Studies show that patients with schizophrenia who are treated with Seroquel (quetiapine) experience an overall improvement across a broad range of symptoms associated with schizophrenia, including both positive and negative symptoms and cognitive functioning. These data add to the extensive set of clinical evidence demonstrating Seroquel's efficacy and tolerability in treating schizophrenia.
Results from the first study, the largest eight-week, double-blind, randomised clinical trial to date comparing Seroquel and risperidone (Risperdal) in the treatment of patients with schizophrenia, show Seroquel to be as effective as risperidone at improving the overall cognitive functioning of patients with schizophrenia. Cognitive deficiencies can be highly debilitating to patients with schizophrenia and can potentially compromise patient compliance, increasing the risk of relapse. At week 8, the overall improvement in cognitive functioning in patients treated with Seroquel was supported by significant improvements in specific aspects of cognitive functioning related to functional outcome: phonological fluency; learning and delayed recall; and social skills performance. The study included 673 acutely ill patients with schizophrenia who were randomised to treatment with Seroquel (mean daily dose was 525 mg/day) or risperidone (mean daily dose was 5.2 mg/day).
Commenting on the results, Dr. Philip Harvey from the Department of Psychiatry at the Mount Sinai School of Medicine in New York and lead investigator of the study, said, "For patients with schizophrenia, the inability to function in everyday life--think clearly, interact with other people, even write a letter--can have a devastating impact on their quality of life. Improving the cognitive functioning of patients is an essential element of any successful treatment strategy for schizophrenia and an important factor in allowing patients to reintegrate into society more easily. Clinicians should therefore be encouraged by these results, which confirm Seroquel's efficacy in this important symptom area."
The second study, conducted by Dr. Michael Riedel from Munich University Hospital, Germany, was a 12-week, double-blind, randomised parallel group comparison of Seroquel and risperidone in 44 schizophrenic patients who showed predominantly negative symptoms. The study demonstrated the similar efficacy of the two agents and also highlighted Seroquel's better tolerability. Specifically the results show the following:
- Both SEROQUEL and risperidone produced significant improvements in PANSS total and negative subscale scores compared with baseline
- Patients treated with risperidone had a significant increase from baseline in the incidence and severity of extrapyramidal (EPS) at weeks 3, 4, 5 and 7, whereas no significant increases in EPS were observed in Seroquel treated patients at any time
Results from the third study, presented again this week at CINP, support the proven efficacy of Seroquel in treating the positive symptoms of schizophrenia, and again highlight Seroquel's superior tolerability profile. Conducted by Professor Emilio Sacchetti, from the Brescia School of Medicine in Italy, the 16-week, multicenter, randomized parallel-group, rater-blinded, flexible dose study of 65 patients with schizophrenia, was the first direct comparison of Seroquel, olanzapine and risperidone in this setting. Specifically the results show the following:
- At week 8, PANSS total scores were improved by 34 percent with Seroquel, 30 percent with olanzapine and 29 percent with risperidone
- With respect to EPS, improvements in the SAS score was observed for Seroquel (-0.1 change from baseline by week 8) and olanzapine (-0.5 change from baseline by week 8), while a deterioration in SAS score was observed for risperidone (+2.4 change from baseline by week 8)
- At week 8, weight gain of less than 5 percent from baseline was observed in 37.5 percent (olanzapine), 28 percent (risperidone) and 16 percent (Seroquel) of patients
Seroquel is manufactured by AstraZeneca and has been licensed for use in schizophrenia since 1997. Seroquel combines broad-based efficacy in the treatment of positive, negative, cognitive and affective symptoms of schizophrenia, while offering excellent tolerability. The drug is associated with an incidence of EPS and prolactin elevation no different to placebo across the full dosage range, a favorable weight profile in long-term use and no clinically important effects on QT interval in most patients. To date, over 4 million people have been treated with Seroquel worldwide.