Chelsea Therapeutics International, Ltd. announced that a new investigator-led phase II clinical study of droxidopa, an oral synthetic precursor of norepinephrine, has been initiated in chronic fatigue syndrome (CFS).

CFS is a complex and crippling disorder characterized by extreme fatigue that is not improved by rest. In addition to fatigue, patients with CFS experience symptoms, similar to that of fibromyalgia including, weakness, muscle pain, impaired memory and concentration. Droxidopa has been shown to improve symptoms of fatigue, weakness and concentration in neurogenic orthostatic hypotension associated with a variety of conditions including Parkinson's disease, multiple system atrophy and pure autonomic failure. Droxidopa is also being studied in an ongoing phase II trial in fibromyalgia where, during an interim analysis, an independent data monitoring committee saw meaningful efficacy in multiple treatment arms.

Dr Charles Lapp, a former board member of the American Association for CFS and medical advisor to the American Fibromyalgia Syndrome Association, is conducting this single-centre phase II study at the Hunter-Hopkins Center in Charlotte, North Carolina. The trial will evaluate up to 600 mg TID of droxidopa and assess the clinical efficacy using changes in Patient Global Impression of Improvement (PGI-I). In this open-label trial, approximately 20 patients will be titrated to optimal therapeutic benefit over a two-week period after which they will continue treatment for 12 weeks. The primary outcome measure will be changes in PGI-I scores from baseline to the end of the 12-week treatment period. Secondary measures include changes in the Multidimensional Fatigue Inventory (MFI), Clinical Global Impression of Severity (CGI-S), Hospital Anxiety and Depression Scale (HADS), blood pressure before and after a tilt table test.

"As we continue to work towards an approval for droxidopa for the treatment of neurogenic orthostatic hypotension, we are eager to expand the body of clinical research supporting potential indications that could be effectively treated with norepinephrine replacement therapy," said Dr Simon Pedder, president and CEO of Chelsea. "We welcome the opportunity to support Dr. Lapp's efforts to characterize the therapeutic role of norepinephrine in chronic fatigue syndrome and believe that a favourable outcome from this study, combined with data being generated by our ongoing phase II trials in fibromyalgia and adult attention deficit hyperactivity disorder, will further highlight the integral role of norepinephrine as a neurotransmitter central to the etiology of a host of disorders."

Droxidopa, the lead investigational agent in Chelsea Therapeutics' broad pipeline, is currently in phase III clinical trials for the treatment of symptomatic neurogenic orthostatic hypotension (NOH) in patients with primary autonomic failure – a group of diseases that includes Parkinson's disease, multiple systems atrophy (MSA) and pure autonomic failure (PAF). Droxidopa is a synthetic catecholamine that is directly converted to norepinephrine (NE) via decarboxylation, resulting in increased levels of NE in the nervous system, both centrally and peripherally. Droxidopa is also being studied for the treatment of fibromyalgia and adult attention deficit disorder in two ongoing phase II trials and completed a phase II in intradialytic hypotension (IDH) study with positive results.

Chelsea Therapeutics is a biopharmaceutical development company that acquires and develops innovative products for the treatment of a variety of human diseases.