Role of VVZ-149, a Novel Analgesic Molecule, in the Affective Component of Pain: Results from an Exploratory Proof-of-Concept Study of Postoperative Pain following Laparoscopic and Robotic-Laparoscopic Gastrectomy

Evaluation of Safety, Pharmacokinetic, and Pharmacodynamic Characteristics of a Novel Dual mGluR5/5-HT2AR Antagonist (VVZ-2471) in a Randomized, Double-Blind, First-in-Human Study

BACKGROUND

VVZ-2471 is a dual-target compound that simultaneously inhibits both metabotropic glutamate receptor subtype 5 and serotonin receptor subtype 2A. Preclinical studies have supported VVZ-2471 as a promising candidate for opioid use disorder. This study aimed to evaluate the safety and pharmacokinetic (PK)-pharmacodynamic (PD) characteristics of VVZ-2471 capsules in healthy Korean adults.

METHODS

A phase I, double blind, placebo controlled, single ascending dose (SAD) and multiple ascending dose (MAD) study was conducted in healthy adult males. In the SAD study, participants received a single oral dose of VVZ-2471 ranging from 25 to 600 mg, including a satellite food-effect group receiving 200 mg. In the MAD study, participants received 200 mg once daily (QD), 200 mg twice daily, and 400 mg QD for 7 days. Plasma and urine samples were collected for the PK analyses. Safety analysis was based on adverse events, clinical laboratory tests, vital signs, physical examinations, 12-lead electrograms, oxygen saturation monitoring, and the Beck Depression Inventory-II test. The potential of VVZ-2471 for treating addiction was explored using a well-established questionnaire on smoking urges (QSU-Brief) consisting of ten items.

RESULTS

A total of 49 and 24 healthy Korean adult males completed the SAD and MAD study, respectively. The overall demographic characteristics of participants who received VVZ-2471 or placebo in the SAD and MAD studies were generally comparable. Following a single oral dose of VVZ-2471 up to 600 mg, the area under the concentration-time curve (AUC) increased proportionally with the dose. After repeated administration, the accumulation ratio of VVZ-2471 ranged from 1.4 to 2.0. In the fed state, the maximum plasma concentration and AUC of VVZ-2471 decreased to 0.78-fold and 0.61-fold, respectively, compared with the fasting state. Urinary excretion was marginal. The most common adverse events were nausea and dizziness. Among 29 smokers, participants given VVZ-2471 at 200 mg or higher had reduced smoking urges compared with the placebo.

CONCLUSIONS

VVZ-2471 was well tolerated up to a single oral dose of 600 mg and a daily oral dose of 400 mg for 7 days. While preliminary, a trend of reducing smoking urges was observed in the VVZ-2471 group.

REGISTRATION

Clinical Research Information Service (CRiS), Republic of Korea (a primary registry in the World Health Organization (WHO) Registry Network) identifier no. KCT000889.

Reduction of postoperative pain and opioid consumption by VVZ-149, first-in-class analgesic molecule: A confirmatory phase 3 trial of laparoscopic colectomy

STUDY OBJECTIVE

VVZ-149 is a small molecule that inhibits the glycine transporter type 2 and the serotonin receptor 5-hydroxytryptamine 2 A. In this Phase 3 study, we investigated the efficacy and safety of VVZ-149 as a single-use injectable analgesic for treating moderate to severe postoperative pain after laparoscopic colectomy.

DESIGN

Randomized, parallel group, double-blind, Phase 3 clinical trial (Trial no. NCT05764525).

SETTING

5 tertiary referral centers in South Korea.

PATIENTS

284 patients undergoing laparoscopic colectomy.

INTERVENTIONS

A continuous 10-h intravenous infusion of VVZ-149 (n = 141) or placebo (n = 143) administered after emergence from anesthesia.

MEASUREMENTS

Pain intensity was assessed using a numeric rating scale (NRS) from the start of infusion for 48 h. The primary efficacy measure was the Sum of Pain Intensity Difference (SPID) for the first 12 h after the start of drug infusion. Other efficacy measures included SPID at other time points, opioid consumption via on-demand patient-controlled analgesia (PCA) and rescue medication, and proportion of patients who did not require rescue opioids for 48 h post-dose.

MAIN RESULTS

Pain relief as measured by SPID was significantly improved by 35 % in the VVZ-149 group compared to the placebo group at 6 h (p = 0.0193) and 12 h (p = 0.0047) after the start of infusion. Significantly lower pain intensity scores were observed between 4-10 h in the VVZ-149 group compared to the placebo group (p = 0.0007), reaching mild pain (mean NRS <4) at 8 h. VVZ-149 alleviated pain during the first 12 h post-dose with 30.8 % less opioid consumption and 60.2 % fewer PCA requests when compared with placebo. A higher proportion of patients receiving VVZ-149 were rescue opioid-free during 2-6 h (p = 0.0026) and 6-12 h (p = 0.0024) compared with the placebo group. VVZ-149 administration in post-colectomy patients was generally safe and well tolerated.

CONCLUSIONS

When compared to placebo, VVZ-149 infusion demonstrated a significant reduction of pain within the first 12 h after surgery with a substantial decrease in opioid use. VVZ-149 rapidly lowers the pain intensity starting at as early as 4 h post-dose, allowing subjects to experience mild pain levels from 8 h through 48 h. Therefore, the analgesic effect of VVZ-149 was shown to effectively relieve pain and reduce opioid use for treating moderate to severe pain in the early postoperative care setting.

REGISTRATION NUMBER

Trial Number NCT05764525.

Interactions Involving Glycine and Other Amino Acid Neurotransmitters: Focus on Transporter-Mediated Regulation of Release and Glycine-Glutamate Crosstalk

Glycine plays a pivotal role in the Central Nervous System (CNS), being a major inhibitory neurotransmitter as well as a co-agonist of Glutamate at excitatory NMDA receptors. Interactions involving Glycine and other neurotransmitters are the subject of different studies. Functional interactions among neurotransmitters include the modulation of release through release-regulating receptors but also through transporter-mediated mechanisms. Many transporter-mediated interactions involve the amino acid transmitters Glycine, Glutamate, and GABA. Different studies published during the last two decades investigated a number of transporter-mediated interactions in depth involving amino acid transmitters at the nerve terminal level in different CNS areas, providing details of mechanisms involved and suggesting pathophysiological significances. Here, this evidence is reviewed also considering additional recent information available in the literature, with a special (but not exclusive) focus on glycinergic neurotransmission and Glycine-Glutamate interactions. Some possible pharmacological implications, although partly speculative, are also discussed. Dysregulations in glycinergic and glutamatergic transmission are involved in relevant CNS pathologies. Pharmacological interventions on glycinergic targets (including receptors and transporters) are under study to develop novel therapies against serious CNS pathological states including pain, schizophrenia, epilepsy, and neurodegenerative diseases. Although with limitations, it is hoped to possibly contribute to a better understanding of the complex interactions between glycine-mediated neurotransmission and other major amino acid transmitters, also in view of the current interest in potential drugs acting on "glycinergic" targets.

Comprehensive review of amino acid transporters as therapeutic targets

The solute carrier (SLC) family, with more than 400 membrane-bound proteins, facilitates the transport of a wide array of substrates such as nutrients, ions, metabolites, and drugs across biological membranes. Amino acid transporters (AATs) are membrane transport proteins that mediate transfer of amino acids into and out of cells or cellular organelles. AATs participate in many important physiological functions including nutrient supply, metabolic transformation, energy homeostasis, redox regulation, and neurological regulation. Several AATs have been found to significantly impact the progression of human malignancies, and dysregulation of AATs results in metabolic reprogramming affecting tumor growth and progression. However, current clinical therapies that directly target AATs have not been developed. The purpose of this review is to highlight the structural and functional diversity of AATs, the molecular mechanisms in human diseases such as tumors, kidney diseases, and emerging therapeutic strategies for targeting AATs.

Analysis of Binding Determinants for Different Classes of Competitive and Noncompetitive Inhibitors of Glycine Transporters

Glycine transporters are interesting therapeutic targets as they play significant roles in glycinergic and glutamatergic systems. The search for new selective inhibitors of particular types of glycine transporters (GlyT-1 and GlyT-2) with beneficial kinetics is hampered by limited knowledge about the spatial structure of these proteins. In this study, a pool of homology models of GlyT-1 and GlyT-2 in different conformational states was constructed using the crystal structures of related transporters from the SLC6 family and the recently revealed structure of GlyT-1 in the inward-open state, in order to investigate their binding sites. The binding mode of the known GlyT-1 and GlyT-2 inhibitors was determined using molecular docking studies, molecular dynamics simulations, and MM-GBSA free energy calculations. The results of this study indicate that two amino acids, Gly373 and Leu476 in GlyT-1 and the corresponding Ser479 and Thr582 in GlyT-2, are mainly responsible for the selective binding of ligands within the S1 site. Apart from these, one pocket of the S2 site, which lies between TM3 and TM10, may also be important. Moreover, selective binding of noncompetitive GlyT-1 inhibitors in the intracellular release pathway is affected by hydrophobic interactions with Ile399, Met382, and Leu158. These results can be useful in the rational design of new glycine transporter inhibitors with desired selectivity and properties in the future.

Emerging drugs for the treatment of postsurgical pain

INTRODUCTION

Postoperative pain is a distressful experience and remains to be a significant concern after surgery. Current agents either fail to prevent or minimize postoperative pain or cause a series of adverse effects, addiction, or abuse. Opioids have been the gold standard in the treatment of postoperative pain despite their well-described adverse effects. Many new agents with different mechanisms of action have been recently introduced to address this issue.

AREAS COVERED

This current review summarizes the list of new and emerging drugs investigated for their efficacy in controlling the postoperative pain and decreasing the need for rescue opioid use, adverse effect profile, abuse, and addiction potential.

EXPERT OPINION

Opioids have unrivaled analgesic efficacy. However adverse effects of opioids led to the search for better options. In mild pain most of the emerging drugs have been shown to control postoperative pain and decrease the use of rescue opioid, however fail to control pain after major surgeries causing severe pain. Specific agents such as Oliceridine, new local anesthetics, etc., are effective in controlling severe pain and hold a promise to replace opioids in the near future.

Inhibition of Glycine Re-Uptake: A Potential Approach for Treating Pain by Augmenting Glycine-Mediated Spinal Neurotransmission and Blunting Central Nociceptive Signaling

Among the myriad of cellular and molecular processes identified as contributing to pathological pain, disinhibition of spinal cord nociceptive signaling to higher cortical centers plays a critical role. Importantly, evidence suggests that impaired glycinergic neurotransmission develops in the dorsal horn of the spinal cord in inflammatory and neuropathic pain models and is a key maladaptive mechanism causing mechanical hyperalgesia and allodynia. Thus, it has been hypothesized that pharmacological agents capable of augmenting glycinergic tone within the dorsal horn may be able to blunt or block aberrant nociceptor signaling to the brain and serve as a novel class of analgesics for various pathological pain states. Indeed, drugs that enhance dysfunctional glycinergic transmission, and in particular inhibitors of the glycine transporters (GlyT1 and GlyT2), are generating widespread interest as a potential class of novel analgesics. The GlyTs are Na⁺/Cl⁻-dependent transporters of the solute carrier 6 (SLC6) family and it has been proposed that the inhibition of them presents a possible mechanism by which to increase spinal extracellular glycine concentrations and enhance GlyR-mediated inhibitory neurotransmission in the dorsal horn. Various inhibitors of both GlyT1 and GlyT2 have demonstrated broad analgesic efficacy in several preclinical models of acute and chronic pain, providing promise for the approach to deliver a first-in-class non-opioid analgesic with a mechanism of action differentiated from current standard of care. This review will highlight the therapeutic potential of GlyT inhibitors as a novel class of analgesics, present recent advances reported for the field, and discuss the key challenges associated with the development of a GlyT inhibitor into a safe and effective agent to treat pain.

Modulation of Glycinergic Neurotransmission may Contribute to the Analgesic Effects of Propacetamol

Treating neuropathic pain remains challenging, and therefore new pharmacological strategies are urgently required. Here, the enhancement of glycinergic neurotransmission by either facilitating glycine receptors (GlyR) or inhibiting glycine transporter (GlyT) function to increase extracellular glycine concentration appears promising. Propacetamol is a N,N-diethylester of acetaminophen, a non-opioid analgesic used to treat mild pain conditions. In vivo, it is hydrolysed into N,N-diethylglycine (DEG) and acetaminophen. DEG has structural similarities to known alternative GlyT1 substrates. In this study, we analyzed possible effects of propacetamol, or its metabolite N,N-diethylglycine (DEG), on GlyRs or GlyTs function by using a two-electrode voltage clamp approach in Xenopus laevis oocytes. Our data demonstrate that, although propacetamol or acetaminophen had no effect on the function of the analysed glycine-responsive proteins, the propacetamol metabolite DEG acted as a low-affine substrate for both GlyT1 (EC50 > 7.6 mM) and GlyT2 (EC50 > 5.2 mM). It also acted as a mild positive allosteric modulator of GlyRα1 function at intermediate concentrations. Taken together, our data show that DEG influences both glycine transporter and receptor function, and therefore could facilitate glycinergic neurotransmission in a multimodal manner.