Arcturus Completes ARCT810 Phase 2 Enrollment and Dosing

Arcturus Therapeutics (NASDAQ: ARCT ) released second-quarter financial results and hosted an earnings call on Thursday. Read the complete transcript below. This content is powered APIs. For comprehensive financial data and transcripts, visit View the webcast at Summary Arcturus Therapeutics reported ongoing progress in its rare disease pipeline, particularly with ARCT032 for cystic fibrosis and ARCT810 for OTC deficiency, with significant milestones such as Phase 2 study advancements and enrollment completion.

The company regained global rights to its self-amplifying mRNA platform and COVID vaccine product, Kostaive, following the conclusion of its collaboration with CSL Seqirus, enhancing strategic control over its vaccine portfolio. Financial performance saw a decrease in revenue compared to the previous year due to the termination of the CSL collaboration; however, the company maintains a strong cash position and runway, bolstered by a $12 million payment from CSL and strategic partnerships.

Future guidance includes a decision on moving ARCT032 to Phase 3 expected in Q4 2026, with continued data collection and regulatory discussions for the OTC program, and potential commercial and partnership opportunities for the vaccine portfolio. Management emphasized the unique opportunity to set new standards for success in its CF program and highlighted strategic initiatives to leverage regained vaccine rights for future commercialization and partnerships. Full Transcript OPERATOR Hello and welcome everyone joining today's Arcturus Therapeutics second quarter 2026 earnings call. At this time, all participants are in a listen-only mode.

Later, you will have an opportunity to ask questions during the question-and-answer session. To register to ask a question at any time, please press star-1 on your telephone keypad. Please note this call is being recorded, and we are standing by should you need any assistance. It is now my pleasure to turn the meeting over to Neta Safazada, Vice President, Head of Investor Relations, Public Relations and Marketing.

Please go ahead. Neta Safazada, Vice President, Head of Investor Relations, Public Relations and Marketing Thank you, operator. Good afternoon and welcome to Arcturus Therapeutics quarterly financial update and pipeline progress call. Today's call will be led by Joe Payne, our President and CEO; Dr.

Alan Cohen, our Chief Medical Officer; and Dennis Mulroy, our Chief Financial Officer. Dr. Pad Chivukula, our CSO and COO, will join them for the Q&A session. Before we begin, I would like to remind everyone that the statements made during this call regarding matters that are not historical facts are forward-looking statements within the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Forward-looking statements are not guarantees of performance. They involve known and unknown risks, uncertainties, and assumptions that may cause actual results, performance, and achievements to differ materially from those expressed or implied by these statements. Please see the forward-looking statement disclaimer in the company's press release issued earlier today, as well as the risk factors section in our most recent Form 10-K and in subsequent filings with the SEC. In addition, any forward-looking statements represent our views only as of the date such statements are made.

Arcturus specifically disclaims any obligation to update such statements, and with that, I will now turn the call over to Joe. Joe Payne, President and CEO Thank you, Neta, and it's good to be with you again, everybody. The second quarter of 2026 was marked by continued execution across our rare disease pipeline and important strategic developments for Arcturus' vaccine franchise. Today I'll provide updates on our rare disease programs ARCT032 and ARCT810 and summarize today's good news regarding our vaccine enterprise.

I will then turn the call over to Alan for additional clinical updates and to Dennis to review our financial results. Starting with ARCT032, our inhaled mRNA therapeutic candidate for CF. During the quarter, our Phase 2 study continued to advance on schedule, with active screening and enrollment ongoing across sites in the United States, Israel, and Turkey. These international sites are important for our recruitment strategy given the higher prevalence of individuals living with Class I CF in Israel and Turkey.

As a reminder, Cohort 4 is evaluating 10 mg of ARCT032 administered daily by inhalation over a 12-week treatment period. The study is monitoring for safety and evidence of early clinical benefit, including pulmonary function measures such as percent predicted FEV1 and lung clearance index, or LCI. In addition, quality-of-life measures and high-resolution CT imaging data are being collected. The decision to advance our CF program into Phase 3 is expected in the fourth quarter, or Q4 2026.

If Arcturus decides to proceed into a Phase 3 trial, this decision triggers additional and very meaningful contributions from Thermo Fisher, including manufacturing support, clinical research, and related services. Turning to ARCT810, this is our mRNA therapeutic candidate for ornithine transcarbamylase deficiency, or OTC deficiency. We are pleased to update the market today that we've completed enrollment in our ongoing Phase 2 study and all enrolled subjects have completed study drug dosing.

This represents an important operational milestone for our OTC program, and with the dosing phase of the study completed, our team is now evaluating the Phase 2 clinical data along with the supplementary data requested by the FDA in a Type C meeting earlier this year. These data will inform upcoming regulatory discussions across both adult and pediatric development. We expect to communicate the Phase 2 clinical study data later this year in Q3 2026. Concurrent with the data readout, we will provide additional details regarding the regulatory path forward for our OTC deficiency program.

Now on to our vaccine division. Today we announced the conclusion of our self-amplifying mRNA collaboration with CSL Seqirus, and on behalf of Arcturus, I wanted to express sincere gratitude to the outstanding team at CSL. They've been a great partner to help shepherd this first-in-class, next-generation self-amplifying mRNA technology to where it is today: a validated platform with approvals in over 30 countries. We are pleased to regain global rights to our commercial COVID vaccine product Kostaive and to our self-amplifying mRNA platform.

Having strategic control of this validated vaccine platform is an exciting opportunity for our company. The Arcturus self-amplifying mRNA platform is validated. It's proven to be efficacious, with an immune response that is durable and superior in comparative studies. It's been reviewed by several regulatory agencies to be safe and well tolerated.

The manufacturing process is commercial-ready, scalable, fast, with lower COGS attributed to a significantly lower dynamic dose level. Several global regulatory agencies have reviewed and approved Arcturus' self-amplifying mRNA vaccine platform as represented by Kostaive, which has been approved for licensure in Europe, Japan, and more recently the United Kingdom, with the regulatory path forward into the United States also clearly understood. The Arcturus vaccine platform is pandemic-ready. S.

government is keenly aware of this next-generation self-amplifying mRNA platform. It is likely not a matter of if, but rather a matter of when this platform will be called upon to address future epidemics of infectious disease. Under the agreement, Arcturus regained global rights to Kostaive and the broader infectious disease vaccine portfolio, including seasonal influenza, pandemic influenza, RSV, and EBV vaccine programs. The agreement also resolves the arbitration related to the European regulatory approval milestone payment.

CSL Seqirus wired a one-time cash payment of $12 million to Arcturus, and Arcturus is released from liabilities, including those associated with an R&D credit with an aggregate value of approximately $16 million. With strategic control of the portfolio returned to Arcturus, we are evaluating opportunities to maximize its future value, including further commercialization and partnering pathways. And with that, I'll turn the call over to Alan for a more detailed update on our clinical programs. Alan H.

Cohen, MD — Chief Medical Officer & Executive Vice President Thank you, Joe, and good afternoon everyone. From a clinical development perspective, the second quarter represented meaningful progress for both ARCT032 and ARCT810. Beginning with our CF program, ARCT032, our ongoing Phase 2 study continues to enroll people living with cystic fibrosis who have Class I mutations. Enrollment remains on schedule, with active screening and enrollment underway across sites in the United States, Israel, and Turkey.

The study is designed to evaluate daily inhaled dosing of 10 mg over a 12-week treatment period. It continues to assess safety as well as evidence of early clinical benefit, including pulmonary function measures such as changes in percent predicted FEV1 and lung clearance index, quality-of-life measures, and high-resolution CT scan imaging. One important development this quarter was the expansion of screening and enrollment activities beyond the United States into the Eastern Mediterranean region.

Israel and Turkey are geographies with a high prevalence of individuals with CF Class I or null mutations, which will meaningfully support our recruitment efforts and efficiencies for this study. Unlike the United States, where up to 10% of people with CF are ineligible for modulators due to null mutations, up to 30% to 40% of people with CF have null mutations and are eligible for consideration of enrollment in our ARCT032 study from Turkey and Israel, respectively. Clinical execution remains on schedule, and we are laser focused on generating the data needed to support the Phase 3 decision expected in Q4 2026.

Turning to our OTC deficiency program, ARCT810, during the quarter we completed enrollment of the ongoing Phase 2 study, and all enrolled subjects completed study drug dosing. This is an important operational milestone and allows us to now focus on evaluating the supplementary data generated from the enrolled study population. We remain grateful for the continuing support, ongoing encouragement, and strong engagement on behalf of our ARCT810 OTC deficiency study by the patients, their families, and the rare disease care community. Thank you for all your collective help and interest in our development program.

Our current efforts are focused on data review, preparation for upcoming regulatory interactions, and planning for an end-of-Phase 2 meeting regarding the path forward across both adult and pediatric development. We expect to communicate both the data and regulatory plan for the OTC deficiency program in Q3 2026. Across both our rare disease programs, our focus remains on disciplined clinical execution, high-quality data generation, and productive regulatory engagement to support efficient development decisions. With that, I will turn the call over to Dennis.

Dennis Mulroy — Chief Financial Officer Thanks, Alan, and good afternoon everyone. Our press release issued earlier today includes financial statements for the three and six months ended June 30, 2026, and provides a summary and analysis of year-over-year performance. Please also reference our Form 10-Q for more details on our financial performance. 3 million over the first half of 2026.

7 million in the comparable periods last year. Lower revenue was recognized under the CSL collaboration as Arcturus progressed towards termination of the agreement and regaining rights to Kostaive and its broader infectious disease vaccine portfolio. 5 million for the corresponding periods in 2025. The decreases were primarily driven by lower research and development spending, including reduced salaries, wages, benefits, and facilities costs, as the company continues to advance its CF and OTC programs while maintaining its disciplined approach to capital allocation.

7 million in the comparable periods last year. Overall, general and administrative expenses remained relatively consistent across periods, with a slight quarter-to-quarter increase due to legal fees, partially offset by reduced spending in salaries, wages, benefits, and facilities costs. We remain focused on disciplined execution and capital allocation as we advance our rare disease programs. The CSL Seqirus termination and settlement agreement strengthens our financial position as we regain control of those assets.

And the Thermo Fisher collaboration funds and supports the execution of late-stage development of our CF program. We continue to maintain a strong balance sheet and cash runway of over two and a half years through year-end 2028, allowing the company to reach important clinical and regulatory milestones for its rare disease pipeline. With that, I'll pass the call back to Joe. Joe Payne, President and CEO Thank you, Dennis.

Arcturus continues to execute across our rare disease therapeutics portfolio while strengthening the long-term strategic position of the company. With enrollment progressing in our Phase 2 ARCT-032 study, and completion of enrollment and dosing of ARCT-810, and the return of strategic control of our vaccine portfolio, we remain focused on advancing important clinical, regulatory and corporate milestones through the remainder of 2026. And with that, let's turn the call over to the operator for questions. OPERATOR Thank you.

If you'd like to ask a question, press star one on your keypad. To leave the queue at any time, press star two. Once again, that is star one to ask a question. And we'll take our first question from Lily Noso with Lyric Partners.

Please go ahead. Your line is now open. Lily Noso, Analyst at Lyric Partners Hi, good afternoon. Thank you for the update on the quarter.

Maybe just thinking about the OTC program, could you maybe provide us a little bit of detail and an overview of the data we should expect at the upcoming readout later this quarter? S. S. adolescent and adults, or will we also see a longer-term update from the European patients?

Joe Payne, President and CEO Hi Lily, thanks for the question. Yeah, with dosing completed, you're right. We are preparing for this data disclosure later this quarter. S.

and European data set. The new data, of course, will be the most recent patients that have added and completed dosing here in the United States. But it will also include supplementary data that was requested by the FDA in the Type C meeting earlier this year. And so we just intend to share a fulsome update on the OTC program that includes not only the Phase 2 data, but the requested Type C data and providing additional detail with respect to the regulatory path forward.

I'll leave it at that. With respect to biomarker levels, yes. Well, I know the biomarkers being evaluated and measured are ammonia and glutamine and, of course, urea itself, but maybe, Alan, you can comment or address the rest of the question. Alan H.

Cohen, MD — Chief Medical Officer & Executive Vice President Yeah, great question. I think the two elements that are going to be most important are not just the biomarkers. They're certainly important because it speaks to mode of action, but also how these patients feel as well as function. It'll be the totality of the data that we've been able to generate up to this point, not only relating to safety and tolerability, but also biomarkers, as Joe just mentioned, most notably ammonia levels and glutamine, but also the additional quality of life and functional measures that we're collecting.

So it really will be the totality of all the data is what the agency is interested in wanting to see and which is obviously important to move our program forward. Lily Noso, Analyst at Lyric Partners Thank you. OPERATOR Thank you. We'll take our next question from Pete with Cantor Fitzgerald, please.

Go ahead. Your line is now open. Pete, Analyst at Cantor Fitzgerald Yeah, thank you very much. Hi, Joe and team.

Congrats on the progress. I have a couple of questions on the CF program. First one is how has the cadence of enrollment been, and will you wait for all the patients to complete the study before data disclosure, or is there a possibility of an interim look, and are there plans to adjust the protocol to allow dosing past 12 weeks or three months? Joe Payne, President and CEO Okay, there's a few questions there, but thanks, Pete, for joining the call.

S. sites in Israel and Turkey that are assisting with that challenge. With all rare disease programs, it's all about the cadence of enrollment, and we feel confident. In fact, we've expressed considerable or high level of confidence with respect to the cadence of enrollment rate now that Israel and Turkey are participating in this trial.

With respect to the remainder of the questions, I can turn the time over to Alan. Alan H. Cohen, MD — Chief Medical Officer & Executive Vice President Sure.