First-in-Class Disease-Modifying Therapeutics in Rare Cardiac and Skeletal Muscle Diseases

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ARMGO Pharma Publishes Positive Phase 1b Trial Results of Rycal® ARM210 for the Treatment of Ryanodine Receptor 1 Related Myopathies

Pioneering world class science to treat ryanodine receptor (RyR)-related diseases

ARMGO Pharma is a privately owned, venture-backed, biotech company that is developing small molecule drugs that repair leaky Ryanodine Receptor (RyR) calcium channels associated with human diseases. We hold an exclusive, worldwide license from Columbia University for its RyR technology and know-how.

Our primary focus is on two orphan diseases: the life-threatening cardiac disease Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), and the severe muscle disease RYR1-Related Myopathy (RYR1-RM). The two conditions occur due to genetic mutations in the RYR genes. Mutations in RYR2 can lead to cardiac arrhythmias and sudden cardiac death, while mutations in RYR1 can cause muscle weakness.

ARMGO’s molecules, termed Rycals® are designed to repair leaky RyR channels. Since the cause of the symptoms of CPVT and RYR1-RM is an abnormal calcium leak due to these mutations, Rycals® hold the promise of disease-modifying therapy for these two orphan genetic diseases. Beyond these genetic conditions Rycals® have therapeutic potential for other disorders associated with leaky RyRs.

The ARMGO Team

Eugene Marcantonio, <br/>MD, PhD
Eugene Marcantonio,
Chief Executive Officer
Yael Webb, <br/>PhD, JD
Yael Webb,
Chief Operating Officer/General Counsel
Kathi Larson, <br/>BBA
Kathi Larson,
Chief Financial Officer
Sandro Belvedere, <br/>PhD
Sandro Belvedere,
Senior Vice President, Research
Rachael Russell
Rachael Russell
Vice President Clinical Operations
Yigal Pinto, <br/>MD, PhD
Yigal Pinto,
Medical Director
Hermann-Josef Kaiser, <br/>PhD
Hermann-Josef Kaiser,
Vice President Business Development
John Ford, <br/>PhD
John Ford,
Executive Chairman
Andrew Marks, <br/>MD
Andrew Marks,
Eugene Marcantonio, <br/>MD, PhD
Eugene Marcantonio,
Chief Executive Officer
Peter Neubeck, <br/>MD
Peter Neubeck,
Investor Director
Geert-Jan Mulder, <br/>MD
Geert-Jan Mulder,
Investor Director
Tomer Kariv, <br/>JD
Tomer Kariv,
Investor Director
Dmitrij Hristodorov, <br/>PhD
Dmitrij Hristodorov,
Investor Director
Andrew Schiff, <br/>MD
Andrew Schiff,
Board Observer
Antoine Boulanger, <br/>PhD
Antoine Boulanger,
Board Observer


RyRs are homotetrameric intracellular calcium release channels responsible for Ca2+ flow from the sarcoplasmic/endoplasmic reticula (SR/ER) into the cytoplasm of most cell types. RyR1 is the predominant isoform in mammalian skeletal muscle, where SR Ca2+ release via RyR1 is required for excitation-contraction coupling and normal muscle function. RyR2 is the predominant isoform in cardiac muscle where ER Ca2+ release via RyR2 is required for normal cardiac muscle function. Human genetic mutations in RYR1 and RYR2 genes cause calcium to leak from RyR channels, leading to disease (Figure 1).

RyR channels normally alternate between a resting (closed) and excited (open) state. In certain diseases, RyR is modified and becomes leaky. Inhibition of the channel would stop the leak, but this intervention would not generally be beneficial since it would block the normal function of RyR. Rycals®, molecules that can restore normal channel function without blocking RyR, open the possibility of therapeutic interventions.

RyR1 and Skeletal Muscle

RyR1 plays a critical role in skeletal muscle, and RyR1 mutations in humans lead to a progressive myopathy, known as RYR1-RM. The causative mutations lead to a leaky channel, robbing the muscle of the ability to respond effectively to contraction signals, leading to muscle weakness.

RyR2 and Exercise-induced Sudden Cardiac Death

CPVT is characterized by exercise-induced fatal cardiac arrhythmias due to RyR2 mutations that render the channel leaky. Under normal states, the channel opening occurs during the contractile phase of the cardiac cycle, namely during systole. CPVT mutations render the channels leaky such that opening can occur inappropriately with exercise or stress leading to often fatal arrhythmias (Figure 2).

Figure 1: Model of RyR function. RyR controls the flow of calcium (Ca2+) from inside the sarcoplasmic reticulum (SR) through the membrane to the cytoplasm. (Left) Normal RyR regulates calcium flow by alternating between a closed and open state. (Middle) In CPVT and RYR1-RM, mutated RyR is leaky, leading to abnormal calcium flow, resulting in disease symptoms. Post-translational modifications of RyR further exacerbate the leak. In other muscle disorders such as DMD, heart failure or sarcopenia, post-translational modifications of RyR can make the channel leaky, leading to abnormal calcium flow, resulting in disease symptoms. (Right) Rycals® bind to leaky channels and repair the leak regardless of the cause of the leak, restoring normal channel function. Rycals® do not block RyR.

ARMGO has progressed Rycal® ARM210 into clinical development, with the goal of repairing leaky RyR channels in human diseases. Our focus is on the two human diseases with genetic mutations in RYRs, which validate RyR as a therapeutic target. The two diseases are the severe muscle disease RYR1-Related Myopathy (RYR1-RM) with mutations in RYR1, and the life-threatening cardiac disease Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), with mutations in RYR2 in most cases. In vitro, as well as in animal studies, ARM210 has been shown to be disease-modifying, by repairing the leaky channels and improving disease symptoms.

The mechanism by which ARM210 is believed to repair leaky channels has been elucidated by ARMGO’S founder, Dr. Andrew Marks (Columbia University). First, Melville et al., (2022) identified the binding site and mechanism of action of ARM210 on RyR1. A second study (Miotto et al., 2022) has recently delineated the structural basis for CPVT mutations in RyR2 and the mechanism of action of ARM210 on those mutant forms.

Using a series of cryo-electron microscopy structures, Miotto et al., showed that RyR2-R2474S, a mutant channel harboring a point mutation causing CPVT in humans, already adopts a primed state whereas wild-type RyR2 did not (Figure 2). The primed state has been shown to be a transition between the closed and open conformations of these channels. Once primed, the mutant channel can be more easily shifted to the open conformation. The normal channel will be open only during systole, which is the appropriate phase of the cardiac cycle for calcium release. The mutant channel however can be open in both systole and diastole with exercise and/or stress. This can lead to the ventricular arrhythmias characteristic of CPVT (Figure 2).

ARM210 was shown to bind and reverse the primed state of mutant RyR2. This binding stabilized the closed state and prevented pathological pore opening.

Clinical Studies

ARM210 is currently being investigated in both RYR1-RM and CPVT patients, to demonstrate proof-of-concept in both diseases.

Figure 2: In normal tissue, RyRs are in a closed resting state, with low open probability. Stress conditions lead to phosphorylation resulting in a “primed state”, an intermediate between closed and open state. Stimuli such as calcium shift the primed state to an opened state. For CPVT variants (shown with cyan stars), the resting state is already in a “primed” state. This correlates with the higher open probability during exercise, which results in arrhythmias (due to inappropriate opening in diastole), and sudden cardiac death. This pathological state can be reversed by treatment with Rycals® (shown as purple hexagon) to restore normal channel function. Scheme adopted from Miotto et al, 2022

Rycal S48168 (ARM210) for RYR1-related myopathies: a phase one, open-label, dose-escalation trial

Todd, Lawal, Chrismer, Kokkinis, Grunseich, Jain, Waite, Biancavilla, Pocock, Brooks, Mendoza, Norato, Cheung, Riekhof, Varma, Colina-Prisco, Emile-Backer, Meilleur, Marks, Webb, Marcantonio, Foley, Bönnemann, Mohassel. Eclinicalmedicine. 2024.

Targeting ryanodine receptors to treat human diseases

Andrew R Marks. J Clin Invest. 2023 PMID: 36647824

Structural analyses of human ryanodine receptor type 2 channels reveal the mechanisms for sudden cardiac death and treatment

Miotto, Weninger, Dridi, Yuan, Liu, Wronska, Melville, Sittenfeld, Reiken, Marks. Sci Adv. 2022. PMID: 35857850

A drug and ATP binding site in type 1 ryanodine receptor

Melville, Dridi, Yuan, Reiken, Wronska, Liu, Clarke, Marks. Structure. 2022. PMID: 35580609

Intracellular calcium leak as a therapeutic target for RYR1-related myopathies

Kushnir, Todd, Witherspoon, Yuan, Reiken, Lin, Munce, Wajsberg, Melville, Clarke, Wedderburn-Pugh, Wronska, Razaqyar, Chrismer, Shelton, Mankodi, Grunseich, Tarnopolsky, Tanji, Hirano, Riazi, Kraeva, Voermans, Gruber, Allen, Meilleur, Marks. Acta Neuropathol. 2020. PMID: 32236737

Ryanodine channel complex stabilizer compound S48168/ARM210 as a disease modifier in dystrophin-deficient mdx mice: proof-of-concept study and independent validation of efficacy

Capogrosso, Mantuano, Uaesoontrachoon, Cozzoli, Guistino, Dow, Srinivassane, Filipovic, Bell, Vandermeulen, Massari, De Bellis, Conte, Pierno, Camerino, Liantonio, Nagaraju, De Luca. FASEB J. 2018. PMID: 29097503


ARMGO Pipeline

Clinical Trials

ARMGO is committed to bringing first-in-class and best-in-class therapeutics to patients with cardiac and skeletal muscle disorders. We are developing a novel class of compounds, Rycals®, which target and fix leaky Ryanodine Receptor (RyR) channels that cause human diseases.

Our clinical lead, ARM210 is currently being investigated in two RyR genetic disorders:

1. Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) – a rare condition causing life threatening changes in heart rhythm Identifier: NCT05122975


2. Ryanodine receptor 1-Related Myopathy (RYR1-RM) – a rare condition causing significant muscle weakness in adults and children. Identifier: NCT04141670

To follow our progress and news announcements please follow ARMGO Pharma Inc. on LinkedIn.


ARMGO Pharma is at the forefront of science and innovation, dedicated to developing a groundbreaking new class of drugs – Rycals® – for muscle and heart diseases. Here, you’ll find yourself part of a global, vibrant team, where each day brings new challenges and opportunities. We have fostered a collaborative culture which enables creativity and excellence and allows each team member to flourish.

The professional and personal growth of our employees is very important to us, and we are committed to helping you thrive and reach your full potential. Join us and together we can achieve our mission to transform the landscape of healthcare and offer new hope to patients worldwide suffering from muscle and heart disease.

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News & Events

Join ARMGO at the World Orphan Drug Congress USA, Boston, USA, April 23 – 25, 2024
ARMGO Pharma Publishes Positive Phase 1b Trial Results of Rycal® ARM210 for the Treatment of Ryanodine Receptor 1 Related Myopathies
ARMGO Pharma Enrolls First Patient in Phase 2 Trial of ARM210 for the Treatment of Catecholaminergic Polymorphic Ventricular Tachycardia


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