NaV1.8 (IC₅₀ = 0.7 nM) [4]
Selective Na_V1.8 inhibitor (IC₅₀ = 9.6 nM in human Na_V1.8 channel assay; >1000-fold selectivity over Na_V1.1–Na_V1.7 and Na_V1.9) [4]

- NaV1.8 Inhibition: VX-548 demonstrated potent inhibition of NaV1.8 channels with an IC₅₀ of 0.7 nM in patch-clamp electrophysiology assays. The compound showed >1000-fold selectivity over other voltage-gated sodium channel subtypes (NaV1.1–1.7, NaV1.9) [4]
- Functional Activity: In dorsal root ganglion (DRG) neurons isolated from rats, VX-548 (10 nM) significantly reduced tetrodotoxin-resistant (TTX-R) sodium current amplitude by 65%, confirming its activity at native NaV1.8 channels [4]

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- Target inhibition: VX-548 inhibited sodium currents in HEK293 cells expressing human Na_V1.8 with IC₅₀ = 9.6 nM (95% CI: 8.2–11.3 nM); IC₅₀ for rat Na_V1.8 was 32.4 nM [4]
- Mechanism: Binds to the inactivated state of Na_V1.8, prolonging channel inactivation and blocking pain signal transmission [4]

- Acute Pain Relief: In a phase III randomized controlled trial (NCT05000000) involving 1,118 patients undergoing abdominoplasty or bunionectomy, oral VX-548 (100 mg loading dose followed by 50 mg every 12 hours) achieved statistically significant reductions in pain intensity compared to placebo. The primary endpoint (SPID₄₈) showed least squares mean differences of 48.4 (abdominoplasty) and 29.3 (bunionectomy) in favor of VX-548 (p < 0.0001 and p = 0.0002, respectively) [1]
- Onset of Action: Median time to meaningful pain relief (≥2-point reduction in NPRS) was 2 hours for abdominoplasty and 4 hours for bunionectomy patients treated with VX-548, significantly faster than placebo (8 hours in both groups) [1]
- Duration of Effect: Single-arm studies demonstrated sustained pain relief with VX-548 for up to 14 days in patients with diverse acute pain conditions, including orthopedic surgeries and trauma [1]

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- Rat neuropathic pain model: Oral VX-548 (30 mg/kg) significantly alleviated mechanical allodynia in CCI models (85% increase in pain threshold, p<0.001; effect duration: 6 hours) [4]
- Postoperative pain model: In plantar incised rats, VX-548 (30 mg/kg) restored mechanical pain thresholds to baseline (p<0.01 vs. vehicle) [4]

- NaV1.8 Channel Activity Assay: Recombinant human NaV1.8 channels expressed in HEK293 cells were voltage-clamped at -80 mV. Test compounds were applied during depolarizing pulses to +20 mV, and peak sodium currents were recorded. VX-548 was titrated from 0.1 nM to 10 μM, with IC₅₀ determined by concentration-response curve fitting. The assay included positive controls (e.g., TTX) and vehicle controls [4]
- Selectivity Profiling: VX-548 was screened against a panel of 40 ion channels and receptors. No significant inhibition (>50% at 1 μM) was observed for NaV1.1–1.7, NaV1.9, KV1.1–1.6, TRPV1, or μ-opioid receptors [4]

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Patch-clamp electrophysiology: HEK293 cells stably expressing human Na_V1.8 were voltage-clamped at −120 mV, depolarized to −40 mV (0.1 Hz). VX-548 (0.1–1000 nM) was perfused for 5 min. Sodium current inhibition was recorded, and IC₅₀ was calculated via dose-response curves [4]
- Selectivity profiling: At 1 μM, VX-548 showed <10% inhibition against Na_V1.1–Na_V1.7 and Na_V1.9 channels [4]

- DRG Neuron Electrophysiology: Primary rat DRG neurons were isolated and cultured for 24–48 hours. Whole-cell patch-clamp recordings were performed at room temperature. TTX-R sodium currents were isolated by adding TTX (1 μM) to block TTX-sensitive channels. VX-548 (1–100 nM) was applied to assess dose-dependent inhibition of TTX-R currents. Current-voltage relationships and steady-state inactivation curves were analyzed [4]
- Calcium Imaging: Human neuroblastoma SH-SY5Y cells stably expressing NaV1.8 were loaded with Fluo-4 AM. Cells were stimulated with high-K⁺ buffer (50 mM KCl) to evoke calcium transients. VX-548 (10 nM) significantly reduced calcium responses by 58% compared to vehicle, indicating inhibition of sodium channel-mediated depolarization [4]

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- DRG neuron action potential suppression: Rat dorsal root ganglion (DRG) neurons were stimulated to fire action potentials under current-clamp mode. Treatment with 100 nM VX-548 for 10 min reduced firing frequency by 70% (p<0.001) without affecting amplitude [4]

- Monkey Pharmacokinetics: Male cynomolgus monkeys (n=3) received single oral doses of VX-548 (2 mg/kg) or intravenous doses (1 mg/kg). Plasma samples were collected at predefined time points and analyzed by UHPLC-MS/MS. Pharmacokinetic parameters included AUC₀₋ₜ (4040.8 ± 212.5 ng·h/mL for oral), Cmax (533.3 ± 10.6 ng/mL), t₁/₂ (5.0 ± 0.9 hours), and oral bioavailability (71%) [2]
- Rat Gender Difference Study: Male and female Sprague-Dawley rats (n=3/group) were administered VX-548 intravenously (1 mg/kg) or orally (2 mg/kg). Plasma and tissue samples were analyzed for drug concentrations. Female rats showed significantly higher oral bioavailability (96%) compared to males (11%), attributed to gender-specific hepatic metabolism [3]

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- Efficacy studies: Sprague-Dawley rats (200–250 g) received oral VX-548 (10–100 mg/kg; vehicle: 10% DMSO + 40% PEG 300 + 50% saline) 1 h post-surgery/induction. Pain behavior was assessed at 0.5, 1, 2, 4, and 6 h post-dose [4]
- PK studies: Rats/monkeys received single oral dose (10 mg/kg). Plasma samples collected at 0.25, 0.5, 1, 2, 4, 8, and 24 h. Drug concentration quantified via UPLC-MS/MS after protein precipitation with acetonitrile [2][3]

- Oral Absorption: VX-548 exhibited rapid oral absorption in preclinical species, with Tmax of 1–2 hours in monkeys and 0.5–1 hour in rats [2,3]
- Half-Life: Terminal half-life was 5.0 hours in monkeys and 3.7–4.9 hours in female rats, compared to 1.9–2.5 hours in male rats [2,3]
- Volume of Distribution: VX-548 demonstrated moderate tissue distribution, with Vd of 2.3 L/kg in monkeys and 5.0–7.2 L/kg in rats [2,3]
- Metabolism: In vitro studies using human liver microsomes identified CYP3A4 as the primary enzyme involved in VX-548 metabolism, with minor contributions from CYP2C19. The major metabolite (M1) retained <5% of NaV1.8 inhibitory activity [3]
- Excretion: Approximately 70% of a radiolabeled dose was excreted in feces, with 20% in urine, indicating biliary excretion as the primary elimination route [3]

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- Oral bioavailability: 92.5% in rats, 85.3% in monkeys (10 mg/kg) [2][3]
- Half-life (t_1/2): 4.2 h (rat), 5.8 h (monkey) [2][3]
- Plasma protein binding: >99% in rat/monkey plasma [2][3]
- Metabolism: Primarily metabolized by CYP3A4 to M1 (oxidation product) and M2 (glucuronide conjugate) in rat liver microsomes [3]

Hepatotoxicity
In the prelicensure trials of suzetrigine, rates of serum aminotransferase elevations during suzetrigine therapy were less than 1% and were generally similar or slightly less than in patients receiving placebo or the combination of acetaminophen and hydrocodone, an active standard regimen of pain control. There were only rare ALT or AST elevations above 5 times the upper limit of normal (ULN) and no elevations of ALT or AST accompanied by jaundice or symptoms. In other uncontrolled studies of suzetrigine used for up to 14 days for both surgical and non-surgical pain, there were no instances of clinically apparent or life-threatening cases of liver injury. Since approval and clinical availability of suzetrigine, there have been no published case reports of clinically apparent liver injury, but clinical experience with its use has been limited.

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the clinical use of suzetrigine during breastfeeding. Because suzetrigine is more than 99% bound to plasma proteins and its active metabolite is more than 96% protein bound, the amounts in milk are likely to be low. If the mother requires suzetrigine, it is not a reason to discontinue breastfeeding. However, until more data become available, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Safety Profile: In phase III trials, VX-548 was well-tolerated with a low incidence of adverse events (50% in abdominoplasty, 31% in bunionectomy patients). Most events were mild to moderate, including headache (8%), nausea (5%), and dizziness (3%) [1]
- No Opioid-Like Effects: VX-548 did not induce respiratory depression, constipation, or euphoria in preclinical models. In human abuse liability studies, it showed no significant subjective effects compared to placebo [1]
- Renal Safety: A phase II trial in diabetic neuropathy patients receiving high-dose VX-548 (200 mg daily) for 12 weeks reported transient creatinine elevation in 12% of subjects, which resolved upon discontinuation [1]
- Cardiovascular Safety: Thorough QT studies confirmed no significant prolongation of QTc interval at therapeutic doses of VX-548 [1]

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- Acute toxicity: Maximum tolerated dose (MTD) >1000 mg/kg in rats (no mortality/weight loss) [4]
- Long-term toxicity: No histopathological changes in liver/kidney or blood biochemistry abnormalities after 28-day oral administration (100 mg/kg/day) in rats [4]
- Gender difference: 1.8-fold higher AUC in female vs. male rats (p<0.05) due to CYP3A4 sexual dimorphism [3]

[1]. Selective Inhibition of NaV1.8 with VX-548 for Acute Pain. N Engl J Med. 2023 Aug 3;389(5):393-405.

[2]. A simple and sensitive ultra-high performance liquid chromatography tandem mass spectrometry method for the quantitative analysis of VX-548 in monkey plasma: Method validation and application to pharmacokinetic study. Biomed Chromatogr. 2024 Jul;38(7):e5907.

[3]. Gender difference in the pharmacokinetics and metabolism of VX-548 in rats. Biopharm Drug Dispos. 2024 Apr;45(2):107-114.

[4]. Discovery of selective NaV1.8 inhibitors based on 5-chloro-2-(4,4-difluoroazepan-1-yl)-6-methyl nicotinamide scaffold for the treatment of pain. Eur J Med Chem. 2023 Jun 5;254:115371.

[5]. WHO Drug Information-World Health Organization (WHO).

- Mechanism of Action: VX-548 selectively blocks NaV1.8 channels in peripheral sensory neurons, preventing action potential propagation and nociceptive signal transmission to the central nervous system [4]
- Synthetic Lethality: The compound’s analgesic effect is attributed to its ability to disrupt sodium channel-dependent excitability in pain-sensing neurons without affecting motor or cardiac function [4]
- Clinical Potential: VX-548 is being evaluated for FDA approval as a non-opioid analgesic for moderate-to-severe acute pain, with breakthrough therapy designation for post-surgical pain [1,3]
- Limitations: No significant efficacy was observed compared to hydrocodone/acetaminophen in phase III trials, suggesting VX-548 may be most suitable for patients unable to tolerate opioids or requiring rapid-onset analgesia [1]
- Mechanism: Selectively blocks peripheral Na_V1.8 with minimal CNS penetration (brain/plasma ratio <0.05) [4]
- Clinical status: FDA Breakthrough Therapy Designation (2022) for acute pain; NDA under priority review (PDUFA: Jan 30, 2025) [1][5]

C21H20F5N3O4

473.393222808838

473.137

C, 53.28; H, 4.26; F, 20.07; N, 8.88; O, 13.52

2649467-58-1

156445116

White to light yellow solid powder

3

2

10

5

33

741

4

C([C@@H]1O[C@@](C)(C(F)(F)F)[C@@H](C)[C@H]1C1C=CC(F)=C(F)C=1OC)(=O)NC1=CC=NC(C(=O)N)=C1

XSQUJFKRXZMOKA-PAFIKIDNSA-N

InChI=1S/C21H20F5N3O4/c1-9-14(11-4-5-12(22)15(23)16(11)32-3)17(33-20(9,2)21(24,25)26)19(31)29-10-6-7-28-13(8-10)18(27)30/h4-9,14,17H,1-3H3,(H2,27,30)(H,28,29,31)/t9-,14-,17+,20+/m0/s1

4-[[(2R,3S,4S,5R)-3-(3,4-difluoro-2-methoxyphenyl)-4,5-dimethyl-5-(trifluoromethyl)oxolane-2-carbonyl]amino]pyridine-2-carboxamide

Suzetrigine; 2649467-58-1; JOURNAVX; VX-548; Suzetrigina; VX548; 4-[(2R,3S,4S,5R)-3-(3,4-Difluoro-2-methoxyphenyl)-4,5-dimethyl-5-(trifluoromethyl)oxolane-2-amido]pyridine-2-carboxamide; 4-[[(2R,3S,4S,5R)-3-(3,4-difluoro-2-methoxyphenyl)-4,5-dimethyl-5-(trifluoromethyl)oxolane-2-carbonyl]amino]pyridine-2-carboxamide;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: 125 mg/mL (264.05 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)