If You Invested in Respirerx Pharma (RSPI)

RespireRx Pharmaceuticals Inc. (RSPI), together with its subsidiaries EndeavourRx LLC and ResolutionRx Ltd, collectively referred to as the RespireRx Group, is focused on the discovery and development of medicines for the treatment of psychiatric and neurological disorders. According to company disclosures, the group concentrates on conditions for which there are few or poor treatment options, including epilepsy, pain, attention deficit hyperactivity disorder (ADHD), recovery from spinal cord injury (SCI), certain neurological orphan diseases and obstructive sleep apnea (OSA). The company is classified under Pharmaceutical Preparation Manufacturing within the broader manufacturing sector.

The RespireRx Group is building a pipeline of new and repurposed drug product candidates based on broad patent portfolios for two main drug platforms. The first platform comprises neuromodulators, including GABAkines and AMPAkines, which are proprietary chemical entities that positively modulate (positive allosteric modulators or PAMs) GABAA receptors and AMPA-type glutamate receptors, respectively. These neuromodulator programs are organized primarily within EndeavourRx LLC. The second platform consists of pharmaceutical cannabinoids, centered on dronabinol, a synthetic compound that acts upon the nervous system’s endogenous cannabinoid receptors, and is advanced within ResolutionRx Ltd. The group states that it holds exclusive licenses and owns patents and patent applications, or rights thereto, for families of chemical compounds and their uses in the treatment of a variety of disorders, as well as claims for novel uses of known drugs.

Business structure and core programs

RespireRx Pharmaceuticals Inc. is the Delaware parent company of the RespireRx Group. It has created distinct entities to advance specific technology platforms and therapeutic programs. ResolutionRx Ltd was formed in Australia as an unlisted public company to pursue the company’s obstructive sleep apnea drug development program based on dronabinol. EndeavourRx LLC, a Delaware limited liability company, was formed as a wholly owned subsidiary to house neuromodulator programs based on AMPAkines and GABAkines. Certain therapeutic opportunities are retained directly at RespireRx.

EndeavourRx LLC – Neuromodulators

Within EndeavourRx, RespireRx has developed a family of low-impact AMPAkines, including CX717, CX1739 and CX1942, through translational research from the cellular level through Phase 2 clinical trials. Company materials describe potential clinical applications in CNS-driven neurobehavioral and cognitive disorders, spinal cord injury, neurological diseases and certain orphan indications. Lead clinical AMPAkines CX717 and CX1739 have completed multiple Phase 1 safety trials and Phase 2 proof-of-concept trials demonstrating target engagement by antagonizing the ability of opioids to induce respiratory depression. AMPAkines have shown positive activity in animal models of ADHD, and a Phase 2 clinical trial of CX717 in adult ADHD patients reported statistically significant improvement of symptoms within one week.

Preclinical and translational work, including studies led by academic collaborators, has shown that CX1739 and CX717 can improve motor nerve activity and muscle function in animal models of SCI, including effects on respiration and bladder function. A Department of Defense translational research award has been approved to fund a two-stage Phase 2A/2B clinical study of CX1739 in individuals with spinal cord injury to assess safety and efficacy in improving bladder function and motor activity. RespireRx has also reported peer-reviewed publications demonstrating that CX1739 restored bladder function in rodent models of SCI.

The GABAkine program within EndeavourRx is based on selectively acting GABAA receptor potentiators, in-licensed under agreements with the University of Wisconsin-Milwaukee Research Foundation, Inc. (UWMRF). These compounds are described as selectively amplifying inhibitory neurotransmission at specific subsets of GABAA receptors, with preclinical studies documenting efficacy in animal models of epilepsy, pain, anxiety and depression, with greatly reduced propensity for sedation, motor impairment, tolerance, dependence and abuse. The lead GABAkine candidate, KRM-II-81, has demonstrated a high degree of anti-convulsant activity in a broad range of preclinical models, including treatment-resistant and pharmaco-resistant epilepsy models, without development of pharmaco-resistance or tolerance to its anti-convulsant properties. Translational studies have shown that KRM-II-81 can dramatically reduce epileptiform electrical activity in brain slices excised from treatment-resistant epileptic patients who underwent surgery.

KRM-II-81 has also exhibited a high degree of analgesic activity in multiple preclinical pain models, including acute, chronic and neuropathic pain, with analgesic efficacy comparable to or greater than commonly used analgesics in intact animal models. Company disclosures emphasize that KRM-II-81 did not produce side effects such as sedation and motor impairment and did not show tolerance, dependence, respiratory depression or behavioral changes indicative of abuse liability in these models. KRM-II-81 has advanced within the NIH HEAL Initiative Preclinical Screening Platform for Pain, where emerging data have shown anti-pain effects in rat models at doses with minimal or no detectable side effects.

RespireRx has also reported a case study in which KRM-II-81 fully suppressed epileptiform bursting in cortical tissue surgically removed from a pharmaco-resistant epileptic patient when added to the incubation fluid, with epileptiform activity returning upon removal of the compound. This finding is presented by the company as translational support for the potential of KRM-II-81 in treatment-resistant epilepsy.

ResolutionRx Ltd – Pharmaceutical cannabinoids

ResolutionRx Ltd was formed in Australia as an unlisted public company to develop pharmaceutical cannabinoid therapies, initially focusing on a new formulation of dronabinol for obstructive sleep apnea. RespireRx has contributed its OSA drug development program to ResolutionRx by sublicense and license, subject to certain liabilities. ResolutionRx is responsible for research and development associated with this program, including development of a new dronabinol formulation intended for use in pharmacokinetic and pharmacodynamic studies and a planned Phase 3 clinical trial, followed by regulatory filings for OSA treatment.

Dronabinol, described as an endocannabinoid receptor agonist, has already demonstrated significant improvement in OSA symptoms in two Phase 2 clinical trials, according to company communications. OSA is characterized in these materials as a serious respiratory disorder affecting large patient populations in the United States, Australia, the United Kingdom and Germany, with associations to hypertension, heart failure, depression and diabetes, and with no approved drug treatments. The company notes that dronabinol is already approved by the U.S. Food and Drug Administration for AIDS-related anorexia and chemotherapy-induced nausea and vomiting, and that RespireRx and ResolutionRx believe a repurposing strategy could proceed in the United States via a 505(b)(2) new drug application pathway, which allows reliance on publicly available data. Company statements also reference similar regulatory strategies in the European Union.

ResolutionRx’s development plan includes reliance on the Australian Research and Development Tax Incentive, under which a significant percentage of qualified R&D expenditures may be refunded. Company disclosures describe arrangements with an Australia-based fund to finance a portion of anticipated tax credits and late-stage negotiations with an investor for equity or equity-linked financing tied to approved Australian vendors. ResolutionRx has also indicated an intent to list on the Australian Securities Exchange and potentially on one or more exchanges outside Australia.

Research focus and disease areas

Across its platforms, the RespireRx Group targets psychiatric and neurological disorders where unmet medical need is emphasized in its communications. These include:

• Epilepsy, including treatment-resistant forms, through GABAkines such as KRM-II-81.
• Pain, with a focus on non-opioid analgesic approaches using GABAkines.
• Attention deficit hyperactivity disorder (ADHD), through AMPAkines such as CX717 and CX1739, which have shown activity in animal models and in a Phase 2 trial in adults with ADHD.
• Recovery from spinal cord injury (SCI), including motor and bladder function, via AMPAkines like CX1739 and CX717.
• Obstructive sleep apnea (OSA), via repurposed dronabinol formulations under ResolutionRx.
• Certain neurological orphan diseases, as referenced in company descriptions of its target indications.

The company’s communications repeatedly highlight collaborations with academic and clinical institutions, including the University of Florida, Shirley Ryan AbilityLab and institutions associated with the NIH HEAL Initiative. These collaborations underpin preclinical and translational research supporting the AMPAkine and GABAkine programs.

Regulatory and trading status

RespireRx has disclosed that its common stock previously traded on the OTC Pink Market under the ticker RSPI. Company press releases report that the U.S. Securities and Exchange Commission initiated an administrative proceeding under Section 12(j) of the Securities Exchange Act of 1934 due to the company’s failure to file periodic reports after a Form 10-Q for the period ended September 30, 2023. Following an Offer of Settlement by RespireRx, the SEC issued an Order Making Findings and Revoking Registration of Securities Pursuant to Section 12(j), effective November 14, 2025. The order revoked the registration of each class of securities of RespireRx registered under Section 12 of the Exchange Act. Company statements note that there was no monetary fine and that quotations of the common stock had been submitted on the Expert Market of the OTC Link ATS prior to the revocation.

RespireRx has publicly discussed plans to seek re-registration of its common stock, and possibly other classes of stock, via a Form 10 filing under Section 12(g) of the Exchange Act, which would require two years of audited financial statements. These plans are described by the company as subject to various conditions and uncertainties, and the company cautions that it can provide no assurance that such steps will occur.

Capital formation and corporate strategy

Company communications describe capital-raising as a significant challenge. RespireRx has outlined strategies that include the use of preferred stock structures and the creation of separate subsidiaries to facilitate asset-level financing and risk separation. The company has amended and restated certificates of designation for certain preferred stock series to adjust terms such as designated share counts, base measurement prices, maximum appreciated prices and definitions of eligible payment events tied to licensing, milestone payments, royalties or other transactions.

In more recent disclosures, the RespireRx Group announced the commencement of a Regulation D, Rule 506(c) exempt private placement across RespireRx, EndeavourRx LLC and ResolutionRx Ltd, with a targeted aggregate raise and an exclusive placement agent. The stated use of proceeds includes funding research and development and clinical programs across the three entities, advancing the dronabinol OSA program at ResolutionRx, progressing AMPAkine and GABAkine programs at EndeavourRx, and supporting corporate operations, governance and intellectual property management at the parent company.

Grants, collaborations and intellectual property

RespireRx has reported multiple non-dilutive funding sources and collaborations. These include a Department of Defense translational research award to Shirley Ryan AbilityLab for a Phase 2A/2B clinical study of CX1739 in SCI patients, with RespireRx responsible for manufacturing and formulating clinical material and managing the investigational new drug (IND) application. The company has also received a Notice of Award from the National Institutes of Health (NIH), National Institute of Neurological Disorders and Stroke (NINDS), under the Small Business Innovation Research (SBIR) program to support preclinical toxicology and related efforts required for an IND filing for KRM-II-81 in epilepsy.

In addition, KRM-II-81 has advanced within the NIH HEAL Initiative Preclinical Screening Platform for Pain, which evaluates non-opioid assets in established preclinical pain models. Company disclosures also describe an amended and restated patent license agreement with the University of Wisconsin-Milwaukee Research Foundation, Inc. that revises regulatory milestone-based payments, royalty structures, patent cost reimbursements and equity provisions, with the aim of aligning with current commercialization strategies for GABAkines.

The RespireRx Group emphasizes that it holds exclusive licenses and owns patents and patent applications covering chemical structures, therapeutic uses and novel uses of known drugs across its neuromodulator and cannabinoid platforms. These intellectual property positions are presented as central to the company’s ability to develop and potentially commercialize its drug candidates.

Company status considerations

Based on the company’s own press releases, RespireRx continues to describe itself as engaged in research and development through the RespireRx Group, including EndeavourRx LLC and ResolutionRx Ltd. At the same time, the SEC’s Section 12(j) order has revoked the registration of its securities under the Exchange Act, and the company has acknowledged that its common stock had been quoted on the Expert Market of the OTC Link ATS. Investors reviewing RSPI should recognize that the ticker’s regulatory status has changed and that any plans to re-register securities or resume broader trading are subject to uncertainties described by the company in its forward-looking statements and risk factor discussions.

FAQs about RespireRx Pharmaceuticals Inc. (RSPI)