Table 3.

Nav1.7 is the Gene Expression of the SCN9A in Humans

Status	Study Title	Conditions	Interventions	Phase	Sponsor/Collaborators	Locations
Completed	Safety and Tolerability of Lacosamide in Patients With Gain-of-function Nav1.7 Mutations Related Small Fiber Neuropathy	Small Fiber Neuropathy	Drug: Lacosamide Drug: Placebo	Phase 3	Academisch Ziekenhuis Maastricht	Maastricht University Medical Center Maastricht, Netherlands
Completed Has Results	Carbamazepine for Inherited Erythromelalgia Patients With NaV1.7 Mutations	Erythromelalgia	Drug: Carbamazepine Drug: Placebo	Phase 4	VA Connecticut Healthcare System	Yale University New Haven, Connecticut, United States VA Connecticut Healthcare System West Haven, Connecticut, United States
Completed	The Impact of the SCN9A Gene Polymorphism on Postoperative Pain	Pain, Postoperative Pregnancy	Procedure: cesarean section Drug: Opioid Tramadol		Tokat Gaziosmanpasa University	Gaziosmanpasa University Medical School Hospital Tokat, Turkey
Completed Has Results	The Impact of SCN9A Gene Polymorphism on Individual Pain Perception in the General Population	Pain Surgery			Xianwei Zhang Huazhong University of Science and Technology	Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, Hubei, China
Unknown †	Probing the Role of Sodium Channels in Painful Neuropathies	Painful Peripheral Neuropathy Painless Peripheral Neuropathy			Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta Maastricht University Yale University (and 4 more.)
Recruiting	Depolarising Electrical Skin Stimulation in Neuropathic and Postoperative Pain	Neuropathy; Peripheral	Diagnostic Test: neurophysiology		Swiss Paraplegic Centre Nottwil	Centre for Pain Medicine Nottwil, Switzerland
Completed Has Results	Use of Topical Lidocaine to Reduce Pain in Patients With Diabetic Neuropathy	Diabetic Peripheral Neuropathy	Procedure: Skin biopsy Drug: Lidocaine 5% patches	Phase 2 Phase 3	Albany Medical College Endo Pharmaceuticals	Albany Medical College Albany, New York, United States
Recruiting	fMRI-study in Patients With Small Fiber Neuropathy	Small Fiber Neuropathy	Diagnostic Test: functional MRI		Academisch Ziekenhuis Maastricht Harvard University	Maastricht University Medical Center Maastricht, Netherlands
Completed Has Results	A Clinical Trial To Evaluate PF-05089771 On Its Own And As An Add-On Therapy To Pregabalin (Lyrica) For The Treatment Of Pain Due To Diabetic Peripheral Neuropathy (DPN)	Diabetic Neuropathy, Painful	Drug: PF-05089771 150 mg Drug: Matched placebo for PF-05089771 150 mg and pregabalin 300 mg Drug: Pregabalin 300 mg Drug: PF-05089771 150 mg + Pregabalin 300 mg	Phase 2	Pfizer	Clinical Research Consortium Arizona Phoenix, Arizona, United States Arizona Research Center Phoenix, Arizona, United States Neuro-Pain Medical Center Fresno, California, United States (and 29 more.)
Completed	Classical Trigeminal Neuralgia and Sodium Channel Mutations	Trigeminal Neuralgia	Other: Observational		Danish Headache Center Maastricht University Medical Center
Recruiting	A SAD Study to Evaluate the Safety, Tolerability and PK/PD of iN1011-N17 in Healthy Volunteers	Osteoarthritis Pain	Drug: iN1011-N17 Drug: Placebo	Phase 1	iN Therapeutics Co., Ltd.	Nucleus Network, Melbourne, Victoria, Australia
Active, not recruiting	Evaluation And Risk Assessment For Persistent Postsurgical Pain After Breast Surgery	Breast Cancer Chronic Pain Acute Pain Depression, Anxiety	Other: Questionnaires Other: Mechanical Temporal Summation assessment Other: Pain threshold assessment		KK Women’s and Children’s Hospital Duke University	Duke University Medical Center, Durham, North Carolina, United States KK Women’s and Children’s Hospital, Singapore, Singapore

Notes: This 115 amino acid protein sodium ion channel is found within neurons at high levels. It is specifically nociceptive (pain) neurons located within the dorsal root ganglia, trigeminal ganglia, and the sympathetic ganglia neurons. The table information from the http://www.clinicaltrials.gov dated December 18, 2022 indicate the records of 12 human clinical studies targeting Nav1.7. The above clinical trials that have results is again showing the inconclusively of the effectiveness of small molecules in the treatment of pain via the targeting of Nav1.7. Therefore, it is the conclusion based on the human clinical trial that continue pursuit of the treatment of chronic in using the target of Nav1.7 by small molecule has not been successful. Therefore, there is a need for other approaches, such as focus gene therapy, which could target Nav1.7 more succinctly and thereby bring the relief of many patients that are suffering from chronic pain. Both the gene SCN9A and it protein expression Nav1.7 are vital targets which could be helpful in the development of alternative opioid treated chronic pain.