VX-548 in the treatment of acute pain

Acute pain management requires balancing analgesia with adverse effects risk. The voltage-gated sodium channel NaV1.8 plays an important role in pain physiology, and its inhibition was shown to have analgesic effects. VX-548 is a new oral NaV1.8-specific inhibitor that received United States Food and Drug Administration Fast Track and Breakthrough Therapy designations. Its efficacy was demonstrated in two Phase II trials of patients who underwent abdominoplasty and bunionectomy. These showed that VX-548, when given as an oral loading dose of 100 mg followed by 50 mg 12-hly, significantly decreased pain scores compared with placebo. Similarly, two Phase III trials of patients who underwent abdominoplasty and bunionectomy comparing VX-548 with hydrocodone bitartrate-acetaminophen and placebo reported significantly reduced pain scores compared with placebo, but no improvement compared with hydrocodone bitartrate-acetaminophen. Evidence from Phase II and III trials suggest that VX-548 is well-tolerated, with headache, nausea, constipation and dizziness being the most common adverse effects. However, the safety of prolonged VX-548 administration is uncertain; a Phase II trial of patients with diabetic neuropathy who received high-dose VX-548 over 12 weeks reported decreased creatinine clearance. Data pertaining to VX-548 safety and efficacy within the context of multimodal analgesia and pregnancy are also needed.