Arcturus Therapeutics Holdings Inc. is an American RNA medicines

biotechnology company Biotechnology is a multidisciplinary field that involves the integration of natural sciences and engineering sciences in order to achieve the application of organisms and parts thereof for products and services. Specialists in the field are kn ...

focused on the discovery, development and commercialization of therapeutics for

rare disease A rare disease is any disease that affects a small percentage of the population. In some parts of the world, the term orphan disease describes a rare disease whose rarity results in little or no funding or research for treatments, without financi ...

s and infectious diseases. Arcturus has developed proprietary

lipid nanoparticle Lipid-based nanoparticles are very small spherical particles composed of lipids. They are a novel pharmaceutical drug delivery system (part of nanoparticle drug delivery), and a novel pharmaceutical formulation. There are many subclasses of ...

RNA therapeutics RNA therapeutics are a new class of medications based on RNA, ribonucleic acid (RNA). Research has been working on clinical use since the 1990s, with significant success in cancer therapy in the early 2010s. In 2020 and 2021, mRNA vaccines have b ...

for nucleic acid medicines including

small interfering RNA Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA, double-stranded non-coding RNA, non-coding RNA, RNA molecules, typically 20–24 base pairs in length, similar to microR ...

(siRNA), messenger RNA (mRNA), gene editing RNA, DNA, antisense oligonucleotides, and

microRNA Micro ribonucleic acid (microRNA, miRNA, μRNA) are small, single-stranded, non-coding RNA molecules containing 21–23 nucleotides. Found in plants, animals, and even some viruses, miRNAs are involved in RNA silencing and post-transcr ...

. The company develops RNA therapeutics for the treatment of rare diseases such as

ornithine transcarbamylase deficiency Ornithine transcarbamylase deficiency also known as OTC deficiency is the most common urea cycle disorder in humans. Ornithine transcarbamylase, the defective enzyme in this disorder, is the final enzyme in the proximal portion of the urea cycle, r ...

, and respiratory diseases such as

cystic fibrosis Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that impairs the normal clearance of Sputum, mucus from the lungs, which facilitates the colonization and infection of the lungs by bacteria, notably ''Staphy ...

. Vaccine medicines include a vaccine candidate for COVID-19 and an influenza vaccine in the

preclinical development In drug development, preclinical development (also termed preclinical studies or nonclinical studies) is a stage of research that begins before clinical trials (testing in humans) and during which important feasibility, iterative testing and dr ...

phase. The vaccine for COVID-19 was authorised in Japan in 2023 and the European Union in 2025.

History

Founded in 2013 by Joseph Payne and Pad Chivukula, Arcturus Therapeutics is headquartered in San Diego, California, USA. Initially, they developed a proprietary

delivery system called Lunar, able to safely deliver therapeutic RNA or DNA to target cells inside a patient's body. In September 2017, Arcturus Therapeutics merged with Alcobra Ltd., an Israeli pharmaceutical company. In February of 2018, Joseph Payne was dismissed as president and CEO by the Arcturus Therapeutics board of directors at that time. In the aftermath, as the largest shareholder, Joseph Payne filed formal requests to hold a meeting of shareholders for the purpose of selecting new members to the Arcturus Therapeutics board of directors. Under applicable law, Arcturus’ board must have honored Payne’s request by establishing a meeting date and convening said meeting within a clearly defined timeframe. Rather than adhering to the law, the Board ignored the applicable deadlines and opted to postpone the shareholder meeting indefinitely. Joseph Payne subsequently filed legal proceedings with the Israeli Court which ruled in favor of upholding shareholder rights by sanctioning the meeting of shareholders. In April of 2018, the Arcturus Therapeutics board of directors at the time filed their own complaint against Joseph Payne and his nominees to the board. In May of 2018, a legal settlement was agreed upon: 4 new directors were appointed to the board (Peter Farrell, Andrew Sassine, James Barlow and Magda Marquet) resulting in the resignation of Stuart Collinson, Daniel Geffken, David Shapiro, and Craig Willett. Other key terms of the settlement agreement included mutual releases of all parties and the agreement by Arcturus Therapeutics and Joseph Payne to terminate all pending litigation.

Products

Lunar

Lunar is a

drug delivery system which targets specific cells inside the body to deliver a payload of RNA into the cell. Once release of the RNA into the cell occurs, the normal translational machinery of the cell can interact with the RNA to make a functional protein with a therapeutic effect. Prior to the Lunar technique, efficient

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, an ...

delivery has also been challenging because existing lipid

nanoparticle A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At ...

s at the time could cause liver damage and elicit a strong

immune response An immune response is a physiological reaction which occurs within an organism in the context of inflammation for the purpose of defending against exogenous factors. These include a wide variety of different toxins, viruses, intra- and extracellula ...

. This lipid nanoparticle delivery system has been used to deliver

ornithine transcarbamylase Ornithine transcarbamylase (OTC) (also called ornithine carbamoyltransferase) is an enzyme () that catalyzes the reaction between carbamoyl phosphate (CP) and ornithine (Orn) to form citrulline (Cit) and phosphate (Pi). There are two classes of O ...

messenger RNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the ...

to liver cells in order to treat citrin deficiency and

. OTCD is the most common

urea cycle disorder The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic. The urea cycle converts highly ...

, which impacts an individual's ability to remove toxic waste products from the body. In collaboration with the

Salk Institute for Biological Studies The Salk Institute for Biological Studies is a scientific research institute in the La Jolla community of San Diego, California. The independent, non-profit institute was founded in 1960 by Jonas Salk, the developer of the polio vaccine; among th ...

in La Jolla, California, successful delivery of a Factor IX messenger RNA to the liver was reported, which suggested viability of the approach to potentially treat diseases requiring protein replacement. Researchers at the

MD Anderson Cancer Center The University of Texas MD Anderson Cancer Center (colloquially MD Anderson Cancer Center) is a comprehensive cancer center and autonomous university of the University of Texas System in Houston, Texas. It is the largest cancer center in the wo ...

also showed the application of mRNA delivered in nanoparticles using the Lunar platform for the treatment of

malignancy Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

in intracerebral

glioma A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain and central nervous system tumors and 80% of ...

. In 2019, a drug named ARCT-810 which uses Lunar, received FDA

orphan drug An orphan drug is a medication, pharmaceutical agent that is developed to treat certain rare medical conditions. An orphan drug would not be profitable to produce without government assistance, due to the small population of patients affected by th ...

status for treating ornithine transcarbamylase deficiency. The orphan drug designation is granted to drugs capable of treating rare diseases that affect less than 200,000 people in the United States, and grants seven years of marketing exclusivity after approval. On April 13, 2020, it was announced that the company's

investigational new drug The United States Food and Drug Administration's Investigational New Drug (IND) program is the means by which a pharmaceutical industry, pharmaceutical company obtains permission to start human clinical trials and to ship an experimental drug inte ...

application for Phase 1b study in patients with OTCD was allowed to proceed by the U.S. FDA. Clinical trials in patients began in June 2020.

Lunar-COV19

ARCT-021 and Starr

In response to the

COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...

, Arcturus partnered with

Duke–NUS Medical School The Duke–NUS Medical School (Duke–NUS) is a graduate medical school in Singapore. Established in April 2005 as the Duke–NUS Graduate Medical School, it is Singapore's second medical school (after the NUS Yong Loo Lin School of Medicine and ...

to develop a

COVID-19 vaccine A COVID19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 ( COVID19). Knowledge about the structure and fun ...

using a combination of self-replicating mRNA with a Lunar delivery platform which increases the level and duration of expression of a therapeutic protein). The company also partnered with Catalent and Recipharm, contract development and manufacturing organizations, to manufacture multiple batches of Arcturus'

COVID-19 Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic. The symptoms of COVID‑19 can vary but often include fever ...

mRNA vaccine An mRNA vaccine is a type of vaccine that uses a copy of a molecule called messenger RNA (mRNA) to produce an immune response. The vaccine delivers molecules of antigen-encoding mRNA into cells, which use the designed mRNA as a blueprint to b ...

candidate. Lunar-COV19 clinical trials in healthy volunteers began in July 2020. Phase 2 clinical trials were approved in the United States and Singapore by the FDA and HSA, respectively in December 2020.

Next-generations

On 2 August 2021, ARCT-154 started a clinical trial in Vietnam for next-generation development. The next day, the firm announced that the application of approval for the clinical trial Phase I/II in Singapore called ARCT-165. Also application of ARCT-154 for phase I/II. The vaccine was authorised in Japan in November 2023, and the European Union in February 2025. Other projects Lunar-CF is a project in collaboration with the

Cystic Fibrosis Foundation The Cystic Fibrosis Foundation (CFF) is a 501(c)(3) non-profit organization in the United States established to provide the means to cure cystic fibrosis (CF) and ensure that those living with CF live long and productive lives. The Foundation pro ...

to treat

. Lunar-FLU is a wholly owned program to protect against the

influenza Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These sympto ...

virus. Arcturus is combining its self-replicating mRNA Starr technology with Lunar to develop a prophylactic vaccine against influenza. Lunar-GSD is a project in collaboration with

Ultragenyx Ultragenyx Pharmaceutical Inc. is an American biopharmaceutical company involved in the research and development of novel products for treatment of rare and ultra-rare genetic diseases for which there are typically no approved treatments and hig ...

to treat glycogen storage disease type III. Lunar-Rare is a project in collaboration with

to develop therapeutic candidates for rare disease targets. Lunar-HBV is a project in collaboration with Janssen to develop medicines for the treatment of hepatitis B virus infection. Lunar-NASH is a project in collaboration with

Takeda is a Japanese name, Japanese family name.1990 Census Name Files