Manhattan Pharmaceuticals, Inc (NEW YORK, NY), a pharmaceutical company that acquires and develops drug candidates primarily for the treatment of dermatologic and immunologic disorders, announced that the first patient has received the initial dose of topical PTH (1-34) in a US multicenter, randomized, double-blind, vehicle-controlled, parallel group, phase IIa psoriasis study involving approximately 54 subjects randomized to receive one of two strengths of a reformulated topical PTH (1-34), or vehicle, for an 8-week treatment period. Originally planned for late 2005, the psoriasis study was postponed due to "issues identified with the current formulation and the difficulty of conducting a psoriasis study in the summer." The company has now finalized a proprietary, improved topical formulation for PTH (1-34).

A previously completed double-blind, placebo self-controlled phase I/II study, conducted under an investigator-IND at Boston University Medical Center, enrolled 15 adult patients with chronic plaque psoriasis who had failed to respond to at least one standard treatment. That study showed topical PTH (1-34) demonstrated a 67% improvement in the global severity score for the lesion treated with PTH (1-34) compared with the placebo-treated lesion, which showed only a 17.8% improvement. Patients topically applied 0.1 g of either Novasome A® (IGI, Inc) cream or Novasome A cream that contained 20 μg of PTH (1-34) twice a day for 2 months. Approximately 60% of the patients experienced a complete clearing of their lesions, with 85% experiencing at least partial clearing. Additionally, none of the patients experienced hypercalcemia or hypercalciuria or developed any side effect to the medication.

Human skin produces PTHrp (parathyroid hormone related peptide), a potent peptide inhibitor of epidermal cell growth. PTHrp is significantly reduced in the skin of psoriasis patients, leading to skin cell hyperproliferation, poor differentiation of skin cells, and ultimately, the accumulation of plaques. PTH (1-34), an agonist that mimics PTHrp, appears to help restore the normal development, migration and turnover of skin cells, reducing cell accumulation and the formation of plaques. Manhattan Pharmaceuticals has the rights to issued and pending patents for topical uses of PTH (1-34).