RespireRx Pharmaceuticals Inc. Announces Discovery of a New GABAkine Neuromodulator that Protects Against Seizures and Lethality


Glen Rock, N.J., March 16, 2022 (GLOBE NEWSWIRE) -- RespireRx Pharmaceuticals Inc. (OTCQ:RSPI) (“RespireRx” or the “Company”), a leader in the discovery and development of innovative and revolutionary treatments to combat diseases caused by disruption of neuronal signaling, is pleased to announce that scientists associated with the Company have published a manuscript detailing the pharmacology of its newest asset, D5-KRM-II-81. The paper titled Metabolism, pharmacokinetics, and anticonvulsant activity of a deuterated analog of the α2/3-selective GABAkine KRM-II-81 in Biopharmaceutics and Drug Disposition. 2022 Feb 22. doi: 10.1002/bdd.2313. Epub ahead of print. PMID: 35194800.

The multidisciplinary team of authors was led by Dr. Jeffrey M. Witkin, a senior research fellow at RespireRx with contributions from academic collaborators at the University of Wisconsin-Milwaukee, Ascension St. Vincent and Indiana University/Purdue University, and the University of Belgrade in Serbia. Authors also include Arnold Lippa, RespireRx Executive Chairman, Interim President and Interim Chief Executive Officer and Chief Scientific Officer. Dr. Lippa is a pioneer in this field since its inception being the first to identify compounds with anxiolytic effects without sedation and to bring them into clinical development (e.g., ocinaplon) while another co-author, Dr. James M. Cook has been inventing key compounds for modulation of GABA-A receptors for several decades.

Since the FDA approval of brexanolone (Zulresso®) for post-partum depression in 2019, several new potentiators of GABA (GABAkines) have entered into the pharmaceutical pipeline. KRM-II-81, originally synthesized by Dr. Cook, is being developed by EndeavourRx, the Company’s neuromodulator business unit, because of its ability to selectively amplify inhibitory neurotransmission at a highly, specific subset of GABAA receptors, thus producing a unique efficacy profile with reduced side effects. The Company currently is focusing on developing KRM-II-81 for the treatment of epilepsy and acute and chronic pain which includes inflammatory and neuropathic pain, which we refer to simply as pain. The findings of broad antiepileptic activity in models of pharmacoresistant epilepsy and in models of pain have encouraged the development of this compound.

D5-KRM-II-81 a structurally related analog is being evaluated by EndeavourRx as a potent, and orally-bioavailable backup that will be used as needed as KRM-II-81 enters its clinical development. Doses of D5-KRM-II-81 as low as 2 mg/kg provided enduring exposure of plasma and brain of rats after oral administration. Importantly, like KRM-II-81, D5-KRM-II-81 completely prevented clonic seizures, tonic seizures, and lethality induced by the GABA receptor antagonist chemoconvulsant pentylenetetrazol. Experimental work in human epileptic brain tissue from patients that are resistant to standard of care antiepileptic medicines is ongoing.

Senior author Dr. Witkin commented, “The antiepileptic potential discovered for D5-KRM-II-81 allows this new orally-bioavailable analog to assist with our drug development efforts in pharmacoresistant epilepsy and pain. Given the large unmet medical need in both of these areas, we are excited to have this new structural analog in our hands.”

About RespireRx Pharmaceuticals Inc.

RespireRx Pharmaceuticals Inc. is a leader in the discovery and development of medicines for the treatment of psychiatric and neurological disorders, with a focus on treatments that address conditions affecting millions of people, but for which there are few or poor treatment options, including obstructive sleep apnea (“OSA”), attention deficit hyperactivity disorder (“ADHD”), epilepsy, pain and recovery from spinal cord injury (“SCI”), as well as certain neurological orphan diseases. RespireRx is developing a pipeline of new and re-purposed drug products based on our broad patent portfolios for two drug platforms: (i) pharmaceutical cannabinoids, which include dronabinol, a synthetic form of ∆9-tetrahydrocannabinol (“Δ9-THC”) that acts upon the nervous system’s endogenous cannabinoid receptors and (ii) neuromodulators, which include AMPAkines and GABAkines, proprietary chemical entities that positively modulate (positive allosteric modulators or “PAMs”) AMPA-type glutamate receptors and GABAA receptors, respectively.

The Company holds exclusive licenses and owns patents and patent applications or rights thereto for certain families of chemical compounds that claim the chemical structures and their uses in the treatment of a variety of disorders, as well as claims for novel uses of known drugs.

ResolutionRx: Pharmaceutical Cannabinoids

Dronabinol. RespireRx’s ResolutionRx business unit is developing dronabinol, ∆-9-THC, a synthetic version of the naturally occurring substance in the cannabis plant, for the treatment of OSA, a serious respiratory disorder that impacts an estimated 29.4 million people in the United States according to the American Academy of Sleep Medicine (“AASM”), published in August 2016. OSA has been linked to increased risk for hypertension, heart failure, depression, and diabetes, and has an annual economic cost in the United States of $162 billion according to the AASM. There are no approved drug treatments for OSA.

Two Phase 2 clinical trials have been completed demonstrating the ability of dronabinol to significantly reduce the symptoms of OSA and, subject to raising sufficient financing (of which no assurance can be provided) and pending the outcome of an intended meeting with the FDA, RespireRx believes that it will be able to commence a pharmacokinetic study for a recently discovered and to-be-developed formulation followed by a Phase 3 clinical study for the treatment of OSA with the new formulation. Because dronabinol is already FDA approved for the treatment of AIDS related anorexia and chemotherapy induced nausea and vomiting, the Company further believes that its re-purposing strategy would only require approval by the FDA of a 505(b)(2) new drug application (“NDA”), an efficient regulatory pathway that allows the use of publicly available data. 

EndeavourRx: Neuromodulators

GABAkines. Under a License Agreement with the University of Wisconsin-Milwaukee Research Foundation, Inc. (“UWMRF”) and on behalf of its EndeavourRx business unit, RespireRx has licensed rights to certain selectively acting GABAkines because of their ability to selectively amplify inhibitory neurotransmission at a highly specific, subset of GABAA receptors, thus producing a unique efficacy profile with reduced side effects. Preclinical studies have documented their efficacy in a broad array of animal models of interrelated neurological and psychiatric disorders including epilepsy, pain, anxiety, and depression in the absence of or with greatly reduced propensity to produce sedation, motor-impairment, tolerance, dependence and abuse. The Company currently is focusing on developing KRM-II-81 for the treatment of epilepsy and pain.

KRM-II-81 has displayed a high degree of anti-convulsant activity in a broad range of preclinical studies, including in treatment resistant and pharmaco-resistant models. Not only was KRM-II-81 highly effective in these models, but pharmaco-resistance or tolerance did not develop to its anti-convulsant properties. These latter results are particularly important because pharmaco-resistance occurs when medications that once controlled seizures lose efficacy as a result of chronic use and it is a principal reason some epileptic patients require brain surgery to control their seizures. In support of its potential clinical efficacy, translational studies have demonstrated the ability of KRM-II-81 to dramatically reduce epileptiform electrical activity when administered in situ to brain slices excised from treatment resistant epileptic patients undergoing surgery.

In addition, KRM-II-81 has displayed a high degree of analgesic activity in a broad range of preclinical studies. In intact animal models of pain, the analgesic efficacy of KRM-II-81 was comparable to or greater than commonly used analgesics. At the same time, KRM-II-81 did not display side effects such as sedation and motor impairment, but even more importantly, it did not produce tolerance, dependence, respiratory depression or behavioral changes indicative of abuse liability, which are produced by opioid narcotics and are at the heart of the opioid epidemic.

AMPAkines. Through an extensive translational research effort from the cellular level through Phase 2 clinical trials, the Company has developed a family of novel, low impact AMPAkines, including CX717, CX1739 and CX1942 that may have clinical application in the treatment of CNS-driven neurobehavioral and cognitive disorders, spinal cord injury, neurological diseases, and certain orphan indications. Our lead clinical compounds, CX717 and CX1739, have successfully completed multiple Phase 1 safety trials. Both compounds have also completed Phase 2 proof of concept trials demonstrating target engagement, by antagonizing the ability of opioids to induce respiratory depression.

AMPAkines have demonstrated positive activity in animal models of ADHD, results that have been extended translationally into statistically significant improvement of symptoms observed in a Phase 2 human clinical trial of CX717 in adults with ADHD. Statistically significant therapeutic effects were observed within one week. We believe AMPAkines may represent a novel, non-stimulant treatment for ADHD with a more rapid onset of action than alternative non stimulants, such as Straterra® (atomoxetine), and without the drawbacks of amphetamine-type stimulants.

In a series of important studies funded by grants from the National Institutes of Health and published in a number of peer reviewed articles, Dr. David Fuller (University of Florida), a long-time RespireRx collaborator, has demonstrated the ability of CX1739 and CX717, the Company’s lead AMPAkines, to improve motor nerve activity and muscle function in animal models of spinal cord injury (SCI).

Additional information about RespireRx and the matters discussed herein can be obtained on the Company’s web-site at www.RespireRx.com or in the Company’s filings with the Securities and Exchange Commission at www.sec.gov.

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Company Contact:

Jeff Margolis
Senior Vice President, Chief Financial Officer, Treasurer and Secretary
Telephone: (917) 834-7206
E-mail: jmargolis@respirerx.com
RespireRx Pharmaceuticals Inc.
126 Valley Road,
Suite C,
Glen Rock, NJ 07452
www.respirerx.com