Experimental psoriasis treatment PTH (1-34) fails in clinical trial

Parathyroid Hormone (1-34) [PTH (1-34)], a topical cream that showed promise as a new treatment for psoriasis, failed to significantly reduce psoriasis symptoms in a Phase II clinical study, the company reported on July 31, 2008.

Manhattan Pharmaceuticals, the company sponsoring the study, compared two dosages of PTH (1-34) to placebo in more than 50 patients with mild-to-moderate plaque psoriasis. Patients using the drug did not experience an overall decrease in the severity of their psoriasis, nor did they see improvement in specific symptoms such as redness, scaling, plaque thickness, and itch. On the positive side, PTH (1-34) appeared to be safe (no serious side effects were reported) and well tolerated by patients. Manhattan is planning to further analyze the data from the trial before deciding how to proceed.

An earlier study of 15 patients, published in the British Journal of Dermatology in 2003, had indicated that PTH (1-34) was effective. Patients applying the drug experienced a 67% reduction in psoriasis severity as compared to an 18% reduction for patients using a placebo.

Drug research is expensive and difficult, as this experience shows. And there's no guarantee that a potential treatment that shows promise in initial tests will prove to be both safe and effective when facing the scrutiny of longer clinical trials. We're always disappointed to see a hoped-for psoriasis treatment not pan out, but glad that the psoriasis and psoriatic arthritis drug pipeline remains robust and promising.