The decision comes after the Independent Data Monitoring Committee (IDMC ) performed an unblinded, pre-planned interim analysis of the initial 50% subjects and recommended suspension of the trial for futility.
IDMC said that TNX-102 SL is not likely to show a statistically significant improvement on the primary endpoint of overall change in day-to-day diary pain severity scores from baseline compared to placebo.
The company is blinded to the interim analysis results and obtained the IDMC recommendation.
It intends to unblind the trial and report top-line data in the fourth quarter of this year after currently enrolled subjects complete the study.
As per preliminary blinded safety results, no new safety signals were reported and the discontinuation of enrolment is not linked to safety, the company noted.
Tonix Pharmaceuticals president and CEO Seth Lederman said: “We are surprised and disappointed that the interim analysis did not support continued enrolment in this Phase III RALLY study, especially considering the previous Phase III RELIEF study, which had a similar design and achieved statistical significance on the primary endpoint.
“After the currently enrolled participants complete the study, we will proceed with a full analysis of the unblinded data from the study to determine the next steps in this programme.”
TNX-102 SL is a sublingual tablet consisting of cyclobenzaprine hydrochloride. It has antagonist properties at the serotonin-2A, alpha-1 adrenergic, histamine-H1 and muscarinic-M1 receptors.
The double-blind, randomised, placebo-controlled, two-arm Phase III RALLY trial is assessing the efficacy and safety of the drug candidate in fibromyalgia. It recruited 514 subjects at about 40 sites in the US.
In March, Tonix Pharmaceuticals reported preliminary positive results after vaccinating primates with TNX-1800, a live modified horsepox virus vaccine designed to express the spike protein of the SARS-CoV-2 virus and to elicit a predominant T cell response.