Both the 200-mg and 350-mg dose groups showed numerically advantageous differences over placebo in secondary end points such as average daily pain score and 30% reduction in ADP.
Recently announced positive topline results from the phase 2 CONVEY study (NCT03339336) showed that treatment with 200-mg vixotrigine (previously known as BIIB074; Biogen) twice daily met its primary end point in reducing mean average daily pain (ADP) score for patients with small fiber neuropathy (SFN).1
Vixotrigine, a nonopioid investigational peripherally and centrally acting, orally administered, voltage- and use-dependent, voltage-gated sodium channel blocker, was evaluated on efficacy and safety in 265 patients with confirmed SFN that is idiopathic or associated with diabetes mellitus. At the end of the 12-week period, the 200-mg arm treatment group showed statistically significant reductions in mean ADP score compared with placebo (P = .0501). The company noted that the totality of data from the program will help inform potential doses for study in future phase 3 clinical trials.
"We are encouraged by the overall results of the CONVEY study, especially given the significant unmet medical need for additional agents to treat chronic painful neuropathy," Katherine Dawson, MD, senior vice president, and head, Therapeutics Development Unit, Biogen, said in a statement.1 "We are grateful to all the participants, investigators and study staff who contributed to this study and allowed us to evaluate vixotrigine as a nonopioid treatment option for people living with chronic neuropathic pain due to small fiber neuropathy.”
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In addition to reductions in ADP, the 200-mg dose group also demonstrated statistically significant improvement vs placebo on the mean worst daily pain score at week 12 (P = .0455). Although they did not meet statistical significance, this group also showed numeric advantages over placebo on secondary end points such as the proportion of patients with a 2-point or greater improvement in the average daily pain score and proportion of participants with at least 30% reduction in ADP at week 12.
Investigators also evaluated efficacy and safety of a 350-mg twice daily arm of vixotrigine and found that while it didn’t meet the primary end point, it met statistical significance the number of patients who reported they were “very much improved” or “much improved” on Patient Global Impression of Change (PGIC) at week 12 (P = .0580). Similar to the 200-mg treatment arm, the 350-mg dose group showed numeric improvements on secondary end points but did not reach statistical significance.
Vitoxtrigine was generally well-tolerated in both dose groups, with a safety profile that was consistent with what had been previously observed. Common adverse events (AEs), occurring in at least 2.5% of patients, were dizziness, headache, vertigo, and nausea. Most of these were mild or moderate in severity. In total, 5.3% of participants discontinued the open-label part of the study due to AEs.
There remains a significant unmet need for nonopioid treatments for patients with chronic neuropathic pain. Most recently, the FDA approved Nevro’s unique 10 kHz stimulation Senza System to treat patients with chronic pain associated with painful diabetic neuropathy (PDN), becoming the only spinal cord stimulation system approved by the FDA with a specific indication to treat PDN.2