Predix records positive data on anxiety drug
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BY OUR PHARMA CORRESPONDENT
17th August,2005: Predix Pharmaceuticals, a drug discovery and development company, has begun the first pivotal phase III trial of PRX-00023, the company’s novel 5-HT1A agonist, in patients with generalized anxiety disorder (GAD).
The primary objective of the study is to evaluate the efficacy of PRX-00023 in GAD as measured by the change from baseline in the Hamilton Rating Scale for Anxiety (HAM-A).
This is the first of three internally discovered and developed drug candidates, currently in clinical trials, to enter phase III, Predix Pharmaceuticals announced in a press release.
Predix is currently in discussions with the Food and Drug Administration (FDA) regarding a Special Protocol Assessment (SPA) for this trial. The FDA has accepted the proposed study design and primary endpoint while making recommendations regarding secondary endpoint selection which we have adopted. At the FDA’s request, Predix is developing a detailed statistical analysis plan for this study to complete the SPA.
This phase III study follows the recent completion of a phase II study of PRX-00023 in patients with GAD. The phase II study was an open-label, multi-center outpatient trial in 20 patients with the diagnosis of moderate-to-severe GAD at study entry (HAM-A score of 20 or higher). The primary objective was to assess the safety and tolerability of PRX-00023 during short-term treatment of patients with GAD. Following a one-week, single-blinded placebo run-in period, PRX-00023 was administered to patients in doses of 40 mg once daily orally for four days, followed by 80 mg once daily orally for 10 days and then 120 mg once daily orally for 14 days. The most frequently reported adverse event was flu-like symptoms, occurring in three patients.
There were no serious adverse events or drug-related adverse events leading to discontinuation in the Phase II study. The only patient discontinuation was due to an adverse event that was not deemed drug-related. Although this trial was not designed to demonstrate statistical significance, preliminary results from the secondary efficacy objectives, available for 19 of the 20 patients, were encouraging. PRX-00023, given for four weeks, significantly lowered measures of anxiety from baseline in this trial, including the HAM-A total score, HAM-A psychic subscale score, CGI-Improvement score, and Hospital Anxiety and Depression scale. For example, analysis of HAM-A scores showed that 13 of 19 patients (68%) were "responders" with a reduction in their HAM-A score from baseline of at least 40%. Further, six of 19 patients (32%) experienced a "remission" of anxiety (i.e., a return to normal function), with a reduction in HAM-A score to seven or less during treatment with PRX-00023. These results are preliminary and are based on a small number of patients and are not necessarily predictive of results in later-stage clinical trials with larger and more diverse patient populations, the release said.
PRX-00023 is Predix’s lead drug candidate and represents a novel, highly selective , non-azapirone class of 5-HT1A agonists discovered using PREDICTTM, the company’s proprietary GPCR modeling, screening and lead optimization technology. Buspirone is currently the only 5-HT1A agonist approved in the United States for GAD, but must be taken three times a day, requires approximately three weeks of dose adjustment to reach therapeutic levels, and may cause lightheadedness and nausea. Several other 5-HT1A agonists have shown efficacy in phase II and III clinical trials in depression. However, most of these drugs belong to a chemical class of drugs called azapirones and their development has been hindered by poor tolerability at therapeutic doses, rapid metabolism, resulting in a short half-life and, therefore, requiring multiple daily dosing, and the requirement of slow dose escalation to effective doses because of nausea and lightheadedness, which are thought to be caused by their binding to off-target G-Protein Coupled Receptors (GPCRs).
In contrast, PRX-00023 is designed to have minimal affinity for the GPCRs associated with the side effects of 5-HT1A agonists that are in the azapirone chemical class, and to have a more convenient dosing profile than azapirones, the release added.
Predix Pharmaceuticals Holdings, Inc. is focused on the discovery and development of novel, highly selective, small-molecule drugs that target GPCRs and ion channels. Using its proprietary drug discovery technology and approach, Predix has advanced three drug candidates into clinical trials and has six additional programs in preclinical development and discovery. Predix’s lead clinical-stage drug candidate, PRX-00023, completed a phase II clinical trial in patients with GAD in July 2005 and entered the first of at least two pivotal phase III clinical trials for this indication in August 2005. Its two other clinical-stage drug candidates, PRX-03140 for the treatment of Alzheimer’s disease and PRX-08066 for the treatment of Pulmonary Arterial Hypertension are in phase I clinical trials.
BY OUR PHARMA CORRESPONDENT
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