Arcturus Therapeutics Announces Second Quarter 2025 Financial Update and Pipeline Progress Cystic fibrosis (ARCT-032) Phase 2 interim data from first nine participants to be presented in September Cystic fibrosis Phase 2

Therapeutics Announces Second Quarter 2025 Financial Update and Pipeline Progress

Cystic fibrosis (ARCT-032) Phase 2 interim data

from first nine participants to be presented in September

Cystic fibrosis Phase 2 trial expected to complete

enrollment by year end 2025

OTC deficiency (ARCT-810) Phase 3 trial design

alignment with regulatory agencies expected H1 2026

Seasonal flu (ARCT-2138) showed positive Phase

BARDA pandemic flu (ARCT-2304) Phase 1 results

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

SAN DIEGO--(BUSINESS WIRE)-Aug 11, 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 second quarter ended June 30, 2025, and provided corporate updates.

"The Company continues to advance and provide

meaningful clinical data across our mRNA therapeutics and vaccines pipeline," said Joseph Payne, President & CEO of Arcturus

Therapeutics. "We are especially pleased with the recent proof-of-concept in our liver platform based on the positive ARCT-810 interim

Phase 2 data and look forward to sharing two cohorts of Phase 2 CF data in September."

Corporate Highlights

Financial Results for the three months ended June 30, 2025

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 six months ended June 30, 2025, was

$28.3 million and $57.7 million, respectively, representing decreases of $21.6 million and $30.2 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 June 30, 2025, were $39.9 million compared with $71.0 million for the three months ended June 30, 2024. Total operating expenses

for the six months ended June 30, 2025, were $86.1 million compared with $139.4 million for the six months ended June 30, 2024.

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 $29.6 million for the three months ended June 30, 2025, compared with $58.7

million for the three months ended June 30, 2024. The decrease was primarily driven by lower manufacturing costs for the KOSTAIVE, LUNAR-FLU,

and cystic fibrosis programs, and reduced clinical trial expenses for KOSTAIVE and Ornithine Transcarbamylase Deficiency. Lower payroll

and employee benefits also contributed to the decrease. These decreases were partially offset by higher clinical costs for cystic fibrosis

following the start of Phase 2 trials in fiscal year 2025.

Research and development expenses were $64.5 million

for the six months ended June 30, 2025, compared with $112.2 million for the three months ended June 30, 2024. The decrease was primarily

driven by lower manufacturing and clinical costs for the KOSTAIVE program, reflecting the program's transition from a development

program to the commercial phase. Additional decreases resulted from lower payroll and benefits expenses and reduced facilities and equipment

costs following the downsizing of operations. These reductions were partially offset by higher clinical expenses for the cystic fibrosis

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 $10.3 million

and $21.7 million for the three and six months ended June 30, 2025, respectively, compared with $12.3 million and $27.2 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 June 30, 2025, Arcturus

reported a net loss of approximately $9.2 million, or ($0.34) per diluted share, compared with a net loss of $17.2 million, or ($0.64)

per diluted share in the three months ended June 30, 2024. For the six months ended June 30, 2025, Arcturus reported a net loss of approximately

$23.3 million, or ($0.86) per diluted share, compared with a net loss of $44.0 million, or ($1.64) per diluted share in the six months

ended June 30, 2024.

Cash Position and Balance Sheet:

Cash, cash equivalents and restricted cash were $253.4

million as of June 30, 2025, and $293.9 million on December 31, 2024. Based on the current pipeline and programs,

the cash runway remains extended into 2028.

Earnings Call: Monday, August 11, 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)

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 of and timing for

providing interim data from the ARCT-032 Phase 2 CF study, the likelihood of and timing for completion of enrollment in the ARCT-032 Phase

2 CF study, the likelihood of and timing for Phase 3 trial design alignment with regulatory agencies for ARCT-810, the timing for Phase

1 results from the BARDA pandemic flu Phase 1 study, the likelihood of and timing for meetings with the FDA and other regulatory agencies

relating to the CF and OTC programs, the likelihood of and timing for initiation of Phase 3 studies for the CF and OTC programs, the timing

for completion of enrollment in the ARCT-032 (CF) Phase 2 study, the likelihood of and timing for approval of the MAA on KOSTAIVE filed

by CSL to the UK MHRA, the likelihood and timing for approvals of NDA applications for KOSTAIVE filed by Meiji Seika Pharma with Japan's

PMDA, the planned U.S. BLA filing and expected approval decision for KOSTAIVE, efforts for optimization and testing for seasonal influenza

program, the timing for Phase 1 results for the pandemic influenza vaccine candidate, the likelihood that general and administrative expenses

will decrease, the likelihood that preclinical or clinical data will be predictive of future clinical results, its current cash position

and expected cash burn and runway, and the impact of general business and economic conditions. Arcturus may not actually achieve the plans,

carry out the intentions or meet the expectations or projections disclosed in any forward-looking statements such as the foregoing and

you should not place undue reliance on such forward-looking statements. These statements are only current predictions or expectations,

and are subject to known and unknown risks, uncertainties, and other factors that may cause our or our industry's actual results,

levels of activity, performance or achievements to be materially different from those anticipated by the forward-looking statements, including

those discussed under the heading "Risk Factors" in Arcturus' most recent Annual Report on Form 10-K, and in subsequent

filings with, or submissions to, the SEC, which are available on the SEC's website at www.sec.gov.

Except as otherwise required by law, Arcturus disclaims any intention or obligation to update or revise any forward-looking statements,

which speak only as of the date they were made, whether as a result of new information, future events or circumstances or otherwise.

ARCTURUS THERAPEUTICS HOLDINGS INC. AND ITS

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