mucosal Vaccine for SARS-CoV2 Protection

**RRPV Member Organization Name: **Vaxart, Inc.

**Primary Place of Performance: **170 Harbor Way, Suite 300, South San Francisco, CA 94080

Vaxart Biosciences, Inc. (“Vaxart”) is a development-stage biotechnology company with a pipeline of biologics across multiple therapeutic classes. Vaxart's platform technology makes it possible to administer vaccines in a thermo-stable tablet form, allowing for rapid deployment in mass vaccination programs, without the large logistical requirements and significant medical waste of conventional frozen vaccines. The vaccines are designed to trigger strong mucosal IgA and T-cell responses, as well as systemic antibodies. The technology is based on a non-replicating adenoviral vector with a molecular adjuvant that enhances antigen immune responses in the human intestine, the site of tablet release.

This project will compare Vaxart’s updated COVID-19 vaccine candidate to an mRNA comparator to evaluate efficacy for symptomatic and asymptomatic disease, systemic and mucosal immune induction, and adverse events.

The objective of this project is to complete a phase 2b clinical trial, comparing Vaxart’s Covid-19 candidate vaccine to an approved mRNA COVID-19 vaccine. Vaxart has divided the program into two phases. Phase 1 includes the execution of a Phase 2b clinical trial comparing Vaxart’s vaccine candidate and an mRNA vaccine comparator for efficacy, immune induction, and safety. Phase 2 includes further analysis to characterize the durability of the immune responses initially characterized by tracking mucosal samples from vaccinated individuals for a year and assessing cross-reactivity over time.

Phase 1: Clinical Trial Execution for Phase 2b Clinical Trial

Vaxart shall execute a Phase 2b clinical trial in approximately 5,000 individuals comparing Vaxart’s KP.2 vaccine candidate and an mRNA KP.2 vaccine comparator for efficacy, immune induction, and safety. The clinical trial will begin with a sentinel cohort of 400 individuals using Vaxart’s XBB vaccine and an mRNA XBB comparator.

Specifically, Vaxart will:

Vaxart will manufacture new KP.2 lots as described under Task Area 5 (1.5), CMC, to support the approximately 5,000-participant arm of the study.

Additional Characterization of Immune Responses by Vaxart

As shown in the table below, Vaxart will expand on the durability of the immune responses initially characterized by tracking sera and mucosal samples from vaccinated individuals for a year and assess cross-reactivity over time via MSD antibody assay. Vaxart will also conduct B-cell flow cytometry assays (referred to as Phase 2 later in the SOW) and T-cell AIM assays, as well as support central assay conduct of assays, and subsequent analysis and report generation of all immune assay data.

Assays to be conducted by Vaxart:

Phase 1: Clinical Trial Execution for Phase 2b Clinical Trial (WBS 1)

Vaxart shall execute a Phase 2b clinical trial in approximately 5,000 individuals comparing Vaxart’s vaccine KP.2 candidate and an mRNA KP.2 vaccine comparator for efficacy, immune induction, and safety. The clinical trial will begin with a sentinel/safety cohort of 400 individuals using Vaxart’s XBB vaccine and an mRNA XBB comparator.

Task Area #1 – Program Management (WBS 1.1)

Vaxart’s program management activities will follow procedures described in the Project Management Institute Project Management Book of Knowledge (“PMBOK©”). These activities align with requirements established by BARDA. Consistent with those requirements, the primary objective of program management is to ensure that the activities and outputs that result are delivered on time, within scope and budget, and meet applicable quality standards.

Vaxart will undertake all of the required program management activities necessary to complete Phase 1 and Phase 2 of this project.

Task Area #2 – Analytical (WBS 1.2)

Vaxart’s analytical activities encompass those activities to be performed to collect, test (internally or at BARDA-contracted lab), and report on samples taken from participants in both the XBB and KP.2 cohorts in the Phase 2b trial. All Vaxart conducted (whether directly or via sub-contract) immunogenicity assay work will be done on samples from the KP.2 cohort using appropriately developed assays and in accordance with SOPs (see details for appropriate development level in note at the end of the SOW).

Vaxart will provide serum and PBMC samples to BARDA for analysis at a BARDA-designated testing facility (WBS 1.2.1); Vaxart will also be responsible for conducting specified additional assays.

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BARDA and Vaxart will characterize immune responses at mucosal surfaces according to the schedule detailed in the protocol. (WBS 1.2.2)

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Vaxart will determine the efficacy of Vaxart’s vaccine candidate and the mRNA comparator vaccine against symptomatic and asymptomatic COVID-19 infection. (WBS 1.2.3)

*Requirement of Vaxart-supported assay testing:

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*BARDA notes that while the DMID guidelines call for exploratory assays in Phase 2 trials to be ‘optimized’, these MSD assays need to be qualified/fit-for-purpose to support data interpretation in alignment with what has been done for all other MSD assays in the trial.

**Note the SOPs and Fit-for-Purpose/Qualification Report will be needed for each sample matrix

***Costs for Fit-for-Purpose/Qualification development will be budgeted accordingly across 1.2.1 and 1.2.2.

Task Area #3 – Clinical (WBS 1.3)

Vaxart’s clinical efforts encompass all activities and tasks to be performed in the execution of the Phase 2b clinical trial from study initiation of XBB safety lead-in group of 400 participants to delivery of the CSR with approximately 5,000 participants completing the trial with KP.2. Study enrollment will be paused between strain change to allow safety data review of the lead-in cohort by the DSMB committee, as well as FDA and BARDA, before re-starting.

Vaxart will complete all of the activities required for clinical trial site start-up. BARDA representatives will be included in all key discussions with the CRO for clinical trial site start-up to include but not limited to demographics, recruitment, enrollment, and retention. (WBS 1.3.1)

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Vaxart will enroll eligible volunteers first in the safety lead-in cohort (400) and, upon successful DSMB 30-day safety review along with FDA and BARDA approval, then in the follow-on approximately 5,000 participant full enrollment cohorts, and ensure that they are randomized and assigned to a treatment group. (WBS 1.3.2). The Project Awardee agrees that the Phase 2b clinical trial will be conducted in alignment with Attachment B, “Key Tenets”. Awardees must provide a Representative Enrollment Plan that includes enrollment of participants in both the lead-in cohort of 400 participants and the full enrollment of approximately 5,000 participants based on the agreed-upon plan. Demographics targets will align with the 2020 US Census Data provided here:

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*Current US Census data refers to 2020 US Census data = 2023 US Census Data; U.S. Census Bureau QuickFacts: United States; accessed 12/12/2024

**2020/2023 US Census data does not include reporting for Not Hispanic or Latino; however, OMB and FDA include reporting for this category; comparison to 2020/2023 US Census data is N/A

***2020/2023 US Census data includes reporting for Two or More Races; however, OMB and FDA do not include reporting for this category; individual race categories should be reported instead according to participant selections

**** Program requirement of at least 25% elderly (>=65 years) participants enrolled.

Activation of each enrollment milestone (MS 50 – 50.2) will not initiate without written authorization from BARDA (PAR or Alt PAR).

Potential participants will undergo pre-screening including an initial evaluation to determine their eligibility, including: (WBS 1.3.2.1)

Participants will be randomized using the Interactive Web Response System (IWRS) which will assign unique identification numbers and determines treatment allocation based on the randomization schedule.

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(WBS 1.3.2.3) Dosing data will be updated in EDC within the standard turnaround time for data entry of 5 business days from visit completion.

Vaxart will complete all the activities required to ensure clinical conduct of the trial. (WBS 1.3.3)

As recommended by the FDA, a Drug Safety Monitoring Board (DSMB) will convene and review safety data of the initial 400 participants in the safety-lead in cohort after they complete Day 31 (Visit 3). The raw data and the DSMB recommendation will then be submitted to BARDA and the FDA (WBS 1.3.3.3)

Vaxart will oversee routine and for-cause monitoring visits during the conduct of the clinical trial to ensure compliance with the study protocol, regulatory requirements, and Good Clinical Practice (GCP) guidelines. (WBS 1.3.4)

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Monitoring or trip reports will be prepared by Clinical Research Associates (CRAs) after conducting routine monitoring visits to research sites. These reports will include a detailed account of the visit, including site activities, data verification, source document review, and any findings or discrepancies identified. They will document participant safety assessments, compliance with the study protocol and regulatory guidelines, and any issues or concerns raised during the visit. (WBS 1.3.4.2)

Vaxart will undertake a comprehensive clinical data management program that will include the collection, validation, and analysis of participant data to ensure its accuracy, completeness, and confidentiality. (WBS 1.3.5)

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Vaxart will complete database lock in a stepwise fashion which first includes freezing data for the XBB topline report and XBB full analysis report, followed by data cleaning (soft lock) for KP.2 prior to full database lock (hard lock) and completion of the KP.2 CSR. The process of finalizing and freezing the study database is to prevent further modifications to the data. (WBS 1.3.6)

The Data Safety Management Board (DSMB) will perform planned safety reviews monthly, aggregate data reviews quarterly and ad hoc safety reviews as deemed necessary. Data displays for any DSMB review will be generated by the appropriate blinded or unblinded statistical team. The operations of the DSMB will be specified in the DSMB charter. (WBS 1.3.7)

Vaxart will work with the CRO to generate the final reports and close-out the trial as described below (1.3.8)

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Task Area #4 – Regulatory (WBS 1.4)

Vaxart will prepare FDA submissions, keep track of relevant legislation, advise on legal and scientific requirements and limitations, and provide regulatory support for the evaluation of data for this study.

**Task Area #5 – CMC (WBS 1.5) - Trial Material Manufacturing, Acquisition, Packaging & Distribution **Vaxart will complete all activities and GMP documentation, ensuring that clinical trial material will be ready to support the 400-participant sentinel study (XBB) and the approximately 5,000 participant Ph2b head-to-head clinical trial with an mRNA comparator targeting the KP.2 COVID variant. Activation of milestones for comparator vaccine purchase (MS 113.1 & 113.2) and kitting (MS 116.1 & 116.2) will not proceed without written authorization from BARDA (PAR or Alt PAR).

Vaxart Trial Material Manufacturing & Packaging (1.5.1)

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CTM Distribution & Logistics (1.5.2)

PHASE 2: Additional Characterization of Immune Responses

Vaxart will expand on the durability of the immune responses initially characterized by tracking mucosal samples from vaccinated individuals for a year and assess cross-reactivity over time.

Task Area #1 – Analytical (WBS 2.1)

Vaxart, in partnership with University of Washington (UW), will conduct B-cell flow cytometry as part of ‘future use’ testing to determine the changes to the B cell memory pool in the subpopulation of participants with samples collected on days 1 and 8 using PBMC-EDTA. All assay work will be done using appropriately developed assays in accordance with SOPs (see details for appropriate development level in note at the end of the SOW) and referenced in 1.2.1. (WBS 2.1)

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*Deliverables are not considered 'final' until approved by the PAR or Alt PAR.

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1 Final Indirect rates have been agreed-to by Vaxart and Government as detailed in the Project Agreement.

*RESERVE Note: Additional funding available only upon written request with acceptable technical justification and Government approval (PAR/Alt PAR & OTAO).

**WBS activities may not be initiated without PAR/Alt PAR approval

Vaxart has filed broad domestic and international patents covering its proprietary technology and creations for oral vaccination using adenovirus and TLR3 (US patents 7,879,602 and 8,222,224). Vaxart has also filed for patent protection on their COVID-19 vaccine candidates. All intellectual property is fully owned by Vaxart, without any encumbrances.

Vaxart anticipates that it will utilize intellectual property (including patented inventions) in the performance of any contract that either has been developed at private expense (and in which Vaxart has ownership in the case of patented invention pursuant to FAR 52.227-11 or data pursuant to FAR 52.227-14), developed by a third-party (in which Vaxart has appropriate license rights) or pursuant to a prior government contract (in which case Vaxart has ownership rights as determined by that contract). Vaxart will provide a more detailed statement of rights in intellectual property for government review and approval (including any declarations of rights in intellectual property by Vaxart’s subcontractors) and does not anticipate any impediments in Vaxart’s ability to develop the vaccine technology based upon intellectual property that will be utilized in performance.

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