Vertex’s stock hurt after non-opioid pain drug shows benefit similar to placebo

Vertex Pharmaceuticals’s non-opioid-based pain therapy has shown benefit in a Phase II trial in patients with painful lumbosacral radiculopathy (LSR) but is not too dissimilar to placebo.

The trial (NCT06176196), evaluating suzetrigine, an investigational, oral, highly selective NaV1.8 pain signal inhibitor met its primary endpoint with a statistically significant and clinically meaningful reduction in pain on the numeric pain rating scale (NPRS). The 11-point scale ranges from 0 (no pain) to 10 (worst pain imaginable).

The suzetrigine arm showed a statistically significant and clinically meaningful within-group reduction from baseline in pain with a mean change in NPRS of -2.02. The placebo arm was only 0.04 points worse, with a mean change in NPRS of -1.98. Vertex clarified that the study was not designed nor powered for statistical comparison between suzetrigine and placebo.

Investors were not convinced by Vertex’s bullish outlook on its data, with the company’s stock falling by 15.53% compared to market close yesterday (18 December).

Vertex also conducted post-hoc analyses to further evaluate the efficacy results which showed variability in the placebo response across study sites, a recognised issue in pain trials. The analysis suggest that trial design innovation may better control the placebo response and separate the treatment effect of suzetrigine from placebo in future studies, which Vertex will incorporate as it designs the pivotal programme.

Secondary and other endpoints were consistent with the study’s primary endpoint. Suzetrigine was also generally well tolerated in the study, with a 22.9% incidence of adverse events (AEs). There were no serious AEs or AEs leading to treatment discontinuation in patients treated with suzetrigine.

Dr. Carmen Bozic, executive vice president of global medicines development and medical affairs, said: “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 III study design to control for the placebo effect as we advance suzetrigine into pivotal development for this condition.”

Suzetrigine is a voltage-gated sodium channel inhibitor, specifically targeting NaV1.8. This channel is expressed in peripheral pain-sensing neurons, known as nociceptors, and plays a role in propagating pain signals.

Vertex completed a new drug application (NDA) submission to the US Food and Drug Administration (FDA) for the drug, with a Prescription Drug User Fee Act (PDUFA) target action date of 30 January 2025.