PDE2 Drug Program Builds on FRAXA-Funded Research
Rumi Therapeutics will advance RTX-7340, a potential Fragile X treatment built on research supported by FRAXA. Under an option-to-license agreement with Enthorin Therapeutics, Rumi will take responsibility for developing the candidate, previously known as ENT-7340. Enthorin will provide scientific and technical support during the initial development stages.
FRAXA helped lay the groundwork for this approach by funding Dr. Thomas Maurin’s fellowship with Dr. Barbara Bardoni at INSERM in France. Their studies found increased PDE2A activity in Fragile X mice and showed that inhibiting the enzyme improved brain-cell function and social interactions in animal models. FRAXA supporters helped make this early research possible. In its announcement, Enthorin also credits FRAXA’s support for its efforts to turn these discoveries into potential medicines.
RTX-7340 targets PDE2A, an enzyme that breaks down chemical messengers important for learning and memory. PDE2 is a different target from PDE4D, the member of the PDE4 family targeted by Shionogi’s zatolmilast. Both approaches aim to address signaling disrupted in Fragile X.
Rumi reports that RTX-7340 corrected abnormal brain-wave patterns in Fragile X mice. The company plans to use these findings to help select measurements for future clinical studies, examining whether changes in brain activity are associated with benefits for people with Fragile X.
RTX-7340 is moving toward clinical development. Studies in people will be needed to establish its safety and determine whether it benefits individuals with Fragile X.
Enthorin Therapeutics Announces License Agreement with Rumi Therapeutics for ENT-7340, for Fragile X Syndrome.
Source: Business Wire, October 28, 2026
Rumi to advance ENT-7340 as RTX-7340 for Fragile X syndrome and other neurological disorders
ESCONDIDO, Calif.--(BUSINESS WIRE)--Enthorin Therapeutics, LLC today announced that it has entered into an option-to-license agreement with Rumi Therapeutics for ENT-7340, Enthorin’s IND-enabled phosphodiesterase 2A (PDE2A) inhibitor being developed for Fragile X syndrome (FXS) and other intellectual and developmental disabilities.
Under the agreement, Rumi Therapeutics will assume responsibility for development of ENT-7340, which will be advanced by Rumi under the development name RTX-7340. Enthorin will receive an upfront payment, milestones, and an option exercise fee. As well as be eligible for development, regulatory and commercial milestone payments, and royalties on future net sales. In addition, Enthorin is providing scientific and technical expertise in collaboration with Rumi for the initial stages of the program’s development.
“ENT-7340 represents years of discovery and development work aimed at translating the biology of PDE2 inhibition into effective therapeutics for the treatment of neurodevelopmental disorders such as Fragile X,” said Marco Peters, Ph.D., Co-Founder and Chief Scientific Officer of Enthorin Therapeutics. “Rumi brings distinctive capabilities for evaluating therapeutics in human cellular and organoid models, providing an opportunity to further validate the biology of RTX-7340 in human systems and explore its mechanism of action in Fragile X syndrome and additional indications. We are excited about this agreement and look forward to supporting Rumi during the initial development phase as they advance the program toward clinical development.”
ENT-7340 selectively inhibits PDE2A, an enzyme regulating both cAMP and cGMP signaling pathways involved in neuronal function and synaptic plasticity. The ongoing program will build on Enthorin’s research implicating disrupted cyclic nucleotide signaling and its role in Fragile X syndrome.
Building on FRAXA’s Contributions to Fragile X Therapeutic Development
Enthorin would like to recognize the important contributions of the FRAXA Research Foundation to the development of the PDE2 program. Through sustained support of basic and translational research, FRAXA has helped advance understanding of the molecular consequences of FMRP loss and establish cyclic nucleotide signaling as a promising therapeutic mechanism in Fragile X. FRAXA has supported Enthorin’s efforts to translate these insights into drug-development programs, contributing to the scientific foundation underlying the company’s work in Fragile X syndrome.
“FRAXA has long supported research aimed at understanding how altered cellular signaling contributes to Fragile X syndrome and how those discoveries can be translated into treatments,” said Michael Tranfaglia, M.D., Medical Director and Co-Founder of FRAXA Research Foundation. “Cyclic nucleotide signaling has emerged as an important part of that biology, and we are pleased to have supported Enthorin’s work in this area. The advancement of RTX-7340 toward clinical development is an encouraging next step in translating this science into potential treatments for people with Fragile X.”
About ENT-7340 / RTX-7340
ENT-7340, which will be developed by Rumi Therapeutics as RTX-7340, is an IND-enabled, highly potent and selective small-molecule inhibitor of PDE2A, a phosphodiesterase expressed in brain circuits involved in cognition, sensory processing and behavioral regulation. By inhibiting PDE2A, RTX-7340 modulates intracellular cAMP and cGMP signaling, two cyclic nucleotide pathways with important roles in neuronal function and synaptic plasticity.
In Fragile X mouse models, the compound has demonstrated activity across behavioral and neurophysiological endpoints, including normalization of cognition- and autism-relevant behavioral abnormalities. Together with validated PET target-engagement, these findings provide a translational framework linking drug exposure, PDE2A target engagement and pharmacodynamic effects relevant to Fragile X syndrome.
A Continued Commitment to Fragile X
Enthorin has pursued multiple approaches to restoring cyclic nucleotide signaling and neural plasticity in Fragile X syndrome. The transition of ENT-7340 into Rumi’s development pipeline as RTX-7340 represents another milestone in our mission to translate discoveries in Fragile X biology into potential medicines.
“We are proud to have contributed to this effort and deeply grateful to FRAXA for its support and its longstanding leadership in Fragile X therapeutic development,” Peters said. “Progress in Fragile X has depended on close collaboration among scientists, clinicians, patient organizations and families. Our goal has always been to build on those discoveries and turn strong biological insights into medicines that can make a meaningful difference for patients.”
About Fragile X Syndrome
Fragile X syndrome is a genetic neurodevelopmental disorder caused by changes in the FMR1 gene that reduce or eliminate production of functional FMRP, a protein important for brain development. It is a leading inherited cause of intellectual disability and can affect learning, language, attention, behavior, and social functioning. The condition affects both males and females, with substantial variation in severity.
About Enthorin Therapeutics
Enthorin Therapeutics is a clinical stage pharmaceutical company founded with the goal of developing innovative therapeutics that target brain circuit dysfunction to improve quality of life for patients, families, and communities. The company develops therapies designed to restore neural plasticity and network function in neurological and neurodevelopmental diseases.
Enthorin’s pipeline also includes our PDE4 program, which was licensed to Mirum Pharmaceuticals; ENT-2675 for treatment of Parkinson’s disease MCI and dyskinesia; and a portfolio of GABA alpha 5 negative allosteric modulators for the potential treatment of Dup15q syndrome.
Enthorin leverages translational neurobiology, pharmacology and advanced imaging to bridge pre-clinical and clinical development. Learn more at www.enthorin.com.
About Rumi Therapeutics and Rumi Holdings
Rumi Therapeutics is a drug-development company within Rumi Holdings, the parent company of Rumi Therapeutics and Rumi Scientific. Rumi Therapeutics is advancing RTX-7340 toward clinical evaluation in Fragile X syndrome, drawing on disease-mechanism and translational insights generated through Rumi Scientific’s human organoid platform.
About Rumi Scientific
Rumi Scientific, a company within Rumi Holdings, uses proprietary human organoid technology to identify disease mechanisms and discover potential treatments for neurological, neurodevelopmental, and kidney disorders. Its platform combines genetically defined human disease models with quantitative analysis and scalable screening to support target identification, therapeutic discovery, and translational research.
Contacts
Media / Business Development Contact
Heidi Cervi
Enthorin Therapeutics
hcervi@enthorin.com