SEP 22, 2022 8:15 PM PDT

A new drug to treat the positive and negative symptoms of schizophrenia

WRITTEN BY: J. Bryce Ortiz

Schizophrenia is a severe psychiatric disorder that can affect an individual’s ability to properly interpret reality. This disorder is characterized by “positive” and “negative” symptoms. These characterizations do not refer to whether the symptom is good or bad, but rather whether the symptom is additive or subtractive to what is considered normal behavior. For example, positive symptoms of schizophrenia include hallucinations, delusions, or repetitive movements that are difficult to control. On the other hand, negative symptoms include difficulty talking, the inability to show emotion, and withdrawing from social relationships. 

For individuals diagnosed with schizophrenia, most current treatments have been shown to be effective at controlling positive symptoms of schizophrenia but generally fail to also treat the negative symptoms of the disorder. Now, a biotech company, Karuna Therapeutics, has announced positive results from their clinical trials on a new drug that aims to treat both positive and negative symptoms of the disorder. 

The most recent clinical trial studied the effects of the company’s drug, KarXT, on 252 adults living with schizophrenia. The participants were randomly assigned to receive KarXT or a placebo twice daily for 5 weeks. At the end of the 5-week period, the participants were assessed on a behavioral scale called the Positive and Negative Syndrome Scale, or PANSS for short. PANSS helps to measure the severity of positive and negative symptoms associated with schizophrenia. In the clinical trial, the patients who took KarXT showed a 21.2 point reduction on PANSS compared to an 11.6 point reduction in the patients who received placebo. In other words, KarXT helped patients with schizophrenia experience fewer debilitating symptoms. 


Karuna therapeutics CEO, Dr. Steve Paul, said, “These results represent our second positive registrational trial. We look forward to continuing to gather long-term safety data to support our submission of a New Drug Application with the U.S. Food and Drug Administration for KarXT as a treatment for schizophrenia, which we expect to occur in mid-2023.”

KarXT differs from other current pharmaceutical treatments for schizophrenia as it acts on muscarinicreceptors in the brain, while most schizophrenia treatments act on the dopamine system. While muscarinic receptor medications have been around for a few decades, their use in treating psychiatric disorders is limited due to their abundance of negative side effects. However, based on data from Karuna, KarXT has limited side effects and appears to be safe for use. The company will continue to move forward testing their drug, but they believe that the drug will, “redefine what successful treatment looks like for 21 million people living with schizophrenia.”


Sources: Karuna TherapeuticsnatureProgress in Neuro-Psychopharmacology and Biological PsychiatryCurrent Opinion in PharmacologyThe Psychiatrist

About the Author
Doctorate (PhD)
Science and medical writer | Researcher | Interested in the intersection between translational science, drug development, and policy
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