Arcturus Therapeutics Announces Third Quarter 2025 Financial Update and Pipeline Progress Encouraging CF interim Phase 2 data support continued and expanded trial design 12-week safety and preliminary efficacy study in u

Therapeutics Announces Third Quarter 2025 Financial Update and Pipeline Progress

Encouraging CF interim Phase 2 data support

continued and expanded trial design

12-week safety and preliminary efficacy study

in up to 20 CF participants planned to start H1 2026

Additional cost reductions planned in fourth

quarter to extend cash runway

Investor conference call at 4:30 p.m. ET today

SAN DIEGO--(BUSINESS WIRE)-Nov 10, 2025-- Arcturus

Therapeutics Holdings Inc. (the "Company", "Arcturus", Nasdaq: ARCT), a commercial messenger RNA medicines

company focused on the development of liver and respiratory rare disease therapeutics and infectious disease vaccines, today announced

its financial results for the third quarter ended September 30, 2025, and provided corporate updates.

"We were pleased to share the initial findings

of ARCT-032 clinical activity with the CF community last month at the NACFC," said Joseph Payne, President & CEO of Arcturus

Therapeutics. "Conversations at NACFC with CF patients, physicians, investigators and global experts reinforced our commitment to

advance ARCT-032 further into development. We look forward to initiating a 12-week safety and preliminary efficacy study in first half

of 2026. Our team is also working diligently to achieve alignment with regulatory agencies regarding pivotal studies of ARCT-810 in adults

and young children with OTC deficiency."

"The observed mucus plug reduction after

28 days of treatment with ARCT-032 in people with Class I CF is encouraging," said Denis Hadjiliadis, MD, MMHS, FRCP(C), Professor

and Cystic Fibrosis Program Director, Perelman School of Medicine, University of Pennsylvania. "Clearance of mucus suggests that

treatment with ARCT-032 is acting on the thick mucus defect which is fundamental in CF; more extended treatment with ARCT-032 could provide

further reduction in mucus burden leading to more meaningful benefits, including lung function and structural lung defect improvement. These

changes could ultimately lead to reduction in exacerbations and change the clinical course of this progressive disease."

"The sudden changes in regulatory requirements

by the FDA for COVID-19 vaccines have delayed the U.S. BLA filing for KOSTAIVE indefinitely. We have decided to reduce additional

expenses to extend the runway for the CF and OTC deficiency programs," said Andy Sassine, CFO of Arcturus Therapeutics. "We

anticipate continued support from CSL to commercialize KOSTAIVE in Asia and Europe and will provide more details on our year end call."

Corporate Highlights

Financial Results for the three months ended September 30,

Revenues in conjunction with strategic alliances

Arcturus' primary revenue streams include

license fees, consulting and related technology transfer fees, reservation fees and collaborative payments received from research and

development arrangements with pharmaceutical and biotechnology partners. Revenue for the three and nine months ended September 30, 2025,

was $17.2 million and $74.8 million, respectively, representing decreases of $24.5 million and $54.7 million compared to the same periods

in 2024. These declines were primarily driven by reduced revenue from the CSL collaboration, reflecting lower supply agreement activity

and lower amortization of the upfront payment as KOSTAIVE progresses toward commercialization.

Total operating expenses for the three months

ended September 30, 2025, were $33.7 million compared with $52.4 million for the three months ended September 30, 2024. Total operating

expenses for the nine months ended September 30, 2025, were $119.8 million compared with $191.8 million for the nine months ended September

Research and development expenses:

Research and development expenses consist primarily

of external manufacturing costs, in vivo research studies and clinical trials performed by contract research organizations, clinical and

regulatory consultants, personnel-related expenses, facility-related expenses and laboratory supplies related to conducting research and

development activities. Research and development expenses were $23.3 million for the three months ended September 30, 2025, compared with

$39.1 million for the three months ended September 30, 2024. The decrease was primarily driven by lower manufacturing costs for the LUNAR-COVID,

LUNAR-FLU, and LUNAR-CF programs, as well as reduced clinical trial expenses for LUNAR-COVID and LUNAR-CF. Lower payroll and employee

benefits further contributed to the decrease.

Research and development expenses were $87.7 million

for the nine months ended September 30, 2025, compared with $151.4 million for the nine months ended September 30, 2024. The decrease

was primarily driven by lower manufacturing and clinical costs related to the LUNAR-COVID program, reflecting the program's transition

from a development program to the commercial phase. Additional decreases were attributable to lower manufacturing costs for the LUNAR-CF

and LUNAR-FLU programs. These reductions were partially offset by higher clinical costs for Phase 2 of the LUNAR-CF program. Payroll and

benefits expenses also decreased, primarily due to lower stock-based compensation expense.

General and Administrative Expenses:

General and administrative expenses primarily

consist of salaries and related benefits for executive, administrative, legal and accounting functions and professional service fees for

legal and accounting services as well as other general and administrative expenses. General and administrative expenses were $10.4 million

and $32.1 million for the three and nine months ended September 30, 2025, respectively, compared with $13.3 million and $40.4 million

in the comparable periods last year. The decreases in both periods were primarily due to reduced share-based compensation expense as well

as reduced payroll and benefits. We expect general and administrative expenses to continue to decrease slightly during the next twelve

months driven by lower share-based compensation costs.

For the three months ended September 30, 2025,

Arcturus reported a net loss of approximately $13.5 million, or ($0.49) per diluted share, compared with a net loss of $6.9 million, or

($0.26) per diluted share in the three months ended September 30, 2024. For the nine months ended September 30, 2025, Arcturus reported

a net loss of approximately $36.7 million, or ($1.35) per diluted share, compared with a net loss of $50.9 million, or ($1.89) per diluted

share in the nine months ended September 30, 2024.

Cash Position and Balance Sheet:

Cash, cash equivalents

and restricted cash were $237.3 million as of September 30, 2025, compared to $293.9million on December 31, 2024. Based on the additional

planned cost reduction in Q4 2025 and the delay in Phase 3 CF clinical trial commencement until 2027, the cash runway remains extended

Earnings Call: Monday, November 10, 2025 @ 4:30 p.m. ET

Founded in 2013 and based in San Diego, California, Arcturus

Therapeutics Holdings Inc. (Nasdaq: ARCT) is a commercial mRNA medicines and vaccines company with enabling technologies: (i) LUNAR

lipid-mediated delivery, (ii) STARR mRNA technology (sa-mRNA) and (iii) mRNA drug substance along with drug product manufacturing

expertise. Arcturus developed KOSTAIVE , the first self-amplifying messenger RNA (sa-mRNA) COVID vaccine in the world to be approved.

Arcturus has an ongoing global collaboration for innovative mRNA vaccines with CSL Seqirus, and a joint venture in Japan, ARCALIS,

focused on the manufacture of mRNA vaccines and therapeutics. Arcturus' pipeline includes RNA therapeutic candidates to potentially

treat OTC deficiency and cystic fibrosis (CF), along with its partnered mRNA vaccine programs for SARS-CoV-2 (COVID-19) and influenza.

Arcturus' versatile RNA therapeutics platforms can be applied toward multiple types of nucleic acid medicines including messenger

RNA, small interfering RNA, circular RNA, antisense RNA, self-amplifying RNA, DNA, and gene editing therapeutics. Arcturus' technologies

are covered by its extensive patent portfolio (over 500 patents and patent applications in the U.S., Europe, Japan, China,

and other countries). For more information, visit www.ArcturusRx.com. In addition, please connect with us on X (formerly

Twitter) and LinkedIn.

Forward Looking Statements

This press release contains forward-looking statements

that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform

Act of 1995. Any statements, other than statements of historical fact included in this press release, are forward-looking statements,

including those regarding strategy, future operations, the likelihood of success of the Company's pipeline (including ARCT-032 and

ARCT-810) and partnered programs (including the COVID-19 and flu programs partnered with CSL Seqirus), the likelihood that clinical data,

including interim data, will be predictive of future clinical results, the likelihood that observed mucus plug reduction is predictive

of future and future reduction and will lead to lung function or structural lung defect improvements, the plans to enroll subjects in

the third cohort of the Phase 2 clinical trial of ARCT-032, the likelihood and timing for initiation, and size and scope, of a planned

12-week safety and preliminary efficacy study for ARCT-032, plans to advance ARCT-032 further into development, the likelihood and timing

for achieving alignment with regulatory agencies on pivotal studies for ARCT-810, the likelihood of success of any collaboration including

the anticipated continued support from CSL to commercialize KOSTAIVE, the continued determination that ARCT-032 is generally safe and

well tolerated, the likelihood of further development of a self-amplifying mRNA pandemic influenza vaccine candidate, the likelihood that

preclinical or clinical data will be predictive of future clinical results, the likelihood that general and administrative expenses will