Press release·08/07/2026 01:11:22

Financial Performance Overview

Arcturus Therapeutics, a company focused on developing messenger RNA (mRNA) medicines, has reported its financial results for the three and six months ended June 30, 2026. The company has seen a significant decline in revenue compared to the same periods in 2025, primarily due to lower revenue recognized under its collaboration with CSL Seqirus as the KOSTAIVE vaccine transitions from development to the commercial phase.

At the same time, Arcturus has been able to reduce its operating expenses, particularly in research and development, leading to a smaller net loss for the first half of 2026 compared to the prior year. The company’s key pipeline programs, including LUNAR-CF and LUNAR-OTC, continue to progress, with the LUNAR-CF program advancing into a new cohort of a Phase 2 clinical trial.

Revenue Trends

Arcturus reported total revenue of $2.9 million for the three months ended June 30, 2026, down 90% from $28.3 million in the same period of 2025. For the six-month period, revenue declined 91% to $5.0 million, down from $57.7 million in the first half of 2025.

The significant drop in revenue was primarily driven by lower collaboration revenue, which decreased by 96% and 97% for the three and six-month periods, respectively. This was due to reduced revenue recognized under Arcturus’ collaboration with CSL Seqirus as the KOSTAIVE vaccine transitioned from the development to the commercial phase.

Grant revenue also declined, falling 45% and 54% for the three and six-month periods, respectively, mainly related to reduced funding from the Biomedical Advanced Research and Development Authority (BARDA), partially offset by increased grant revenue from the Gates Foundation.

Expense Management

Arcturus was able to significantly reduce its operating expenses in the first half of 2026 compared to the prior year period. Total operating expenses were $28.5 million for the three months ended June 30, 2026, down 29% from $39.9 million in the same period of 2025. For the six-month period, operating expenses decreased 31% to $59.5 million, down from $86.1 million in the first half of 2025.

The primary driver of the expense reduction was in research and development (R&D), which declined 41% and 39% for the three and six-month periods, respectively. This was due to lower clinical trial expenses associated with the BARDA, LUNAR-CF, and LUNAR-OTC programs, as well as reduced manufacturing costs related to the LUNAR-COVID and LUNAR-OTC programs. Arcturus also saw decreases in payroll and benefits costs, including lower share-based compensation expense and a reduction in headcount.

General and administrative (G&A) expenses remained relatively flat, increasing slightly by 6% for the three-month period but decreasing 6% for the six-month period. The slight increase in the three-month period was related to higher legal and professional fees, offset by reduced share-based compensation. The decrease in the six-month period was primarily due to lower share-based compensation expense, reduced payroll and benefits costs resulting from lower headcount, and lower facilities costs.

Pipeline Progress

Arcturus’ key pipeline programs continue to advance:

• LUNAR-CF (ARCT-032): This mRNA therapeutic candidate for cystic fibrosis is progressing in a Phase 2 clinical trial. The ongoing study is evaluating the safety and efficacy of ARCT-032 in CF adults who do not benefit from current CFTR modulators. The treatment has been generally safe and well-tolerated, and a fourth cohort of up to 20 subjects has begun enrolling to assess longer-term safety, tolerability, and early evidence of clinical efficacy.

• LUNAR-OTC (ARCT-810): The LUNAR-OTC program, which addresses ornithine transcarbamylase (OTC) deficiency, has completed enrollment in an open-label Phase 2 study evaluating safety and pharmacodynamics in adult and adolescent patients. Arcturus continues to evaluate supplementary data to inform regulatory discussions and preparation for an End-of-Phase 2 meeting.

In addition to its internal pipeline, Arcturus has entered into a strategic collaboration with Thermo Fisher Scientific to provide contract development and manufacturing organization (CDMO) and contract research organization (CRO) services for the ARCT-032 program. This agreement includes up to $40 million in clinical manufacturing services from Thermo Fisher and up to $40 million in CRO services from Thermo Fisher’s affiliate, PPD.

Termination of Vaccine Collaboration with CSL Seqirus

Arcturus has also announced the termination of its vaccine collaboration with CSL Seqirus. Under the termination agreement, Arcturus received a one-time cash payment of $12 million and was released from a liability and an R&D credit worth approximately $16 million.

As a result of the termination, Arcturus has regained strategic control of its vaccine portfolio, including the KOSTAIVE vaccine and its programs for seasonal influenza, pandemic influenza, respiratory syncytial virus (RSV), and Epstein-Barr virus (EBV). The company will continue to work with Meiji Seika Pharma in Japan for the Northern Hemisphere 2026-2027 season, after which it expects to work directly with Meiji for KOSTAIVE activities in Japan.

Arcturus is obligated to pay CSL Seqirus single-digit royalties and revenue-sharing payments on future commercialization of vaccine products formerly licensed under the collaboration agreement, where certain CSL Seqirus intellectual property is incorporated. The company also expects to recognize approximately $5.2 million in deferred revenue from CSL Seqirus during the third quarter of 2026.

Outlook and Analysis

Arcturus’ financial performance in the first half of 2026 reflects the company’s transition from the development to the commercial phase of its KOSTAIVE vaccine, as well as its continued progress in advancing its internal pipeline of mRNA therapeutic candidates.

The significant decline in revenue, particularly collaboration revenue, is a result of this transition, as Arcturus recognizes less revenue from its partnership with CSL Seqirus. However, the company has been able to effectively manage its operating expenses, particularly in R&D, leading to a smaller net loss compared to the prior year period.

Arcturus’ key pipeline programs, LUNAR-CF and LUNAR-OTC, continue to advance, with the LUNAR-CF program moving into a new cohort of a Phase 2 trial. The strategic collaboration with Thermo Fisher also provides additional support for the LUNAR-CF program, with up to $80 million in combined CDMO and CRO services.

The termination of the vaccine collaboration with CSL Seqirus is a significant event, as it allows Arcturus to regain control of its broader vaccine portfolio, including KOSTAIVE. This provides the company with more flexibility and strategic options for these programs going forward, although it also comes with certain ongoing financial obligations to CSL Seqirus.

Overall, Arcturus appears to be navigating the transition from a predominantly development-stage company to one with both development and commercial-stage programs. The company’s ability to effectively manage its expenses while advancing its pipeline is a positive sign, and the termination of the CSL Seqirus collaboration could open up new opportunities for the company’s vaccine portfolio. However, the significant decline in revenue, particularly from the KOSTAIVE collaboration, remains a challenge that Arcturus will need to address in the coming quarters and years.

Table 1: Revenue Summary

(in thousands)	Three Months Ended June 30		Six Months Ended June 30
	2026	2025	Change	2026
Collaboration revenue	$880	$24,510	-96%	$1,490
Grant revenue	$2,079	$3,791	-45%	$3,530
Total	$2,959	$28,301	-90%	$5,020

Table 2: Operating Expenses

(in thousands)	Three Months Ended June 30		Six Months Ended June 30
	2026	2025	Change	2026
Research and development, net	$17,515	$29,579	-41%	$39,042
General and administrative	$10,989	$10,338	6%	$20,454
Total	$28,504	$39,917	-29%	$59,496