Neurology · Medical Literature
Phase 2b Trial of a NaV1.8 Inhibitor for Acute Pain
Abstract
New England Journal of Medicine, Volume 395, Issue 5, Page 454-464, July 30, 2026.
Clinical relevance
In adults with moderate-to-severe acute postoperative pain following abdominoplasty, does the oral selective NaV1.8 inhibitor LTG-001 (at low or high doses) provide superior analgesia compared with placebo, and how does it compare with the opioid analgesic hydrocodone bitartrate–acetaminophen over 48 hours? __SNAPSHOT__ {"studyDesign":"Phase 2b, double-blind, randomized, placebo- and active comparator-controlled, four-arm dose-ranging trial (NCT07102459)","setting":"Multi-site; United States (specific institution types not reported in abstract)","sampleSize":"n = 343 (randomized 1:1:1:1 across four arms: high-dose LTG-001, low-dose LTG-001, hydrocodone bitartrate–acetaminophen, placebo; approximately 86 per arm [calculated])","population":"Adults with moderate-to-severe pain (as defined by the Verbal Categorical Rating Scale) after elective abdominoplasty; patients with chronic pain conditions and prior opioid use were excluded","intervention":"LTG-001 (oral, selective NaV1.8 inhibitor): high-dose arm — 450 mg loading dose followed by 300 mg every 12 hours; low-dose arm — 300 mg loading dose followed by 150 mg every 12 hours; all doses administered orally over 48 hours","comparator":"Active comparator: hydrocodone bitartrate 5 mg / acetaminophen 325 mg orally every 6 hours for 48 hours; Placebo arm: matching oral placebo every 6 hours for 48 hours","primaryOutcome":"Time-weighted sum of the pain-intensity difference over 48 hours (SPID48), derived from the Numeric Pain Rating Scale (NPRS; 0–10; higher SPID48 values indicate greater cumulative pain reduction)","followUp":"48 hours (treatment period); longer-term safety follow-up duration not reported in abstract","fundingSource":"Industry (Latigo Biotherapeutics, Thousand Oaks, CA)"}
Key findings
Both doses of LTG-001 demonstrated statistically significant superiority over placebo on the primary endpoint (SPID48). The high-dose regimen (450 mg / 300 mg q12h) achieved a least-squares mean SPID48 of 62.1 (difference vs. placebo: +62.08; P<0.001). The low-dose regimen (300 mg / 150 mg q12h) achieved a least-squares mean SPID48 difference vs. placebo of +37.82 (P=0.003), a result numerically comparable to the active comparator arm (hydrocodone bitartrate–acetaminophen SPID48 difference vs. placebo: +40.86; P-value for comparator vs. placebo not reported in abstract). The high-dose arm demonstrated approximately 50% greater analgesic effect than the opioid comparator, though formal statistical superiority of LTG-001 over the active comparator was not reported in the abstract. Median time to meaningful pain relief was approximately 52 minutes for high-dose LTG-001 versus 83 minutes for the opioid comparator (formal statistical comparison not reported in abstract). A clinically important opioid-sparing signal was observed: 52.3% of high-dose LTG-001 patients remained opioid-free throughout 48 hours versus 22.1% in the placebo arm (P<0.001), with significantly lower total opioid use in the high-dose group (11.00 morphine milligram equivalents [MME] vs. 18.35 MME; P=0.01). This opioid-sparing effect was not statistically significant in the low-dose group. NNT for opioid-free status (high-dose vs. placebo) = 1 / (0.523 − 0.221) = approximately 3.3 (calculated). A clear dose-response relationship was observed for both efficacy and opioid-sparing outcomes. Safety events of note at the high dose: pyrexia occurred in 7% vs. 2% (placebo) and presyncope in 6% vs. 1% (placebo); overall adverse event rates were reported as below those in the placebo arm. Confidence intervals for all primary and secondary endpoints were not reported in the abstract.
Practice implications
IMPORTANT LIMITATION: Only the abstract is available for this summary; the full manuscript data (including confidence intervals, subgroup analyses, safety tables, and pharmacokinetic data) have not been independently reviewed and may contain information that materially affects interpretation. This phase 2b trial establishes that LTG-001, a selective peripheral NaV1.8 inhibitor, produces statistically significant and apparently clinically meaningful analgesia over placebo in a validated postoperative pain model, with a dose-response relationship and a robust opioid-sparing signal at the high dose. The high-dose regimen appeared to numerically outperform the opioid comparator (hydrocodone/acetaminophen), though the trial was not formally powered to demonstrate superiority to the active comparator. What the study did NOT establish: long-term efficacy or safety beyond 48 hours; efficacy across diverse acute pain settings beyond the abdominoplasty model; applicability to patients with chronic pain, prior opioid use, or other comorbidities who were excluded; whether the presyncope signal is dose-limiting or mechanistically linked to NaV1.8 blockade; and effectiveness in the context of standard multimodal analgesia. The abdominoplasty population was predominantly female, raising uncertainty about generalizability to other surgical populations or sex-based differences in treatment effect. The SPID48 is an FDA-endorsed surrogate endpoint for postoperative pain, but its relationship to functional recovery, return to activities, or longer-term patient-reported outcomes has not been reported. Given that this is a phase 2b trial funded entirely by the sponsor and that a phase 3 program in bunionectomy is planned, these results are promising but require confirmatory phase 3 data before prescribing practice should change. The presyncope signal warrants close monitoring in phase 3. __LIMITATIONS__ Phase 2b design: underpowered to definitively establish superiority over the active opioid comparator; phase 3 confirmation required before regulatory submission or practice adoption.,Single surgical pain model (abdominoplasty): results may not generalize to other acute pain etiologies (non-surgical pain, orthopedic surgery, emergency settings).,Population homogeneity: predominantly female (reflecting the abdominoplasty demographic); the authors note that further research is needed to evaluate potential sex-based differential treatment effects.,Exclusion of patients with chronic pain conditions and prior opioid use limits applicability to a significant real-world subset of acute pain patients.,Short follow-up (48 hours): no data on analgesic durability, rebound pain, or safety signals beyond the treatment window.,Monotherapy assessment only: LTG-001 was evaluated as standalone therapy; the magnitude of benefit when incorporated into standard multimodal analgesia regimens is unknown.,Sole industry funding (Latigo Biotherapeutics) by a sponsor with direct financial interest in results; the lead author is the company's Chief Medical Officer.,Confidence intervals for primary and secondary endpoints were not reported in the abstract, precluding full assessment of precision.,The SPID48 is a surrogate endpoint; its correlation with functional recovery, patient satisfaction, or opioid use disorder prevention has not been established in this trial.,The clinical significance of the presyncope signal (6% vs. 1% placebo) requires further characterization in a larger, longer safety database.,SPID48 missing data were imputed using last observation carried forward, which may overestimate or underestimate benefit depending on dropout patterns. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ LTG-001, an investigational oral selective NaV1.8 inhibitor, met its primary efficacy endpoint in a 343-patient phase 2b trial, demonstrating statistically significant pain reduction versus placebo and a clinically notable opioid-sparing effect in the high-dose arm, with apparent numerical superiority over low-dose hydrocodone/acetaminophen. These results are promising and mechanistically compelling but are phase 2b only, restricted to a single 48-hour surgical model, funded exclusively by the sponsor, and require confirmatory phase 3 data — particularly across additional surgical models and in patients with comorbidities — before LTG-001 can be considered for clinical adoption.