10-Q: Arcturus Q2: KOSTAIVE Gains EU Approval, Pipeline Advances

Arcturus Therapeutics reported a reduced net loss in Q2 2025, driven by lower R&D expenses, as its COVID-19 vaccine KOSTAIVE received EU marketing authorization and key therapeutic programs advanced.

Summary

• Net loss significantly decreased to $(9.180) million for the three months ended June 30, 2025, compared to $(17.216) million for the same period in 2024.
• Total revenue decreased by 43% to $28.301 million in Q2 2025 and by 34% to $57.683 million for the six months ended June 30, 2025, primarily due to less revenue from supply agreements and less amortization as KOSTAIVE transitions from a development program to the commercial phase.
• Research and development expenses decreased by 50% to $29.579 million in Q2 2025 and by 43% to $64.471 million for the six months ended June 30, 2025, driven by lower manufacturing and clinical costs for vaccine programs.
• KOSTAIVE (ARCT-154), the company's self-amplifying RNA COVID-19 vaccine, received marketing authorization in Europe in February 2025 and a Marketing Authorization Application was filed in the UK in June 2025.
• Positive multiple dosing data was announced for ARCT-810 (LUNAR-OTC) from two Phase 2 studies, showing significant decreases in glutamine levels and increased relative ureagenesis function (RUF).
• The Phase 2 study for ARCT-032 (LUNAR-CF) initiated dosing in December 2024, with enrollment ongoing.
• A material weakness in internal control over financial reporting related to information technology general controls (ITGCs) continues to exist as of June 30, 2025, with remediation efforts expected to be completed in fiscal year 2025.
• Cash and cash equivalents, including restricted cash, totaled $253.4 million as of June 30, 2025.

Sentiment

Score: 6

Explanation: While revenue declined and a material weakness persists, the significant reduction in net loss, multiple regulatory approvals/filings for KOSTAIVE, and positive clinical advancements in key pipeline programs (ARCT-810, ARCT-032, ARCT-2304) indicate strong operational progress and validation of their platform, offsetting the financial headwinds and internal control issues. The arbitration with CSL Seqirus is a concern but not necessarily a deal-breaker given the ongoing collaboration commitment.

Positives

• Net loss significantly improved to $(9.180) million in Q2 2025 from $(17.216) million in Q2 2024, and to $(23.256) million for 6M 2025 from $(44.033) million for 6M 2024.
• KOSTAIVE (ARCT-154) received marketing authorization in Europe in February 2025, expanding its global reach after Japan approval.
• A Marketing Authorization Application for KOSTAIVE was submitted to the UK MHRA in June 2025.
• Positive multiple dosing data for ARCT-810 (LUNAR-OTC) Phase 2 studies showed significant decreases in glutamine levels (p-value = 0.016 in European study; p-value = 0.004 in U.S. study) and increased relative ureagenesis function (RUF) (p-value = 0.026), with two of three participants achieving RUF > 50%.
• ARCT-810 was generally safe and well tolerated in single and multi-dose studies, with no serious infusion-related reactions observed using the improved 3-hour IV regimen.
• ARCT-032 (LUNAR-CF) Phase 2 study initiated dosing in December 2024 and enrollment is ongoing, advancing the rare disease therapeutic pipeline.
• ARCT-2304 (LUNAR-H5N1) received Fast Track Designation from the FDA in April 2025, designed to expedite its development and review process.
• Achieved $20.0 million in development milestones related to the CSL Collaboration Agreement during Q2 2025.
• Cash and cash equivalents, including restricted cash, totaled $253.4 million as of June 30, 2025, providing liquidity for at least the next twelve months.

Negatives

• Total revenue decreased by 43% to $28.301 million for the three months ended June 30, 2025, compared to $49.859 million for the same period in 2024.
• Total revenue decreased by 34% to $57.683 million for the six months ended June 30, 2025, compared to $87.871 million for the same period in 2024.
• Net cash used in operating activities increased to $(40.893) million for the six months ended June 30, 2025, from $(35.699) million for the same period in 2024, primarily due to working capital changes including increased vendor payments.
• A material weakness in internal control over financial reporting related to information technology general controls (ITGCs) continues to exist as of June 30, 2025.
• An arbitration was initiated against CSL Seqirus on May 30, 2025, seeking payment of a milestone, which CSL Seqirus contends it does not have a current obligation to pay.
• Interest income decreased by 38% to $2.567 million in Q2 2025 and 35% to $5.339 million in 6M 2025, primarily due to lower interest rates and a reduced cash balance.

Risks

• Ability to remain in compliance with collaboration agreements, including with CSL Seqirus, and timely receipt of upfront, royalty, and other payments thereunder.
• Continued compliance by strategic partners and collaborators under existing agreements.
• Arrangements with private and governmental entities are subject to termination for convenience by counterparties.
• Ability to remain in compliance with stringent requirements of current and potential government contracts, such as those with BARDA.
• Uncertainty regarding the initiation, design, cost, timing, progress, enrollment, and results of research and development activities, preclinical studies, and clinical trials.
• Uncertainty regarding the potential safety, immunogenicity, efficacy, or regulatory approval of any product candidates.
• Likelihood that preclinical or clinical data will be predictive of future clinical results or efficacy or safety of a product candidate.
• Likelihood or timing of any regulatory approval, and whether marketing approval in Japan will be predictive of future marketing approvals in other countries or for other product candidates.
• Ability to obtain and maintain regulatory approval of product candidates, and any related restrictions, limitations, and/or warnings in the label of an approved product candidate.
• Success of competing therapies that are or may become available.
• Ability to obtain and maintain intellectual property protection for product candidates.
• Performance of third-party suppliers and manufacturers, including the ability to implement and scale-up manufacturing levels as necessary.
• Strategic alliance partners' election to pursue development and commercialization of any programs or product candidates subject to collaboration and license agreements.
• Ability to attract collaborators with relevant development, regulatory, and commercialization expertise.
• Ability to avoid, settle, or be victorious at costly litigation with shareholders, former executives, or others.
• Ability to obtain and deploy funding for operations and to efficiently use financial and other resources.
• Ability to continue as a going concern.
• Accuracy of estimates regarding future expenses, future revenues, cash flows, capital requirements, need for additional financing, and possible sources of revenue.
• Actual results could differ materially from forward-looking statements due to various factors.
• Control weaknesses are not considered remediated until new internal controls have been operational for a period of time, are tested, and management concludes that these controls are operating effectively.
• The outcome of any legal proceedings or claims, regardless of the merits, is inherently uncertain, and assessing the likelihood of loss and any estimated damages is difficult and subject to considerable judgment.

Future Outlook

The company anticipates continued losses for the foreseeable future, expecting them to increase as product candidates advance through development and regulatory approvals towards commercialization. Future funding requirements are difficult to forecast and depend on factors such as vaccine candidate development, milestone achievements, manufacturing network expansion, regulatory approvals, and potential litigation. The current cash position is expected to meet anticipated cash requirements for at least the next twelve months, assuming no significant unforeseen expenses and continued partner funding. Additional capital will be required long-term, potentially through equity/debt financings or new partnerships. Payroll and benefits costs are not expected to increase over the next twelve months due to reduced share-based compensation expense, and facilities and equipment expenses are also not expected to increase.

Management Comments

• We are a commercial messenger RNA medicines company focused on the development of liver and respiratory rare disease therapeutics and infectious disease vaccines.
• We developed the worlds first approved self-amplifying messenger RNA (sa-mRNA) vaccine, KOSTAIVE (KOSTAIVE).
• Sales of KOSTAIVE began in Japan in October 2024, marking our transition to a commercial stage company.
• The approval of KOSTAIVE in Europe, as well as the approval in Japan, are significant milestones, which further validate our LUNAR and STARR platforms, as well as sa-mRNA more generally as a meaningful modality.
• Management does not believe that the deficiencies [in internal control over financial reporting] had an adverse effect on our reported operating results or financial condition, and management has determined that the financial statements and other information included in this report and other periodic filings present fairly in all material respects our financial condition and results of operations at and for the periods presented.
• We are committed to making the necessary changes and improvements to our system of controls to address the material weakness in internal control over financial reporting described above.
• We expect to complete the remediation activities [for material weakness] in the fiscal year 2025.
• We expect to continue to incur additional losses in the long term, and we will need to execute on the remaining milestones within the CSL Collaboration Agreement, raise additional debt or equity financing or enter into additional partnerships to fund development.
• Our ability to transition to profitability is dependent on regulatory approvals and subsequent sales of KOSTAIVE, executing on milestones within the CSL Collaboration Agreement and identifying and developing other successful mRNA drug and vaccine candidates.
• If we are not able to achieve planned milestones or incur costs in excess of our forecasts, we will need to reduce discretionary spending, discontinue the development of some or all of our programs, which will delay part of our development programs, all of which will have a material adverse effect on our ability to achieve our intended business objectives.

Industry Context

Arcturus Therapeutics operates at the forefront of mRNA medicine, a rapidly evolving field with significant potential for both infectious disease vaccines and rare genetic disorder therapeutics. The approval of KOSTAIVE in Japan and Europe positions the company as a pioneer in self-amplifying mRNA (sa-mRNA) vaccines, differentiating it from conventional mRNA vaccines (e.g., Pfizer/BioNTech, Moderna) by potentially offering longer-lasting and broader immune responses at lower doses. This commercialization milestone, alongside ongoing clinical advancements in influenza and H5N1 vaccines, aligns with the broader industry trend of expanding mRNA applications beyond COVID-19. The company's focus on rare diseases like OTC deficiency and cystic fibrosis also places it in a high-unmet-need segment, where novel genetic therapies are highly sought after. The ongoing arbitration with CSL Seqirus highlights the complexities of large-scale pharmaceutical collaborations, a common challenge in the industry.

Comparison to Industry Standards

• KOSTAIVE (ARCT-154) is highlighted as the 'world's first approved and commercially available self-amplifying RNA (sa-mRNA) vaccine,' setting a new benchmark in the mRNA vaccine space and differentiating it from established conventional mRNA vaccines like those from Pfizer/BioNTech (Comirnaty) and Moderna (Spikevax).
• The Phase 1 study of ARCT-2138 (seasonal influenza vaccine) demonstrated immunogenicity in both young and older adults with doses as low as 2 µg, and was tolerable across a dose range of 2 to 20 µg. This positions it against other mRNA influenza vaccine candidates in development by companies like Moderna and Pfizer/BioNTech.
• The positive Phase 2 data for ARCT-810 (LUNAR-OTC) showing significant glutamine reduction and increased Relative Ureagenesis Function (RUF) in OTC deficient patients suggests a clinically meaningful improvement, positioning it against other investigational therapies for rare metabolic disorders, which often have limited treatment options.
• The Fast Track Designation for ARCT-2304 (LUNAR-H5N1) from the FDA indicates its potential to address a significant global health risk, aligning with global pandemic preparedness efforts and potentially accelerating its development compared to standard pathways.

Corporate Governance

Legal Proceedings

• Arbitration initiated on May 30, 2025, against CSL Seqirus before the International Chamber of Commerce, seeking payment of a milestone under the CSL Collaboration Agreement based on EU marketing authorization for KOSTAIVE. CSL Seqirus submitted an Answer on July 25, 2025, contending no current obligation to pay. The arbitration is ongoing.
• The company may be involved in various legal proceedings and subject to claims that arise in the ordinary course of business, including those related to governmental inquiries, intellectual property, and commercial relationships.

Related Party Transactions

• The company has an equity-method investment in ARCALIS, Inc., a joint venture with Axcelead, Inc. The carrying value of this investment remained at zero as of June 30, 2025. ARCALIS, Inc. has also been approved as a manufacturing site for KOSTAIVE in Japan.

Stakeholder Impact

• Shareholders: Potential dilution from future equity financings; impact from ongoing legal dispute with CSL Seqirus; validation of platform technology through regulatory approvals and clinical progress; financial performance (reduced net loss but decreased revenue).
• Employees: Payroll and benefits costs are not expected to increase over the next twelve months due to reduced share-based compensation expense; ongoing remediation efforts for ITGCs.
• Customers (CSL Seqirus, Meiji, BARDA): Ongoing collaboration and development activities; dispute with CSL Seqirus over milestone payment.
• Patients (COVID-19, Influenza, H5N1, OTC, CF): Progress in vaccine development (KOSTAIVE approvals, Fast Track for H5N1); positive clinical data for ARCT-810 (OTC); ongoing Phase 2 for ARCT-032 (CF) offers hope for new therapeutic options.
• Suppliers/Manufacturers: Lower manufacturing costs for vaccine programs noted; performance of third-party suppliers and manufacturers is a risk factor.
• Creditors (Wells Fargo): $50.0 million revolving credit line available, collateralized by $55.0 million in cash, extended to April 2026.

Next Steps

• Continue to conduct and advance research and discovery programs.
• Continue development activities for LUNAR-COV19 and LUNAR-FLU programs under the CSL Seqirus collaboration.
• Continue to enroll participants in the U.S. Phase 2 study for ARCT-810 (LUNAR-OTC).
• Continue enrollment in the Phase 2 study for ARCT-032 (LUNAR-CF).
• Monitor the effectiveness of remediation measures for the material weakness in internal control over financial reporting, with completion expected in fiscal year 2025.
• Evaluate the impact of the One Big Beautiful Bill Act (OBBBA) tax law changes on financial condition and results of operations, with impact to be included in Q3 2025 financial statements.
• Seek additional capital through equity and/or debt financings, collaborative or other funding arrangements, or other sources of financing when and as needed.
• Continue to collect data from various ongoing studies for KOSTAIVE (COVID-19 vaccine).
• Continue to progress the LUNAR-H5N1 program under the BARDA award.

Key Dates

Recommendation

The company demonstrates significant progress in its pipeline with regulatory approvals for KOSTAIVE in Europe and positive clinical data for ARCT-810, validating its mRNA platform. This operational strength is a positive. However, the substantial decline in revenue, increased cash burn from operations, and the ongoing material weakness in internal controls present financial and operational concerns. The arbitration with a key partner, CSL Seqirus, adds an element of uncertainty to future collaboration revenues. While the long-term potential of their technology is evident, the current financial performance and internal control issues suggest a 'hold' position until there is clearer evidence of revenue stabilization, resolution of the internal control weakness, and a positive outcome from the CSL Seqirus dispute.

Keywords

mRNA, self-amplifying RNA, sa-mRNA, LUNAR, STARR, KOSTAIVE, ARCT-154, ARCT-810, ARCT-032, ARCT-2138, ARCT-2304, COVID-19 vaccine, Influenza vaccine, H5N1, Ornithine Transcarbamylase Deficiency, Cystic Fibrosis, Rare Disease Therapeutics, Infectious Disease Vaccines, Biotechnology, Pharmaceuticals, Clinical Trials, Regulatory Approval, SEC Filing, 10-Q, Financial Results, Biopharma, Drug Development, Vaccine Development, Gene Therapy