Assessing Participant Experience with KarXT Treatment Using In-Trial Qualitative Interviews: Perceived Effect on Symptoms During a Long-Term Phase 3 Trial in Schizophrenia
KarXT is a novel investigational muscarinic M1/M4 receptor agonist that, unlike currently available antipsychotics, does not directly block dopamine D2 receptors. A new drug application for KarXT was recently accepted by the US Food and Drug Administration for the treatment of schizophrenia in adults. Since KarXT has a new mechanism of action, it is important to gather additional data on participants’ experience of taking KarXT, including symptom changes.
A qualitative interview-based sub-study was conducted with a subgroup of participants in a parent 52-week safety and efficacy study of KarXT monotherapy (NCT04820309). QualityMetric, an external research group with expertise in qualitative methods, conducted semi-structured interviews with each participant after ~6- and ~26-weeks of treatment to elicit their views about taking KarXT, including effects on symptoms. Coding and analysis of deidentified interview transcripts were conducted independently by QualityMetric.
70 participants completed an initial interview with 47 completing a follow-up interview. The majority of participants reported experiencing burdensome positive, negative, and cognitive symptoms at study entry. Most participants reported symptomatic improvements after approximately 6 weeks of treatment with KarXT (>50%) with a larger proportion reporting improvement by 26 weeks (>80%). Less than 5% reported worsening of symptoms.
Most participants reported broad initial and longer-term symptomatic improvements with KarXT. In their narratives, participants often described the symptomatic improvements as being personally significant and linked to functional benefits in their daily lives. These data add an important patient-centered perspective on a novel investigational muscarinic treatment.
