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Phase 3 Trial of Corlux Misses Primary Endpoint
Patients whose plasma levels rose above a predetermined threshold statistically separated from both those whose plasma levels were below the threshold and those patients who received placebo. This confirmed a similar finding in Study 07, another Phase 3 trial testing CORLUX for PMD completed in 2006.
"While we are disappointed that the trial did not meet the primary endpoint, we are particularly encouraged to have met the important predefined threshold concentration endpoint with statistical significance," said Joseph K. Belanoff, M.D., Corcept's Chief Executive Officer. "This study confirms our previous observation that at higher plasma levels the drug candidate is able to demonstrate desired clinical effects. In particular, those patients in Study 06 who achieved a predetermined level of 1661 nanograms of CORLUX per milliliter of plasma separated from the placebo group with statistical significance."
Commenting on these results, Ned H. Kalin, M.D., Hedberg Professor and Chair of the Department of Psychiatry at the University of Wisconsin, said, "The correlation between plasma levels of drug and response rates found in this trial is very exciting. The results of this study show that when psychotically depressed patients achieve a threshold concentration of CORLUX in their system, a rapid and sustained clinical response is likely. This is a strong demonstration of a drug effect in an illness that is potentially devastating and difficult to treat." Dr. Kalin is a member of Corcept's Scientific Advisory Board.
Next Phase 3 Clinical Trial Being Planned
Robert L. Roe, M.D., Corcept's President, said, "We believe that the confirmation of a drug concentration threshold for efficacy as well as other observations from Study 06 and the company's two recently completed Phase 3 clinical trials will serve as a strong basis for the company's next Phase 3 study. In the upcoming trial, which is planned to commence later in 2007, we expect to use a dose level of 1200 mg once per day for seven days because, in Study 06, 80% of the patients achieved a drug plasma level sufficient for a strong clinical response at that dose. In our initial review of a summary of the safety data, we have seen no difference between any of the dose levels used in Study 06. We believe that this change in dose as well as other modifications to the protocol should allow us to definitively demonstrate the efficacy of CORLUX in the treatment of the psychotic features of PMD."
About Study 06
Study 06 was a randomized, double-blind, placebo-controlled study in which 443 patients were enrolled at 45 sites in the United States and Europe. The primary endpoint, a responder analysis, was the proportion of patients with at least a 50 percent improvement in the Brief Psychiatric Rating Scale Positive Symptom Subscale (BPRS PSS) at both Day 7 and Day 56. Specifically, the BPRS is an 18-item rating instrument used to assess psychopathology, and the PSS is a subset of four items in the BPRS that specifically measure psychosis. Patients were evenly distributed among three active dose groups (300 mg, 600 mg and 1200 mg) or a placebo group, with patients receiving once daily dosing for a period of seven days. All patients in the study were off any antidepressant and antipsychotic medication for at least one week before the seven day treatment period and received concomitant antidepressant therapy starting on Day 1 through Day 56. As was the case with the company's two previously completed Phase 3 studies evaluating CORLUX for PMD, treatment with antipsychotic medications or electroconvulsive therapy was not allowed at any time during this study. In Corcept's previous Phase 3 studies, as in Study 06, the response rate in patients who received CORLUX exceeded the response rate in patients who received placebo but not with statistical significance.
Source: Corcept Therapeutics