Vertex Announces Positive Phase 2 Results For Suzetrigine In Lumbosacral Radiculopathy Pain Relief Portfolio

Vertex Pharmaceuticals has shared promising results from its Phase 2 trial of suzetrigine, an oral, highly selective NaV1.8 inhibitor. This aims to relieve pain in individuals with painful lumbosacral radiculopathy (LSR). The trial achieved its primary goal, demonstrating a statistically significant and clinically meaningful reduction in pain levels on the Numeric Pain Rating Scale (NPRS).

Efficacy Outcomes:

The study's main objective was to measure changes in participants' leg pain intensity over 12 weeks using the NPRS, which scores pain from 0 (no pain) to 10 (worst pain imaginable). By Week 12, patients in the suzetrigine group reported a significant average pain reduction of 2.02 points.

For comparison, the placebo group also showed an average pain reduction of 1.98 points. However, the trial was not designed to compare suzetrigine’s effects with the placebo directly. Post-hoc analyses revealed variability in placebo responses across study sites, a known challenge in pain research. 

At sites with lower placebo responses, suzetrigine showed a consistent reduction in pain, with greater differentiation from the placebo group. Vertex plans to incorporate these findings into the design of its future studies to better control placebo effects and highlight suzetrigine’s therapeutic benefits. 

Carmen Bozic, M.D., Executive Vice President, Global Medicines Development and Medical Affairs and Chief Medical Officer at Vertex, said in a statement, “Suzetrigine has again demonstrated its potential to fill an important unmet need in the treatment of pain. Today's LSR results are consistent with previous studies of this pain signal inhibitor in terms of showing a meaningful treatment effect across pain conditions and a favorable safety profile. We did not see separation between the suzetrigine and the placebo arms. Yet our post-hoc analyses suggest that this could be due to the high placebo response in this study. We remain committed to studying LSR and innovating our Phase 3 study design to control for the placebo effect as we advance suzetrigine into pivotal development for this condition.”

Safety Profile:

Suzetrigine was generally well tolerated. The rate of adverse events (AEs) was lower in the suzetrigine group (22.9%) compared to the placebo group (32.4%), with most AEs being mild to moderate. No serious adverse events related to suzetrigine were observed, and no participants discontinued treatment due to side effects. These results reinforce suzetrigine’s potential as a promising treatment for pain management, with Vertex planning to advance its development in future pivotal trials.

“The suzetrigine Phase 2 results clearly show reduced pain intensity from baseline in the active drug arm and the potential for suzetrigine to fill an unmet need in relieving LSR pain, a heterogeneous condition that is notoriously difficult to treat. Managing the placebo response in pain trials is a complex challenge. We look forward to innovating in clinical trial design, including for the pivotal study, with the aim of bringing a potentially safe and effective treatment to patients suffering from LSR," said Christine Sang, M.D., M.P.H., FASA, Director, Translational Pain Research, Brigham and Women's Hospital, Associate Professor of Anesthesia, Harvard Medical School, co-chair of Vertex’s Peripheral Neuropathic Pain steering committee, and lead principal investigator on the study.