NRx Pharmaceuticals, Inc. announced that FDA has given the company clearance to proceed with human trials to treat Chronic Pain under the Investigational New Drug (IND) application filed with the U.S. Food and Drug Administration (FDA) for the use of NRX-101. The IND application leverages pioneering research on the use of D-cycloserine (a key ingredient of NRX-101) in the treatment of chronic pain and the recent licensure by NRx of a US Patent for the use of D-cycloserine in the treatment of pain. NRX-101 in Chronic Pain Chronic pain is estimated to be a $72 billion industry with the potential to grow to a $120 billion industry by 2033.

In June 2023, concurrent with announcement of the Alvogen partnership, the Company announced an expansion of its NRX-101 program to encompass treatment of chronic pain as the next focus on NRX-101's development. The company has announced the licensure of US Patent 8,653,120 related to the treatment of chronic pain with DCS and the addition of Dr. Apkar Vania Apkarian, Professor of Physiology, Anesthesia, Surgery, and Neuroscience Institute, Northwestern University Feinberg School of Medicine, to the NRx Scientific Advisory Board. Dr. Apkarian is the inventor of the patent and a global expert in pain research and has important experience studying DCS in chronic pain.

D-cycloserine (DCS) has been shown to modulate the Pain Pathway at each point in the neural chain of pain: transmission at dorsal horn of the spinal cord, pain perception in the thalamus ("paleo brain"), and pain memory and processing between the paleo brain and the cortex. In experimental models and clinical studies, NMDA antagonists have demonstrated attenuation of pain and shown potential to reduce opioid craving. DCS has demonstrated no potential for addiction, unlike ketamine and other NMDA antagonists that bind to the "mu" opioid receptor.

DCS was evaluated in a pilot study at Northwestern University and showed efficacy at the higher dose levels in the study (Schnitzer, 2016). DCS is currently being examined in a confirmatory trial funded by the US Department of Defense under the Congressionally Directed Medical Research Program. The trial seeks to recruit approximately 200 participants with chronic low back pain at Northwestern University (clinicaltrials.gov NCT03535688). Data collection is complete and statistical results are expected in the coming months.

Research conducted by NRx Pharmaceuticals demonstrated a 25 µg/ml dose at which D-cycloserine becomes an NMDA antagonist. The 400mg dose presented in the confirmatory trial at Northwestern University is at the lower end of the threshold and suggests that the ability to increase the D-cycloserine dose beyond 400mg, where lurasidone is used to prevent CNS side effects in NRX-101.