Xanomeline-trospium has shown promising results in clinical trials and has a unique mechanism of action.
Participants were randomly assigned to receive either KarXT or placebo orally twice a day for five weeks. Symptoms of schizophrenia were measured at screening, baseline, and weekly during the study with the Positive and Negative Syndrome Scale , a research instrument commonly used in studies of schizophrenia. The primary endpoint of the study was the change in total PANSS scores from baseline to week 5. Positive and negative symptoms were also followed using PANSS subscales.
Was KarXT beneficial? A meaningful response was defined as a 30 percent or greater reduction in total PANSS score by week 5. Using this definition, 55 percent of persons on KarXT responded versus 28 percent on placebo. This difference was both statistically significant and clinically meaningful. Importantly, both positive and negative symptoms improved. The difference between KarXT and placebo was evident by three weeks and further increased at five weeks.
Side effects were primarily gastrointestinal and occurred in both the KarXT and placebo groups, although they were higher in the KarXT group. The rates of serious or severe adverse events were low and occurred in both treatment groups to about the same degree. The effects of KarXT on cognitive symptoms were not reported in this study. However, earlier results suggested that KarXT may also improve cognitive symptoms.This is the first phase-3 study of KarXT. A second study is ongoing. Furthermore, longer studies examining results beyond five weeks are in progress. Should these additional studies replicate the findings of the Kaul et al.